Ohio Department of Transportation Central Office • 1980 West Broad Street • Columbus, OH 43223 Ted Strickland, Governor • Jolene M. Molitoris, Director An Equal Opportunity Employer Date: April 16, 2010 To: All Current Holders of the Location and Design Manual, Volume 2 Re: Location and Design Manual, Volume Two Revisions Transmitted herewith are revisions to the Location and Design Manual, Volume 2. All revisions are indicated by a solid vertical bar to the left or right of the revised text. The following significant revisions have been made: • Section 1002.3 Design life clarified for Type B and C conduit. • Section 1008.1 Cambered flow line and foundation report modified. • Section 1008.2 Cambered flow line modified. • Section 1008.4 Foundation Report modified. • Section 1008.6 Skew language, design specifications and foundation report modified. • Section 1008.7 Skew language clarified and foundation report modified. • Section 1008.8 New section for Precast Reinforced Concrete Round Sections. • Section 1008.9 Renumbered section, modified D 50rock definition. • Sections 1008.10-1008.11 Renumbered. • Section 1009.2.1 Added maximum width for underdrain. • Section 1102.3.2 Corrected maximum slope for tied concrete block mat, added clarification for concrete channels. • Section 1103.2 Clarification on spread requirements. • Table 1104-1 Added Outside Diameter • Section 1104.2.3 New Section for Rock Excavation for Storm Sewer. • Section 1106.2.2 Modify plan requirements for full height headwalls. • Appendix B Modify Plan Notes D103 and D118. Delete Plan Note D120. The online revisions of the Location and Design Manual, Volume 2 can be found at http://www.dot.state.oh.us/Divisions/HighwayOps/Structures/Hydraulic/LandD/Pages/ TableofContents.aspx in PDF format. Technical questions or recommended changes should be directed to David Riley (614) 466-2599, John Stains (614) 728-1998 or Rebecca Humphreys (614) 387-1125. Respectfully, David Riley, P.E. Hydraulic Section Head DR:jps
Transcript
Ohio Department of Transportation Central Office • 1980 West Broad Street • Columbus, OH 43223
Ted Strickland, Governor • Jolene M. Molitoris, Director
An Equal Opportunity Employer
Date: April 16, 2010 To: All Current Holders of the Location and Design Manual, Volume 2 Re: Location and Design Manual, Volume Two Revisions Transmitted herewith are revisions to the Location and Design Manual, Volume 2. All revisions are indicated by a solid vertical bar to the left or right of the revised text. The following significant revisions have been made:
• Section 1002.3 Design life clarified for Type B and C conduit. • Section 1008.1 Cambered flow line and foundation report modified. • Section 1008.2 Cambered flow line modified. • Section 1008.4 Foundation Report modified. • Section 1008.6 Skew language, design specifications and foundation report
modified. • Section 1008.7 Skew language clarified and foundation report modified. • Section 1008.8 New section for Precast Reinforced Concrete Round Sections. • Section 1008.9 Renumbered section, modified D50rock definition. • Sections 1008.10-1008.11 Renumbered. • Section 1009.2.1 Added maximum width for underdrain. • Section 1102.3.2 Corrected maximum slope for tied concrete block mat,
added clarification for concrete channels. • Section 1103.2 Clarification on spread requirements. • Table 1104-1 Added Outside Diameter • Section 1104.2.3 New Section for Rock Excavation for Storm Sewer. • Section 1106.2.2 Modify plan requirements for full height headwalls. • Appendix B Modify Plan Notes D103 and D118. Delete Plan Note D120.
The online revisions of the Location and Design Manual, Volume 2 can be found at http://www.dot.state.oh.us/Divisions/HighwayOps/Structures/Hydraulic/LandD/Pages/TableofContents.aspx in PDF format. Technical questions or recommended changes should be directed to David Riley (614) 466-2599, John Stains (614) 728-1998 or Rebecca Humphreys (614) 387-1125. Respectfully,
David Riley, P.E. Hydraulic Section Head DR:jps
Notice To ensure proper receipt of future revisions to the manual, please visit the online Design Reference Resource at: http://www.dot.state.oh.us/drrc/. This manual is produced by the Hydraulic Section, Office of Structural Engineering. Technical questions should be directed to: David Riley, P.E. Hydraulic Section Head ([email protected]) (614) 466-2599 Recommended changes or suggestions should be sent to: Ohio Department of Transportation Office of Structural Engineering Attn: David Riley, P.E. Hydraulic Section Head 1980 West Broad Street Columbus, Ohio 43223
Table of Contents (Revised April 2010)
Preface ...............................................................................................................................................i Ohio Counties ................................................................................................................................... iii Concordance ..................................................................................................................................... iv Glossary of Terms ..............................................................................................................................v Design Reference Documents ............................................................................................................ ix Drainage Design Policies 1000 1001 Hydraulic Design Policy ......................................................................................................10-1
1003 Hydrology ............................................................................................................................10-4 1003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams ..........................10-4
1004 Flood Clearance ..................................................................................................................10-5 1004.1 General..................................................................................................................10-5 1004.2 Design Year Frequency ..........................................................................................10-5 1004.3 Plan Designation ....................................................................................................10-5
1005 Highway Encroachments on Flood Plains ...........................................................................10-5 1005.1 General..................................................................................................................10-5 1005.2 Type of Studies ......................................................................................................10-6
1112 Notice of Intent (NOI) ......................................................................................................... 11-23 1112.1 General................................................................................................................ 11-23 1112.2 Routine Maintenance Project................................................................................. 11-24 1112.3 Watershed Specific NOI Requirements .................................................................. 11-24
1113 Erosion Control at Bridge Ends......................................................................................... 11-25 1113.1 General................................................................................................................ 11-25 1113.2 Corner Cone ........................................................................................................ 11-25
1114 Temporary Sediment and Erosion Control ........................................................................ 11-25 1114.1 General................................................................................................................ 11-25 1114.2 Cost Estimate for Temporary Sediment and Erosion Control ................................... 11-25
1115 Post Construction Storm Water Structural Best Management Practices........................... 11-25 1115.1 General................................................................................................................ 11-25 1115.2 Project Thresholds for Post-Construction BMP ....................................................... 11-25 1115.3 Water Quality and Water Quantity Treatment.......................................................... 11-26 1115.4 Water Quality Volume ........................................................................................... 11-27 1115.5 Water Quality Flow ............................................................................................... 11-27 1115.6 Redevelopment and New Construction .................................................................. 11-27
APPENDIX A – Reproducible Forms APPENDIX B – Sample Plan Notes APPENDIX C – Drainage Design Aids
Appendix C has been removed from the printed manual. Drainage Aids can be found at http://www.dot.state.oh.us/se/hy/Drainage%20Design%20Aids/drainageaids.htm
Preface
April 2010 i
Purpose This Drainage Design Manual has been prepared as a guide for the hydraulic design of highway drainage facilities. Drainage has long been recognized as one of the essential parts of the highway, and the cost involved in the adequate removal of surface and subsurface water justifies a careful and scientific hydraulic analysis.
The time required to determine by hydraulic principles such basic information as size and shape of a conduit, the need for temporary and/or permanent open channel protection, and the proper spacing of catch basins or pavement inlets constitutes a relatively small percentage of the total time required to prepare a set of highway plans. The fact that drainage facilities for most highway projects will account for approximately 25% of the total cost of the project is further justification for a detailed hydraulic analysis.
Application Adhering to recommended design procedures and controls noted in this manual should result in drainage facilities that will preclude the following:
A. Damage of private property due to flooding.
B. Undue inconvenience to the motorist during moderate to heavy rainfall.
C. Undue disturbance to the environment.
Numerous charts have been prepared and are included in the Drainage Design Aids Section of this manual to assist the Drainage Design Engineer with the hydraulic analysis. Other design charts are available in Hydraulic Engineering Circulars and Hydraulic Design Series prepared by the Federal Highway Administration. Reference is made to those charts as required.
This manual is neither a textbook nor a substitute for engineering knowledge, experience, or judgment. It is intended to provide uniform procedures for implementing drainage design decisions and assure quality and continuity in drainage of highways in Ohio. Although the manual is considered a primary source of reference by personnel involved in drainage design in Ohio, it must be recognized that the practices suggested may be inappropriate for some projects because of fiscal limitations or other justifiable reasons.
Consideration must also be given to justifiable hydraulic design standards adopted by city, county, or other local governments when designing facilities under their jurisdiction.
Preparation The Drainage Design Manual has been developed by the Hydraulic Section, Office of Structural Engineering. Errors or omissions should be reported to the Office Administrator, Office of Structural Engineering, Ohio Department of Transportation, 1980 W. Broad Street, Columbus, Ohio 43223.
Format and Revisions Updating the manual is intended to be a continuous process and revisions will be issued periodically.
Although pages are individually numbered within each section, new pages may be added and identified with letter suffixes after the page numbers. For example, two new pages between 10-4 and 10-5 would be numbered 10-4a and 10-4b. Figures do not have page numbers, but are numbered to coincide with the section number in the text. For example, Figure 1102-2 is the second figure listed in Section 1102. Additional figures may be added by either going to the next highest number or using a letter suffix. It should also be noted that figures are located at the end of each main section and are printed on colored paper for easy reference.
Each page has the latest date shown on the lower left hand corner. Revisions will be issued periodically by the Office of Structural Engineering. The loose-leaf format of the manual makes updating a quick and simple task. Users are encouraged to keep their copies up-to-date.
April 2010 ii
Ohio Counties
April 2010 iii
County Code District Adams ADA 9 Allen ALL 1 Ashland ASD 3 Ashtabula ATB 4 Athens ATH 10 Auglaize AUG 7 Belmont BEL 11 Brown BRO 9 Butler BUT 8 Carroll CAR 11 Champaign CHP 7 Clark CLA 7 Clermont CLE 8 Clinton CLI 8 Columbiana COL 11 Coshocton COS 5 Crawford CRA 3 Cuyahoga CUY 12 Darke DAR 7 Defiance DEF 1 Delaware DEL 6 Erie ERI 3 Fairfield FAI 5 Fayette FAY 6 Franklin FRA 6 Fulton FUL 2 Gallia GAL 10 Geauga GEA 12 Greene GRE 8 Guernsey GUE 5 Hamilton HAM 8 Hancock HAN 1 Hardin HAR 1 Harrison HAS 11 Henry HEN 2 Highland HIG 9 Hocking HOC 10 Holmes HOL 11 Huron HUR 3 Jackson JAC 9 Jefferson JEF 11 Knox KNO 5 Lake LAK 12 Lawrence LAW 9
County Code District Licking LIC 5 Logan LOG 7 Lorain LOR 3 Lucas LUC 2 Madison MAD 6 Mahoning MAH 4 Marion MAR 6 Medina MED 3 Meigs MEG 10 Mercer MER 7 Miami MIA 7 Monroe MOE 10 Montgomery MOT 7 Morgan MRG 10 Morrow MRW 6 Muskingum MUS 5 Noble NOB 10 Ottawa OTT 2 Paulding PAU 1 Perry PER 5 Pickaway PIC 6 Pike PIK 9 Portage POR 4 Preble PRE 8 Putnam PUT 1 Richland RIC 3 Ross ROS 9 Sandusky SAN 2 Scioto SCI 9 Seneca SEN 2 Shelby SHE 7 Stark STA 4 Summit SUM 4 Trumbull TRU 4 Tuscarawas TUS 11 Union UNI 6 Van Wert VAN 1 Vinton VIN 10 Warren WAR 8 Washington WAS 10 Wayne WAY 3 Williams WIL 2 Wood WOO 2 Wyandot WYA 1
Conduits Flexible 10-1, 11-5, 11-7, 11-11, 11-20, 11-22 Rigid 10-1, 10-7, 10-13, 11-11 Type A 10-2 Type B 10-3, 11-11 Type C 10-3, 11-11 Type D 10-3, 11-19 Type E 10-3, 10-4 Type F 10-4, 11-11, 11-21
Corner Bearing Pressure 10-8 Corrugated Metal Pipe
Aggregate Drain - A trench filled with granular material extending laterally from the pavement base or subbase layer to an outlet on the roadway foreslope with the intent of draining surface and/or ground water away from the pavement base and/or subbase.
Anti-seep Collar – Device that prevents the flow of water through the surrounding soil around a conduit that is used as an outlet for an infiltration, retention, or detention basin.
Apron - Paving at a pipe inlet or outlet, or upstream of a catch basin, constructed along the channel bottom to prevent scour.
Backwater Analysis - The determination of water surface profiles measured at specific locations upstream from a constriction causing an increased flow depth upstream.
Bankfull Discharge – The flow or stage of a stream corresponding to the highest level of active deposition. It is the discharge that, on the average, fills a main channel to the point of overflowing. For simplicity, it is generally considered to be approximately the 2 year discharge.
Camber - A slight convex curve constructed into the bottom of a pipe to overcome anticipated settlement problems.
Cast-in-place Structure - A concrete drainage structure which is placed in forms and cured at its final location. Precast beams on cast-in-place foundations are considered cast-in-place structures.
Catch Basin - A structure for intercepting flow from a gutter or ditch and discharging the water through a conduit.
Coefficient of Runoff (C) - A value, varying with the ground and ground cover, which is used in the Rational formula to determine the amount of a rainfall which is directed to streams and not absorbed into the ground.
Conduit - A closed structure such as a pipe.
Corner Bearing Pressure - The pressure generated at the corners of pipe arch structures.
Culvert - A structure which is typically designed hydraulically to take advantage of submergence at the inlet to increase hydraulic capacity. A structure used to convey surface runoff through
embankments. A structure, as distinguished from a bridge, which is usually covered with embankment and is composed of structural material around the entire perimeter, although some are supported on spread footings with the stream bed serving as the bottom of the culvert.
Cutoff Wall - A wall that extends downward from the end of a structure to below the expected scour depth, or to a scour-resistant material.
Design Discharge (Q) - The peak rate of flow for which a drainage facility is designed. Usually given in cubic feet per second (cfs).
Design Service Life - The desired usable life of a pipe or structure. Certain drainage situations require a 50-year life, more stringent situations require a 75-year design life.
Design Storm - A given rainfall amount, areal distribution, and a time distribution, used to estimate runoff. The rainfall amount is either a given frequency (25-year, 50-year, etc.) or a specific large value.
Detention Basin – A structure that holds water for a short period of time before releasing it to the natural water course.
Diversion Dike - An embankment to control or to deflect water away from a soil bank.
Drainage Area - The area contributing discharge to a stream at a given point.
Drop-down Entrance (Drop inlet) - A type of inlet which conveys the water from a higher elevation to a lower elevation smoothly without a free fall at the inlet.
Elliptical Pipe - Pipe which is manufactured with a span greater than rise to be utilized in shallow cover situations.
Ephemeral Stream – A stream or reach of stream that does not flow for parts of the year. As used here, the term includes intermittent streams with flow less than perennial. It is located above the water table year-round. Ground water is not a source of water supply.
Feasible – Term used to define BMP practicability. BMP shall be: technically feasible, implemented within the procured highway right -of-way, safe for the traveling public and ODOT maintenance personnel, cost effective as
April 2010 vi
compared to the benefit, and will be legal at the State, Federal, and Local levels. FEMA – Federal Emergency Management Agency.
Flood Fringe – The portion of the floodplain outside of the floodway.
Flood Hazard Evaluation - The act of determining if flood levels within a watercourse for a 100-year flood, or other recurrence interval floods have a significantly increased detrimental impact on upstream property.
Flood Plain – Lowland and relatively flat areas adjoining inland and coastal waters including, at a minimum, that area subject to a one percent or greater chance of flooding in any given year. This area encompasses the floodway and the floodway fringe.
Flood Plain Culverts – Relief culverts that are placed in addition to a bankfull culvert at a higher elevation across the flood plain to allow multiple outlets for floodwaters.
Forebay – Depressed area that offers pretreatment of sediment laden storm water prior to a retention, detention, or infiltration basin. Flood Plain Study - A more extensive analysis of the effects of flood levels on upstream property than the Flood Hazard Evaluation. This analysis is to be used when upstream properties appear to have been subjected to a significantly increased detrimental effect from the flood flows.
Floodway – The portion of the floodplain which is effective in carrying flow, within which this carrying capacity must be preserved and where the flood hazard is generally highest.
Friction Slope - The slope of the energy grade line.
Granular Material - A term relating to the uniform size of grains or crystals in rock, larger than sand or pea gravel.
Grate - A type of screen made from sets of bars used to allow the interception of flow, and also to cover an area for pedestrian or vehicular traffic.
Headwall - The structural appurtenance placed at the open end of a pipe to control an adjacent highway embankment and protect the pipe end from undercutting.
Headwater - That depth of water impounded upstream of a culvert due to the influence of the culvert constriction, friction, and configuration.
Highest Known Water Elevation – The highest known flood water in record.
Hydraulic Grade Line - A line coinciding with the level of flowing water in an open channel. In a closed conduit operating under pressure, a line representing the distance water would rise in a pitot tube at any point along a pipe. The hydraulic grade line is equal to the pressure head (P/?) along the pipe.
Hydraulic Gradient - The slope of the hydraulic grade line for a storm sewer or culvert.
Idealized Channel Geometry - Physical, geometric, and hydraulic characteristics of a channel determined from empirical relationships.
Impervious Surface – Hardened pavement surface. Infiltration Rate – The rate at which water penetrates the surface of the soil at any given instant. The rate can be limited by the infiltration capacity of the soil or the rate at which water is applied.
Inlet - A structure for capturing concentrated surface flow. May be located along the roadway, in a gutter, in the highway median, or in the field.
Inlet Control - The situation where the culvert hydraulic performance is controlled by the entrance geometry only.
Intermittent Stream – A stream that is dry for part of the year, ordinarily more than 3 months.
Manhole - A structure by which one may access a closed drainage system.
MS4 Phase II Regulated Area – Area that has been designated by the Ohio EPA that requires a storm water management plan to discharge storm water.
Multiple Cell Culvert - A culvert with more than one barrel.
New Development Project – Projects that change the land use of a site from undeveloped to developed characteristics.
April 2010 vii
Normal Water Elevation – The water elevation in a stream which has not been affected by a recent heavy rain runoff. The water level which could be found in the stream most of the year. This elevation will be lower than the ordinary high water.
Ordinary High Water – The line on the shore established by the fluctuation of water and indicated by physical characteristics such as: a clear natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, or other appropriate means that consider the characteristics of the surrounding areas. This elevation is lower than the highest known water.
Outlet Control - The situation where the culvert hydraulic performance is determined by the controlling water surface elevation at the outlet, the slope, length and roughness of the culvert barrel, as well as the entrance geometry.
Overland Flow - Water which travels over a surface and reaches a stream.
Perennial Stream – A stream that flows continuously for all or most of the year. The water table is located above the stream bed for most of the year.
Permeability – The quality of the soil that enables water to move downward through the soil profile. It is measured in units of inches per hour.
pH - The reciprocal of the negative logarithm of the Hydrogen ion concentration. Neutral water has a pH value of 7. A measure of the acidity of a substance, if less than 7; alkalinity if greater than 7.
Pipe Arch - Pipe which is manufactured with a span greater than rise (semicircular crown, small-radius corners, and large radius invert) to be utilized in shallow cover situations.
Pipe Underdrain - A longitudinal subsurface drainage system composed of a perforated pipe at the bottom of a narrow trench filled with permeable material and lined with a geotextile in erodible soils, with the intent of draining surface and/or ground waters away from the pavement base and/or subbase.
Porosity – The volume of voids divided by the total volume and multiplied by 100.
Prefabricated Edge Drain - A longitudinal underdrain system utilizing a narrow trench and a vertically elongated, perforated water carrier with the intent of draining surface and/or ground water away from the pavement base and/or subbase.
Prefabricated Structure - Any drainage structure which is manufactured off site and transported to the location of intended use. It may be of various materials, including concrete, clay, metal, thermoplastics, etc. It may be of various shapes including circular, elliptical, rectangular, arched, etc.
Premium Joints - Watertight joints.
Pretreatment – Preliminary filtering of sediment laden storm water prior to secondary treatment through a structural best management practice. Rainfall Intensity (i) - The amount of rainfall occurring in a unit of time, normally given in inches per hour.
Reference Reach - A length of channel with stable geometric, physical, and hydraulic characteristics. A representation of the desired outcome of a restored channel.
Retention Basin – A structure that holds water on a permanent basis. Roughness Coefficient (n) - The measure of texture on the surface of channels and conduits. Usually represented by the “n-value” coefficient used in Manning’s open channel flow equation.
Runoff - That part of the precipitation which runs off the surface of a drainage area after all abstractions are accounted for.
Sanitary Sewer - A conduit or pipe system which carries household and/or industrial wastes. Sanitary sewers do not convey storm water.
Sediment Basin - A basin or tank in which stormwater containing settleable solids is retained, to remove by gravity or filtration a part of the suspended matter.
Sediment Dam - A dam that is designed to allow suspended sediment to settle out of flowing water in a controlled area.
Short-circuiting – The act of storm water bypassing the intended route.
April 2010 viii
Soil Bioengineering – The use of live and dead plant materials, in combination with natural and synthetic support materials, for slope stabilization, erosion reduction, and vegetative establishment.
Spring Line - The locus of the horizontal extremities of a transverse section of a conduit.
Step Backwater or Standard Step Method - An iterative use of the energy equation for determining the water surface profile of an open channel.
Storm Sewer - A conduit or pipe drainage system that conveys storm water, subsurface water, condensate, or similar discharge, but not household or industrial wastes.
Tailwater - The depth of flow in the stream directly downstream of a drainage facility, measured from the invert at the culvert outlet. Often calculated for the discharge flowing in the natural stream without the highway constriction. Term is usually used in culvert design and is the depth measured from the downstream flow line of the culvert to the water surface.
Time of Concentration (tc) - Time required for water to flow from the most distant point on a drainage area to the measurement or collection point.
TMDL (total maximum daily load) Regulated Stream – An Impaired water body as defined by the Ohio EPA that can still meet water quality standards if the daily maximum pollutant load is regulated. Two Stage Channel – A channel that contains a cross sectional area for low and high discharges. Water of The United States - Water bodies subject to Army Corps of Engineers jurisdiction through Section 404 of the Clean Water Act. They include all interstate waters such as lakes, rivers, streams (including intermittent streams) and wetlands. Ephemeral streams are included if they have a clearly defined channel.
Design Reference Documents
April 2010 ix
C Hydraulics of Bridge Waterways (FHWA Hydraulic Design Series No. 1)
C Highway Hydrology (FHWA Hydraulic Design
Series No. 2) C Design Charts for Open Channel Flow (FHWA
Hydraulic Design Series No. 3) C Hydraulic Design of Highway Culverts (FHWA
Hydraulic Design Series No. 5) C River Engineering For Highway Encroachments
(FHWA Hydraulic Series No. 6) C Design of Stable Channels with Flexible Linings
(Federal Highway Engineering Circular No. 15) C Evaluating Scour at Bridges (FHWA Hydraulic
Engineering Circular No. 18) C Urban Drainage Design Manual Second Edition
(FHWA Hydraulic Engineering Circular No. 22) C Techniques for Estimating Flood-Peak
Discharges of Rural Unregulated Streams in Ohio (USGS Water-Resources Investigations Report 89-4126)
C Estimation of Peak-Frequency Relations, Flood
Hydrographs, and Volume - Duration - Frequency Relations of Ungaged Small Urban Streams in Ohio (USGS Open-File Report 93-135)
C Estimation of Flood Volumes and Simulation of
Flood Hydrographs for Ungaged Small Rural Streams in Ohio (USGS Water Resources Investigations Report 93-4080)
C Culvert Durability Study (ODOT/L&D/82-1) C Internal Energy Dissipators for Culverts
(FHWA/OH-84/007) C Standard Construction Drawings (ODOT) C Construction and Material Specifications
Handbook (ODOT) C Rainwater and Land Development, Ohio’s
Standards for Stormwater Management Land Development and Urban Stream Protection (Second Edition, 1996).
C Stream Corridor Restoration: Principles,
Practices and Processes (United States Department of Agriculture), October 1998
Caltrans Storm Water Quality Handbooks, Project Planning and Design Guide, September 2002. (http://www.dot.ca.gov/hq/construc/stormwater/manuals.htm) Caltrans Storm Water Quality Handbooks, Municipal Handbook , March 1993. New York State Stormwater Management Design Manual, October 2001. http://www.dec.state.ny.us/website/dow/swmanual/swmanual.html Maryland Storm Water Design Manual, October 2000 (http://www.mde.state.md.us/Programs/WaterPrograms/SedimentandStormwater/stormwater_design/index. asp) FHWA Ultra Urban BMP webpage. (http://www.fhwa.dot.gov/environment/ultraurb/index.htm) USEPA National Pollutant Discharge webpage (http://cfpub.epa.gov/npdes/stormwater/menuofBMP/menu.cfm ) Urban Runoff Quality Management, WEF Manual of Practice No. 23, 1998, published jointly by the WEF and ASCE. Rainwater and Land Development Manual, Ohio Department of Natural Resources, Draft version not yet published. Storm Water Technology Fact Sheet - Bioretention, September 1999, EPA 832-F-99-0125, http://www.epa.gov/owmitnet/mtb/biortn.pdf. Ohio Environmental Protection Agency, Authorization for Storm Water Discharges Associated With Construction Activity Under The National Pollutant Discharge Elimination System, Permit OHC000002, April 21, 2003, http://www.epa.state.oh.us/dsw/permits/CGP_renewal_final.pdf. Storm water Pollutant Removal in Roadside
Vegetated Buffer Strips, Michael Barrett, Center for Research in Water Resources, University of Austin, TX., TRB 2004.
1002.1.1 Deviation by ODOT Districts .....................................................................10-1 1002.1.2 Deviation by Local ...................................................................................10-1
1002.2 General Requirements ............................................................................................10-1 1002.2.1 Pipe Materials..........................................................................................10-1 1002.2.2 Outlet Velocity Control..............................................................................10-1 1002.2.3 Special Shapes........................................................................................10-2 1002.2.4 Structure File Number ..............................................................................10-2
1002.3 Conduit Types ........................................................................................................10-2 1002.3.1 Type A Conduits ......................................................................................10-2 1002.3.2 Type B Conduits ......................................................................................10-3 1002.3.3 Type C Conduits ......................................................................................10-3 1002.3.4 Type D Conduits ......................................................................................10-3 1002.3.5 Type E Conduits ......................................................................................10-4 1002.3.6 Type F Conduits ......................................................................................10-4 1002.3.7 Liner Pipe................................................................................................10-4
1003 Hydrology ............................................................................................................................10-4 1003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams ..........................10-4
1003.1.1 General ...................................................................................................10-4 1003.1.2 Limitations ...............................................................................................10-5
1004 Flood Clearance ..................................................................................................................10-5 1004.1 General..................................................................................................................10-5 1004.2 Design Year Frequency ..........................................................................................10-5 1004.3 Plan Designation ....................................................................................................10-5
1005 Highway Encroachments on Flood Plains ...........................................................................10-5 1005.1 General..................................................................................................................10-5 1005.2 Type of Studies ......................................................................................................10-6
1008 Structural Design Criteria ....................................................................................................10-8 1008.1 Corrugated and Spiral Rib Steel and Aluminum Pipes, and Corrugated Steel and Aluminum Pipe Arches .......................................................................................................10-8
1008.1.1 Material Durability ....................................................................................10-8 1008.1.2 Designation and Thickness.......................................................................10-8 1008.1.3 Cambered Flow Line ................................................................................10-8 1008.1.4 Height of Cover........................................................................................10-8 1008.1.5 Foundation Reports .................................................................................10-8 1008.1.6 Corner Bearing Pressures ........................................................................10-8
1008.2 Rigid Pipe ..............................................................................................................10-8 1008.2.1 General ...................................................................................................10-8
1008.2.2 Height of Cover........................................................................................10-9 1008.2.3 Structural Design Criteria .........................................................................10-9
1008.3 Thermoplastic Pipe .................................................................................................10-9 1008.3.1 Height of Cover........................................................................................10-9
1008.4 Corrugated Steel and Aluminum Box Culverts and Corrugated Steel Long Span Culverts..........................................................................................................................................10-9
1008.4.1 Designation and Thickness.......................................................................10-9 1008.4.2 Height of Cover........................................................................................10-9 1008.4.3 Foundation Reports .................................................................................10-9
The Hydraulic Section, Office of Structural Engineering is responsible for the hydraulic and structural design standards of all prefabricated and cast-in-place structures including concrete pipe, vitrified clay pipe, corrugated metal pipe, thermoplastic pipe, box culverts, three-sided flat -topped and arch structures, etc., regardless of structure size or contributing drainage area. This includes the preparation of permissible surcharge tables for flexible and rigid pipe and coordination with Specification Committee for the material portions of the Construction and Material Specifications. The Hydraulic Section is also responsible for the structural and hydraulic adequacies of all headwalls or endwalls used in conjunction with structures. Further responsibility includes all surface drainage systems including roadway ditches and channels. The Hydraulic Section, Office of Structural Engineering, is also responsible for the determination of the type of drainage structure (i.e., prefabricated vs. cast-in-place) required to replace an existing bridge (span length greater than 10 feet). 1001.2 Natural Streams
Channel designs and channel relocations of all natural streams passing through a proposed highway facility will be the responsibility of whichever Departmental Office has the responsibility for the highway structure. All other channel designs and channel relocations of natural streams shall be the responsibility of the Hydraulic Section.
1002 Pipe Policy
1002.1 Introduction
The policies herein shall govern in the determination of the size and type of pipe specified or permitted for the various items of highway drainage financed totally or in part with state or federal funds. Any deviations from this Pipe Policy concerning type of pipe or pipe placement must be based on sound engineering judgment and/or life cycle cost analysis. Deviations involving the specification of only one type of pipe material where special
conditions prevail must include sound engineering judgment such as:
• Excessive cover for a rigid pipe • Where a larger corrugated pipe would
require a higher pavement grade to satisfy minimum cover requirements or require more cells than a rigid alternate
• Where a metal pipe arch would be required as an alternate to a round rigid pipe.
The use of a single material type is subject to the approval of the Hydraulic Section, Office of Structural Engineering. 1002.1.1 Deviation by ODOT Districts A written request for deviation from this Pipe Policy by ODOT Districts, with the necessary documentation, shall be submitted to the Administrator of the Office of Structural Engineering. The request shall be made with the Drainage Criteria submission. 1002.1.2 Deviation by Local Proposed deviations from this Pipe Policy by local political subdivisions or agencies will be considered for all portions of the project that the political subdivision or agency will be responsible for maintaining at its own expense. The local subdivision or agency shall submit a written request for deviation from this Pipe Policy, with the necessary documentation, to the local ODOT District, who will in turn forward the request with the District’s recommendation to the Administrator of the Office of Structural Engineering. 1002.2 General Requirements
1002.2.1 Pipe Materials
The type of pipe materials listed under the various conduit types in Section 603.02 of the Construction and Material Specifications shall be considered as equal within their size, structural and material durability limitations. 1002.2.2 Outlet Velocity Control
When permissible pipe alternates have different velocity characteristics, the design specified for erosion control shall satisfy the most severe velocity condition of the permissible alternates. In this case, “erosion control” refers to controls placed in the stream channel at the outlet end of
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the pipe such as rock channel protection, and does not refer to energy dissipater. Where the calculated culvert outlet velocity exceeds 20 feet per second or 15 feet per second in areas of poor soil such as fine sand or sandy silt, roughness elements (protruding concrete rings inside the pipe) may be specified at the outlet end of the alternates to reduce the velocity below the maximum allowable. The design of internal energy dissipator ring chambers is provided in report FHWA/OH-84/007 “Internal Energy Dissipators for Culverts”. This report and ring chamber details can be obtained from the Hydraulic Section, Office of Structural Engineering. Where the outlet velocity for a corrugated pipe is less than 20 feet per second while the outlet velocity for a smooth pipe requires a ring chamber, the corrugated pipe may be specified exclusively. 1002.2.3 Special Shapes
Special shaped conduits (elliptical concrete, corrugated metal arch or pipe arch, or prefabricated box or three-sided structures) are generally limited for use under shallow cover installations or extremely low or restrictive headwater control otherwise requiring multiple circular conduits to satisfy allowable headwater conditions. Generally elliptical concrete and corrugated metal pipe arch of the required size to satisfy hydraulic conditions are to be shown on the plan. Special shaped conduits may be provided to conform to the cross-sectional geometry of sensitive streams identified in the environmental documentation. Where corrugated metal and structural plate pipe arches are specified or permitted, a foundation investigation shall be submitted as required by Section 1008.1.5. 1002.2.4 Structure File Number
Structures having an opening measured along the centerline of roadways of 10’ or greater require a Structure File Number (SFN). Multiple openings where the extreme ends of the openings are 10’ or greater also require a SFN, where the clear distance between opening is less than half of the smaller contiguous opening.
1002.3 Conduit Types
1002.3.1 Type A Conduits
Type A conduits shall be designated for soil-tight, sealed-joint, open-ended cross drains under pavements and paved shoulders. The minimum size culvert (or cross drain) to be specified shall be based on the roadway type and depth of fill from the flowline to roadway surface. The minimum required round (or equivalent deformed) pipe sizes are listed in Figure 1002-1. For culverts under freeways or high fills (16 feet), the size shall be increased one pipe size over the required size to allow for future repair. The pipe shall only be upsized once. All hydraulically and structurally adequate pipe alternates which provide the required service life shall be shown on the plans and listed in the pertinent pay item. In the applicable size ranges, alternates should include, vitrified clay, concrete, corrugated steel, and corrugated aluminum. For corrugated metal pipe, the corrugation profile which requires the thinnest metal shall be listed. Where durability requires increased thicknesses of the corrugated steel alternate, the 1-inch corrugation profile should be specified for pipe diameters over 48 inches. For the steel corrugation profile specified, all combinations of thickness and protection providing the required service life shall be specified. If the alternates to be listed in the plan are of a different size, show the pipe length associated with the smallest pipe size. In addition to hydraulic and structural considerations, pipe material durability shall be considered in the selection of culvert materials. All Type A Conduits under State and Federal routes shall be designed to provide a minimum median service life of 50 years. At sites where the future cost to replace a pipe could be exceptionally high such as under high fills (16 feet or more from flowline to finish grade) or freeways, a design median service life of 75 years shall be used. The pH of the normal stream flow and the presence of abrasive flow conditions shall be the factors considered to determine material durability. At all sites, the pH of the normal stream flow shall be measured and a determination of the abrasive potential of the stream shall be made. The presence of granular material accompanied with a stream gradient or
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flow sufficient to cause movement of the granular material in the stream bed shall be the basis for the determination of an abrasive versus non-abrasive site for corrugated steel pipe. Granular material is considered to be a material larger than sand or pea gravel. A site should be considered abrasive for corrugated aluminum pipe if bed loads consist of sharp cobbles with flow sufficient to carry the bed load through the culvert. Otherwise, the site should be considered non-abrasive. If there is no normal stream flow during the culvert field review, Figures 1002-2 and 1002-3 may be used to determine pH. Future land use (such as coal mines) should be considered and the durability design adjusted to meet future needs. Figures 1002-4, 5 and 6 shall be used to determine the pipe materials for the design service life. These tabulations are based on the ODOT Culvert Durability Study and later reports. The equations in the referenced study can be used to determine service lives other than 50 and 75 years. The following shall govern the determination of the pH factor for the categories listed in Figures 1002-4, 1002-5 and 1002-6. 1. The instrument used to measure the pH shall
be capable of determining the pH within an accuracy of 0.1.
2. The firm or agency responsible for the
preparation of the plans shall be responsible for obtaining the pH readings.
3. A report shall be submitted, with the Drainage
Review plans, listing for all culvert sites: the pH of the stream flow, an evaluation of whether the site is abrasive or non-abrasive, and a statement that the tests were made in dry weather or low flow.
If it is known that future flow conditions will be more corrosive than existing conditions, specify protection that is greater than what is currently required. Submit documentation of the known future flow condition and additional protection with the report. 1002.3.2 Type B Conduits
Type B conduit shall be designated for soil-tight, sealed joint sewers under pavements, paved shoulders, and commercial or industrial drives. In areas with highly erodible soils (e.g., fine sands or silts), premium joints shall be provided.
Additional protection (epoxy coating as per 706.03 for concrete pipe and polymer coating per 707.04 for asphalt paved corrugated steel pipe) shall be provided for storm sewers carrying corrosive flow. Conduit placed through MSE walls or in the fill of MSE walls are limited to 706.02, as per plan, with joints per 706.11. The design service life for all Type B conduit is 100 years. No additional design considerations are required to achieve the design service life. 1002.3.3 Type C Conduits
Type C conduit shall be designated for soil-tight, sealed joint sewers not under pavements, paved shoulders, or commercial or industrial drives. In areas with highly erodible soils (e.g., fine sands or silts), premium joints shall be provided. Additional protection (epoxy coating as per 706.03 for concrete pipe and polymer coating per 707.04 for asphalt paved corrugated steel pipe) shall be provided for storm sewers carrying corrosive flow. The design service life for all Type C conduit is 100 years. No additional design considerations are required to achieve the design service life. 1002.3.4 Type D Conduits
Type D conduits shall be designated for pipes under driveways and bikeways. The minimum size required is 12 inches. For sizes 24 inches and larger, it will be necessary to submit calculations and specify pipe sizing required to satisfy the hydraulic controls. Such analyses shall be submitted with the Drainage Review plans. The design frequency used to analyze the hydraulic performance of the Type D conduit is the same as that used for the flow capacity of the connected ditch or channel and the headwater for that frequency shall not exceed a point 1 foot below the edge of the pavement. If potential exists for the drive pipe headwater to encroach on the adjacent roadway, the drive pipe shall be sized utilizing a design frequency as per 1004.2. Generally, the pipe alternates listed in 603.02 of the Construction and Material Specifications are applicable, except that equal size corrugated pipe will provide satisfactory alternates for sizes smaller than 24 inches. If the control is critical, a hydraulic analysis will be required to determine the proper size of pipe alternates.
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Drive pipes under commercial or industrial drives shall be designed for material durability as per 1002.3.1. Additional protection for residential and field drives may be specified if conditions warrant. 1002.3.5 Type E Conduits
Type E conduits shall be designated for farm drain headers inside or outside of the right-of-way lines. Headers are ordinarily provided to intercept small, closely spaced lines in a tiled field thereby precluding the need for numerous field tile outlets through the backslope of the highway ditch. 1002.3.6 Type F Conduits
Type F conduits shall be designated where a butt joint or a short length jointed pipe would be undesirable as noted below: A. For the steep portion of a median outlet under
an embankment slope 4:1 or steeper, including any necessary pipe bends.
B. For the outlets of underdrains or farm drains
through the slope or connecting to a drainage structure. When used for underdrain outlets, the following pay item description shall be used: Item 603 " Conduit, Type F for Underdrain Outlets. Provide 10 feet of conduit at each outlet into a drainage structure.
C. For farm drains larger than 12 inches that
outlet through slopes flatter than 4:1, provide a 20 foot length of Type F Conduit with an animal guard at the outlet.
D. For pipe underdrains that span the trench of a
lower conduit, unless the crossing is more than 12 inches above the granular backfill of the lower conduit, provide a minimum length of 10 feet of Type F Conduit.
Type F conduits may be used beyond the paved shoulder to eliminate a ditch in front of a yard where such ditch elimination can be justified. When required by hydraulic analysis, all proper sized alternates shall be specified. 1002.3.7 Liner Pipe
Liner pipe can be considered as a solution for culvert rehabilitation or replacement in lieu of utilizing traditional open cutting.
Specify only one size for the liner pipe in the plans. Equal consideration shall be given to all suitable pipe alternatives as listed in Supplemental Specification 837. The liner pipe shall be designed to match existing headwater conditions. Appropriate erosion control measures shall be designed for increased outlet velocities. In order to avoid a reduction in flow capacity, the selected liner pipe size shall be the one with the largest inside diameter that provides a constructible fit within the existing host pipe. A constructible fit is considered to be when the outside diameter of the liner pipe is approximately 5% smaller than the smallest inside diameter of the existing host pipe. The designer is responsible for determining the outside diameter of the liner pipe based on field measurements of the existing host pipe. If the design is unable to meet the existing headwater conditions or the outside diameter constraint described above, contact the Hydraulic Section, Office of Structural Engineering.
1003 Hydrology
1003.1 Estimation of Magnitude and Frequency of Floods on Ohio Streams
1003.1.1 General
USGS Water Resources Investigations Report 89-4126 “Techniques for Estimating Flood-Peak Discharges of Rural Unregulated Stream in Ohio” was developed cooperatively by the United States Geological Survey and the State of Ohio. This bulletin is an update of Bulletin 32 (1959), Bulletin 43 (1969), and Bulletin 45 (1977). This report provides the latest hydrologic information for determining the magnitude and frequency of floods for rural streams in Ohio. The techniques presented in Report 89-4126 shall be used to determine the design peak discharge for hydraulic structures designated by or for ODOT. When applying this technique, the tributary with the largest contributing drainage area, not the longest reach, should be considered. USGS Water Resources Investigation Report 93-4080 “Estimation of Flood Volumes and Simulation of Flood Hydrographs for Ungaged Small Rural Streams in Ohio” shall be used to determine flood volumes and hydrographs for rural areas within the limits prescribed in the report.
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1003.1.2 Limitations
The regression equations, as presented for the three geographic regions, should be used only for unregulated streams draining rural areas in excess of 6 acres. For smaller drainage areas or larger drainage areas where no well defined natural channel exists and sheet flow prevails, the rational method (Section 1101.2.2) shall be used. USGS Open File Report 93-135 "Estimation of Peak-Frequency Relations, Flood Hydrographs, and Volume - Duration - Frequency Relations of Ungaged Small Urban Streams in Ohio” shall be used in the design of culverts, detention basins, large storm sewers, and large open channels with urban drainage areas within the limits prescribed in the report. The rational method shall be used in the design of pavement inlets, roadway ditches, and small storm sewers. For additional guidance on the proper use of USGS regression equations see Transportation Research Record 1319 Report “Information Needs for the Proper Application of Hydrologic Regional Regression Equations”. Reports 89-4126, 93-4080 and 93-135 are available in limited quantities from the Hydraulic Section, Office of Structural Engineering, 1980 W. Broad Street, Columbus, Ohio 43223.
1004 Flood Clearance
1004.1 General
Where a new highway crosses or is located in a flood plain, the highway grade shall normally be set such that the low edge of the pavement will clear the design water surface profile for existing conditions by 3 feet, and bridges (low chord) will generally clear the water surface profile of the design year frequency flood. These clearances may be reduced where an economic comparison of alternatives shows that a reduction in clearance will result in significant savings, giving full consideration to future flood-related costs relative to: highway operation, maintenance, and repair; highway-aggravated flood damage to other property; and for additional or interrupted highway travel. Flood clearances may also be reduced to protect important ecological resources as identified in the environmental documentation. An economic
comparison of alternatives shall be performed to determine the future flood-related costs relative to: highway operation, maintenance, and repair; highway-aggravated flood damage to other property; and for additional or interrupted highway travel. 1004.2 Design Year Frequency
* Unless otherwise approved by the Hydraulic section, Office of Structural Engineering. 1004.3 Plan Designation
The water surface elevation, velocity of flow and peak discharge for the design, and 100-year frequency storms shall be shown on the plan and profile sheets and culvert detail sheets.
1005 Highway Encroachments on Flood Plains
1005.1 General
The requirements of the Federal Code of Regulations, Volume 23, Part 650A, shall be followed for all projects. All highways that encroach on flood plains, bodies of water or streams, shall be designed to permit conveyance of the 100-year flood without causing significant damage to the highway, the stream, body of water or other property. Special consideration must be given when designing a structure located within a reach of channel that is part of a flood insurance study managed by the Federal Emergency Management Agency (FEMA). If this condition is applicable, the proposed maximum allowable 100-year water surface elevation will generally be limited to the existing 100-year water surface elevation presented in the flood insurance study. The local FEMA floodplain coordinator must be informed of any proposed construction within the limits of a flood prone area as designated by a FEMA flood insurance study.
Freeways or other multi-lane facilities with limited or controlled access . . 50 Year
Other Highways (2000 ADT and over) and Freeway Ramps . . . . . . . . . . . 25 Year
Structures and/or channels shall be sized to satisfy the design year discharge. However, the size selected shall permit the conveyance of the 100-year flood without causing significant damage. Inundation of the highway is considered acceptable for the 100-year flood, but it is not permitted for the design-year flood. It is not necessary to lower the water surface elevation of any frequency flood below existing stages, except that the controls outlined in Section 1006.2.1 A, B and C must be satisfied. 1005.2 Type of Studies
1005.2.1 Flood Hazard Evaluation
A flood hazard evaluation is required for all water course involvements except for crossings where roadway culverts are provided to satisfy minimum size requirements. A Flood Hazard Evaluation shall entail a determination of the water surface elevation of the design year and 100-year floods by means of the procedures outlined in this section and Section 1105. Headwater pools shall be delineated on a topographic map. The valuation shall also include a discussion of the significance of any increase in the flooding limits over the existing conditions. Additional information regarding Flood Hazard Evaluations for cast-in-place or bridge structures may be obtained in the Bridge Design Manual. 1005.2.2 Detailed Flood Plain Study
If the Flood Hazard Evaluation should indicate a significant increase in the flooding of upstream property, a Detailed Flood Plain Study will be required. A Detailed Flood Plain Study should also be performed in highly urbanized areas where the potential for flooding cannot be accurately assessed without an analysis of the entire flood plain. For prefabricated structures, the Detailed Flood Plain Study, including a step-backwater analysis, will be authorized after review of the Flood Hazard Evaluation, by the Hydraulic Section, Office of Structural Engineering. Additional information regarding Detailed Flood Plain Studies for bridges or cast-in-place structures may be obtained in the Bridge Design Manual.
1006 Culvert Allowable Headwater
1006.1 Design Storm
The frequency of the design storm shall be as stated in Section 1004.2. 1006.2 Controls
1006.2.1 Design Storm Controls
Headwater depth for all culverts (Type A Conduits) shall not exceed any of the following controls for the design storm: A. 2 feet below the near, low edge of the
pavement for drainage areas 1000 acres or greater and 1 foot below for culverts draining less than 1000 acres.
B. 2 feet above the inlet crown of the culvert or
above a tailwater elevation that submerges the inlet crown in flat to rolling terrain.
C. 4 feet above the inlet crown of a culvert in a
deep ravine. D. 1 foot below the near edge of pavement for
bicycle pathways. 1006.2.2 Check Storm Controls
Headwater depth for all culverts (Type A Conduits) shall not exceed any of the following controls for the applicable check frequency storm. A. 2 feet below the lowest ground elevation
adjacent to an occupied building for a 50-year storm (it is not intended, however, to lower existing highwater elevations around buildings).
B. The designer should generally limit the
maximum 100-year headwater depth to twice the diameter or rise of the culvert.
C. A replacement structure should be sized to
prevent overtopping by the 100-year flood where such overtopping would not occur with the existing structure.
D. A replacement structure should be sized such
that flooding of upstream productive land is not increased for the 100-year flood when compared to the existing structure. Judgment shall be used in implementing this
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policy, considering the type of upstream property and sensitivity to the accuracy of the computed flood stages.
E. No significant increase in 100-year headwater
elevation shall occur in a FEMA designated floodway.
1006.2.3 Local Floodplain Coordinator
The local floodplain coordinator should be contacted early in the design process to determine the allowable headwater increase and or the permitting requirements. A current list of floodplain coordinators can be found at: http://www.dnr.state.oh.us/water/floodpln/communitylist.pdf.
1006.2.4 Limitations
1006.2.1 B and C; and 1006.2.2 B, C and E are arbitrary headwater controls. When 1006.2.1 B is applicable, use smooth pipe to establish the allowable headwater in feet. When 1006.2.1 C controls, use corrugated pipe to establish the headwater and thereby permit the same headwater elevation regardless of type of pipe. More heading will be considered if pipe sizes can be reduced and not cause damaging upstream flooding or excessive outlet velocity. 1006.2.1 B and C are arbitrary controls that apply generally to small culverts. Where large structures (greater than or equal to 10 feet in span) are involved, the structure should be sized to pass the design storm while maintaining a free water surface through the structure. The near low edge of pavement is the location where roadway overtopping will occur. This may or may not be located directly over the culvert. Where the overtopping point on the roadway is outside the watershed break, the ditch break overflow elevation should be utilized as a headwater control in lieu of 1006.2.1 A.
1007 Pipe Removal Policy
1007.1 General
Use the following guidelines to determine whether an existing pipe, regardless of type, being taken out of service should be abandoned or removed. A. Pipes 8 inches in diameter or rise, or less,
regardless of depth or height of fill, may be abandoned in place.
B. Pipes 10 inches through 24 inches in
diameter or rise with less than 3 feet of final cover should be removed or filled; with more than 3 feet of final cover they may be abandoned in place. (The designer should use discretion in removing small pipes under existing rigid pavement or base, which is to remain in place.)
C. Pipes over 24 inches in diameter or rise
should generally be removed. (The designer should use discretion in removing any pipe with more than 10 feet of cover.)
1007.2 Asbestos pipe
Asbestos pipe is a regulated material. Designers should make reasonable efforts to identify existing asbestos pipes in the plans and, when necessary, provide appropriate removal quantities. In the past, pipe containing asbestos was allowed on ODOT, LPA and utility projects under the following specifications:
Transite is a common brand name for a type of asbestos pipe. Asbestos can also be found in insulation wrapped around water pipes.
Reasonable efforts to identify asbestos pipes would include the following: A. Examination of original construction plans
and specifications. B. Contact with the owner of the pipe (e.g., utility
company or LPA). C. Inspection of the pipe for markings when the
pipe is exposed during routine maintenance operations.
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Removal of asbestos pipe is specified as Item 202 Asbestos Pipe Removed in the 2005 CMS. For projects to be constructed under the 1997 CMS, use Item 202 Pipe Removed, As Per Plan and indicate that the pipe must be removed by a certified asbestos contractor. Asbestos is a hazard only when it becomes airborne. Pipes that are otherwise unaffected by ODOT work do not need to be removed simply because they contain asbestos. Not all asbestos pipe will be identified by a records search. Construction inspectors are being advised to test suspicious pipe for asbestos. If asbestos pipe is identified, the contractor will be compensated by change order.
1008 Structural Design Criteria
1008.1 Corrugated and Spiral Rib Steel and Aluminum Pipes, and Corrugated Steel and Aluminum Pipe Arches
1008.1.1 Material Durability
The policy outlined in Section 1002 specifying types of protective coatings and/or extra metal thickness shall be followed. 1008.1.2 Designation and Thickness
The corrugation profile and required metal thickness shown in Figures 1008-1 through 1008-6 and 1008-15 through 1008-19 shall be specified. The thickness should be determined for the maximum height of cover and it shall be used for the full length of the structure. However, where a short length of conduit requiring a higher strength pipe is contiguous with a long run of pipe, then only that short length should be specified as requiring the higher strength pipe. Generally, the corrugation profile requiring the thinnest metal for a given size conduit shall be specified. When the minimum thickness shown in these figures will suffice, the thickness need not be specified. The preferred corner radius for structural plate corrugated pipe arches is 31”. The commercial availability of a specific sheet thickness for various pipe diameters should be verified. Use the General Notes for Figures 1008-1 through 1008-9, General Notes for Figures
1005-15 through 1008-21, and the Height of Cover Tables for this purpose. Minimum sheet thicknesses for the various corrugation profiles and pipe diameters are tabulated in the pertinent 700 Section of the Construction and Material Specifications Handbook. 1008.1.3 Cambered Flow Line
Where soil conditions at the site indicate that appreciable settlement is expected, provide a cambered flow line. Show the cambered flow line as a vertical curve. 1008.1.4 Height of Cover
See General Notes for Figures 1008-1 through 1008-9 and 1008-15 through 1008-21 1008.1.5 Foundation Reports
An investigation of the supporting foundation material shall be conducted and the bearing capacity of the foundation material estimated. Submit the foundation report for all proposed pipe arch installations with the Stage 1 review. Refer to section 1008.9 for information on foundation types. 1008.1.6 Corner Bearing Pressures
The tables of corner bearing pressures (Figures 1008-7, 1008-8, 1008-9, 1008-20 and 1008-21) are for installations with 4 feet or less cover. The minimum height of cover requirements for pipe arch shapes, from Section 1008.1.4 shall be satisfied. The corner bearing pressures listed for cover less than the minimum are for information only. 1008.2 Rigid Pipe
1008.2.1 General
Height of cover tables are shown in Figures 1008-10 through 1008-13. Information on the use of these tables can be found in the General Notes for Figures 1008-10 through 1008-14. Where soil conditions at the site indicate that appreciable settlement is expected, provide a cambered flow line. Show the cambered flow line as a vertical curve. .
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The minimum D-Load for the various diameters of reinforced concrete pipes are tabulated in Section 706.02 of the Construction and Material Specifications Handbook. 1008.2.2 Height of Cover
The maximum allowable height of cover is measured from the top of the pipe to the pavement surface. The minimum cover, from the top of the pipe to the top of the subgrade, or finish grade for pipe not under pavements, is 9 inches; however, in no installation shall the distance from the top of the pipe to the pavement surface be less than 15 inches. 1008.2.3 Structural Design Criteria
The following criteria are to be considered when determining pipe characteristics. A. The maximum allowable height of cover,
listed in the tables, is based on structural requirements for dead and live loads assuming an ordinary soil foundation. Where a rock or unyielding foundation is encountered in an embankment installation, additional thickness of granular bedding and/or greater strength pipe may be required. The extent of increase necessary is related to pipe size and cover.
B. Where the type of pipe is circular, reinforced
concrete pipe (706.02) and the height of cover exceeds the maximum cover listed in the Height of Cover Tables for a specific size and installation type, the pipe should still be included in the project plans. The concrete pipe alternate should be specified as 706.02 with special design.
The special design will be provided by the manufacturer after the project letting.
C. If the height of cover over a pipe exceeds 100
feet, a special design is required to investigate foundation suitability.
D. The required pipe strength should be
determined for the maximum height of cover and it shall be used for the full length of the pipe. However, where a short length of conduit requiring a higher strength pipe is contiguous with a long run of pipe, then only that short length should be specified as requiring the higher strength pipe.
1008.3 Thermoplastic Pipe
1008.3.1 Height of Cover
The maximum allowable height of cover is measured from the top of the conduit to the pavement surface or to finished grade for pipes not under pavement. The maximum height of cover should be limited to 20 feet. Cover greater than 20 feet may be provided contingent upon the approval of the Hydraulic Section, Office of Structural Engineering. The minimum cover, from the top of the pipe to the top of the subgrade, is 12 inches; however, in no installation shall the distance from the top of the pipe to the pavement surface, or finish grade for pipes not under pavement, be less than 18 inches. 1008.4 Corrugated Steel and Aluminum Box Culverts and Corrugated Steel Long Span Culverts.
1008.4.1 Designation and Thickness
The corrugation profile and metal thickness required shall be in accordance with the AASHTO LRFD Bridge Design Specifications design methodologies. The Hydraulic Section, Office of Structural Engineering is responsible for the structural design of all corrugated steel and aluminum box culverts, and corrugated steel long span culverts. The skew of the structure relative to the roadway shall be given in 1° increments and typically should not exceed 15°. 1008.4.2 Height of Cover
The minimum and maximum heights of cover shall be in accordance with the AASHTO LRFD Bridge Design Specifications design methodologies. However, in no case shall the minimum cover, measured from the trough of the corrugation profile to the pavement surface, be less than 18 inches. In addition to the above requirements, corrugated steel and aluminum box culverts shall be provided with adequate cover to ensure that the culvert rib stiffeners are located completely within the subgrade. 1008.4.3 Foundation Reports
Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the
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foundation report for all proposed metal box and long span culvert installations with the Stage 1 review. 1008.5 Precast Reinforced Concrete Box Culverts
1008.5.1 Designation
The allowable sizes of Precast reinforced concrete box culverts shall be as given in Figure 1008-14. The pay item description shall include the height of cover (design earth cover), rounded to the highest 1 foot. Structures with a span of 12 feet or less shall be designed as per ASTM C 1577. Structures with spans 14 feet or greater require a special design available from the Hydraulic Section, Office of Structural Engineering. 1008.5.2 Height of Cover
The maximum allowable height of cover is measured from the top of the culvert to the pavement surface. The maximum height of cover shall be as per Figure 1008-14. Greater covers may be provided contingent upon the approval of the Hydraulic Section, Office of Structural Engineering. A special design is required. 1008.5.3 Structural Design Criteria
The design loading information shall be included on the Culvert Detail Sheet or Site Plan. Structures with spans 14 feet or greater are designed with the HL-93 loading. A 60 psf future wearing surface is included in the dead loading only for structures with spans 14’ or greater. 1008.6 Precast Reinforced Concrete Three-Sided Flat-Topped Culverts
1008.6.1 Designation
Precast reinforced concrete three-sided, flat -topped culverts shall have a minimum clear span of 14 feet and minimum opening rise of 4 feet; and a maximum clear span of 34 feet and maximum opening rise of 10 feet. The individual culvert units may be skewed in 5° increments with a maximum skew of 30°. Designate the skew of the structure relative to the
roadway in 1° increments with a maximum skew of 30°. The minimum deck thickness for the culvert units is 12 inches and the minimum leg thickness for the culvert units is 10 inches. The design should be based on these dimensions. 1008.6.2 Height of Cover
The maximum allowable height of cover is measured from the top of the culvert to the pavement surface. The maximum height of cover should be limited to 10 feet. Cover greater than 10 feet may be provided contingent upon the approval of the Hydraulic Section, Office of Structural Engineering. 1008.6.3 Structural Design Criteria
Design Flat-topped, three-sided culverts in accordance with AASHTO LRFD Bridge Design Specifications design methodologies. The design loading information (HL-93) shall be included on the Culvert Detail Sheet or Site Plan. Spans greater than 12 feet shall have an additional load of 60 psf to allow for future roadway resurfacing. 1008.6.4 Foundation Reports
Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all proposed flat-topped, three-sided culvert installations with the Stage 1 review. Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans. Refer to section 1008.9 for information on foundation types. 1008.7 Precast Reinforced Concrete Arch Sections
1008.7.1 Desi gnation
Precast reinforced concrete arch sections have a clear span of 12, 14, 16, 20, 24, 28, 32, 36 or 42 feet and an opening rise of 4 feet through 13 feet (maximum). Other sizes, including spans of 48, 54 and 60 feet, are contingent upon the approval of a public interest finding through the Hydraulic
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Section, Office of Structural Engineering and the Federal Highway Administration. Designate the skew of the structure relative to the roadway in 1° increments with a maximum skew of 30°. Individual culvert sections may only be skewed with written permission from the Office of Structural Engineering. Obtain the deck thickness and leg thickness for the culvert units from the manufacturer. Show the maximum and minimum cover on the plans. Design the footing keyway based on the leg thickness plus 6 inches. Design the guardrail post length based on the deck thickness and cover. 1008.7.2 Height of Cover
The maximum allowable height of cover is measured from the top of the culvert to the finished surface. The maximum height of cover is limited to 12 feet. Cover greater than 12 feet may be provi ded contingent upon the approval of the Hydraulic Section, Office of Structural Engineering. The minimum cover, from the top of the arch sections to the top of the pavement is 12 inches. However, in no case shall the top of the arch sections be located above the top of subgrade. 1008.7.3 Structural Design Criteria
Precast Reinforced Concrete Arch Sections are designed in accordance with AASHTO LRFD Bridge Design Specifications design methodologies. Show the design loading information (HL-93) with the additional load of 60 psf for spans greater than 12 feet on the Culvert Detail Sheet or Site Plan. 1008.7.4 Foundation Reports
Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all precast reinforced concrete arch section culvert installations with the Stage 1 review. Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans. Refer to section 1008.9 for information on foundation types.
1008.8 Precast Reinforced Concrete Round Sections
1008.8.1 Designation
Precast reinforced concrete round sections are one or two piece structures with a clear span of 12, 16, 20, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78 and 84 feet available in various rises and shapes. Specific sizes and designs are approved by the Office of Structural Engineering. Designate the skew of the structure relative to the roadway in 1° increments with a maximum skew of 30°. Individual culvert sections may only be skewed with written permission from the Office of Structural Engineering. Obtain the section thickness for the sections from the manufacturer. Show the maximum and minimum cover on the plans. Design the footing keyway based on the section thickness plus 8 inches. Design the guardrail post length based on the section thickness and cover. Precast reinforced concrete round sections may only be used for roadway grade separation structures with written approval from the Office of Structural Engineering. Standard design modifications, including but not limited to increased concrete thickness, concrete admixtures, epoxy coating of concrete surfaces and epoxy coating of reinforcing steel may be required for approval for use as roadway grade separation structures. 1008.8.2 Height of Cover
The maximum allowable height of cover is measured from the top of the round sections to the finished surface. The maximum height of cover is limited to 12 feet. Cover greater than 12 feet may be provided contingent upon the approval of the Hydraulic Section, Office of Structural Engineering. The minimum cover, from the top of the round sections to the top of the pavement is 12 inches. However, in no case should the top of the arch sections be located above the top of subgrade. 1008.8.3 Structural Design Criteria
Design Precast Reinforced Concrete Round Sections in accordance with AASHTO LRFD Bridge Design Specifications design methodologies.
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April 2010 10-12
For all spans, show the design loading information (HL-93) with the additional load of 60 psf on the Culvert Detail Sheet or Site Plan. 1008.8.4 Foundation Reports
Conduct an investigation of the supporting foundation material and estimate the bearing capacity of the foundation material. Submit the foundation report for all precast reinforced concrete round section installations with the Stage 1 review. Include with the foundation report a letter from the manufacturer stating the reactions for foundation design. Show the footing and/or pedestal wall vertical and horizontal unfactored reaction forces in the plans. Refer to section 1008.9 for information on foundation types. 1008.9 Foundations
Arch or flat slab topped culverts are supported on either spread footings or deep foundations such as piles or drilled shafts. Provide a spread footing founded a minimum of 4 feet below the flowline on competent, scour resistant native soils when there is no evidence of stream scour or degradation. Calculate scour per the equation: Ymax = 1.7613 * (Q / 11.17 * wculv * D50soil
1/3) 6/7 Where, Ymax = maximum scour (ft) Q = volumetric flow (ft3/sec) wculv = width of the culvert inlet (ft) D50soil = sediment size (ft) When scour is 10 feet or less, contact the Office of Structural Engineering, Hydraulics Section for possible use of a paved bottom and/or cutoff walls. Provide a deep foundation if the scour depth is 3 feet below the footing. Provide Rock Channel Protection for all scour prone excavated areas sized per the equation:
D50rock = y0 (0.23)(vac
2 / g * y0) 0.33
Where,
D50rock = riprap median size (ft) y0 = depth of flow in the approach to
the culvert before scour (ft) vac = average velocity in the
contracted zone prior to scour in the vicinity of the upstream corner of a culvert (ft/sec)
g = 32.2 (ft/sec2)
Use Type C Rock Channel Protection as a minimum. Provide a cost comparison justification study between alternative structure types, including bridges, when utilizing a deep foundation. Submit the cost comparison justification study to the Hydraulics Section, Office of Structural Engineering. Provide a keyway in the foundation to set the arch or flat slab topped culverts into. The width of the keyway is a minimum of 6 inches wider than the precast leg (3 inches on both sides of the leg). The depth of the keyway is a minimum of 3 inches. 1008.10 Waterproofing Membrane
Apply an external waterproofing membrane to all precast reinforced concrete box culverts, three-sided flat-topped culverts, arch culverts and round sections. Use Item 512 Waterproofing, Type 2 along the vertical sides and Type 2 or 3 across the top of the structure. Type 3 waterproofing shall be used if pavement is to be used directly on top of the structure. Provide an overlap of a minimum of 12 inches of the top membrane to the vertical membrane. 1008.11 Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops
Precast Reinforced Concrete Flat Slab Tops, Catch Basin Tops, and Inlet Tops shall be designed in accordance with ASTM C478. When the structure is under pavement and the span is greater than 10 feet the design loading for the structural design shall be HL-93. 1008.12 Wingwall Design
When not using the standard construction drawings or design data sheets, design wingwalls in accordance to the current AASHTO LRFD
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Bridge Design Specifications. Assume no passive forces are acting on the toe of the wall.
1009 Subsurface Pavement Drainage
1009.1 General
Subsurface pavement drainage is required on all projects. An exception may be made where the project is located in an area having a granular subgrade. The subsurface drainage design shall be submitted with the Preliminary Drainage review for approval. 1009.2 Types of Subsurface Drainage
There are three means of draining the pavement subsurface - pipe underdrains, prefabricated edge drains, and aggregate drains. Generally, pipe underdrains are used with paved shoulders and curbed pavements (Figures 1009-1 through 1009-7). Prefabricated edge drains are typically used where existing concrete pavement with paved shoulders are to remain. Aggregate drains are used with bituminous surface treated shoulders, aggregate shoulders, and for spot improvements (Figures 1009-8 and 1009-9). Additional examples of typical underdrain and edge drain placements can be found in the Sample Plan Sheets. 1009.2.1 Pipe Underdrains
Pipe underdrains are used on both sides of the pavement and are typically carried through superelevated sections. The maximum pavement width for each pipe underdrain is 24 feet. Figures 1009-1 through 1009-7 show locations for pipe underdrains with respect to several shoulder designs. Pipe underdrains generally follow the profile grade of the roadway as long as the pipe underdrain maintains a positive or zero slope. For these cases, hydrostatic pressure is sufficient to ensure the proper drainage of the subbase and subgrade. Underdrain depth is measured from the bottom of subbase to the bottom of the underdrain trench. Base pipe and shallow pipe underdrains are typically 4-6 inches in diameter. The 4 and 6 inch underdrains are considered equivalent in hydraulic capacity for the base pipe and shallow pipe underdrains. Use a 6 inch underdrain if the outlet interval is greater than the desired interval of 500 feet or if the subgrade is saturated. Specify the material if using a 6” pipe underdrain.
Base pipe underdrain has a constant depth of 18 inches or less and the shallow pipe underdrain has a depth greater than 18 inches with a maximum of 30 inches. Where a dual underdrain system is provided (shoulder greater than or equal to 8 feet), the edge of shoulder underdrain is supplemental to the edge of pavement underdrain and is typically a base pipe underdrain with a depth of 18 inches. Rock cut underdrains are used in cut sections when a rock, shale, or coal subgrade exists. The depth of the rock cut underdrain should be 6 inches below the cut surface of the rock (Figure 1009-10). Deep pipe underdrains have a constant depth greater than 30 inches with the preferred maximum depth at 50 inches below subbase. These are typically 6 inches in diameter. Deep pipe underdrains are used in cut sections, or areas with a high water table, to drain the subgrade. Unclassified underdrains are those having a variable depth below profile grade within a single continuous longitudinal run. Variable depth pipe underdrains (unclassified) shall be avoided where pipe underdrains of a constant depth can be provided. Underdrains which outlet to a slope should be provided with an outlet per SCD DM-1.1. Underdrain outlets should be provided at a desirable interval of 500 feet with a maximum interval of 1000 feet. Underdrain outlets should be provided at a desirable interval of 300 feet, with a maximum interval of 500 feet, where free draining base is utilized. It is desirable to outlet underdrains at least 12 inches above the flowline of a receiving ditch; and 12 inches above the flowline of a receiving catch basin, manhole, or pipe with 6 inches as a minimum. Underdrain outlets shall be type F conduit. When underdrain spans the trench of a lower conduit (utility, storm sewer, culvert, etc.) and the vertical distance between the trench and underdrain is less than or equal to 12 inches, a type F conduit should be used to span the lower trench. Use a minimum of 10 feet. A fabric filter wrap should be used when existing soils consist of a sandy or sandy-silt composition. Where necessary, the depth of the underdrains may vary slightly. Underdrain outlet pipe
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outletting into a roadway ditch or fill slope should maintain a minimum slope of 1%. Outlets should not be located at the top of high (over 20 feet) 2:1 fill slopes. If this cannot be accomplished by adjusting the spacing, special outlet treatments will be required. 1009.2.2 Construction Underdrains
In fine-grained soils excess water in the subgrade is the principal cause of unstable soil conditions during construction. Adequate subgrade drainage can be achieved by using temporary pipe underdrains. These underdrains are sacrificial in nature and are intended to work throughout the construction process. Construction Underdrains are usually placed in the centerline of the roadway. They may also be placed in the ditch line, if the water is coming in from a cut section at a higher elevation. The outlets for the construction underdrains are the same pipe material and backfill as construction underdrains (not Type F). The outlets should be discharged into a catch basin, manhole, pipe, or ditch. If discharging into a ditch, a precast concrete reinforced outlet is not required. 1009.2.3 Prefabricated Edge Drains
Prefabricated edge drains are located at the edge of existing concrete pavement on resurfacing projects where the existing pavement and paved shoulders are being retained. If existing paved shoulders are being replaced, a 4 inch shallow pipe underdrain at the edge of pavement shall be used in lieu of the prefabricated edge drain. 1009.2.4 Aggregate Drains
Aggregate drains should be located at 50 foot intervals on each side of the pavement and staggered so that each drain is 25 feet longitudinally apart from the adjacent drain on the opposite side. If used on rigid pavements, the drains shall be located at each end of each transverse joint. For superelevated pavements, the drains should be located on the low side only, at each transverse joint in rigid pavement and at 25 foot intervals for other pavement. Figures 1009-8 and 1009-9 show aggregate drains for several treated shoulder designs.
1000 Drainage Design Policies – List of Figures
April 2010
Figure Subject 1002-1 Minimum Culvert Sizes 1002-2 Water pH Contours - Average for Counties 1002-3 Water pH Contours - Values of Individual Culverts 1002-4 Requirements for Concrete Pipe Protection General Notes for Figures 1002-5 and 1002-6 1002-5(50) Requirements for Corrugated Metal Pipe Thickness and Protection at Non-Abrasive Sites - 50-year Design Service Life 1002-5(75) Requirements for Corrugated Metal Pipe Thickness and Protection at Non-Abrasive Sites - 75-year Design Service Life 1002-6(50) Requirements for Corrugated Metal Pipe Thickness and Protection at Abrasive Sites - 50-year Design Service Life 1002-6(75) Requirements for Corrugated Metal Pipe Thickness and Protection at Abrasive Sites - 75-year Design Service Life General Notes for Figures 1008-1 through 1008-9 1008-1 Height of Cover - Corrugated Steel Pipe 1008-2 Height of Cover - Corrugated Steel Pipe Arches 1008-3 Height of Cover - Structural Plate Corrugated Steel Pipe 1008-4 Height of Cover - Structural Plate Corrugated Steel Pipe Arches (18-inch [450 mm] Corner Radius) 1008-5 Height of Cover - Structural Plate Corrugated Steel Pipe-Arches (31-inch [775 mm] Corner Radius) 1008-6 Height of Cover - Corrugated Steel Spiral Rib Pipe 1008-7 Corner Bearing Pressure - Corrugated Steel Pipe Arches 1008-8 Corner Bearing Pressure - Structural Plate Corrugated Steel Pipe Arches (18-inch [450 mm] Corner Radius) 1008-9 Corner Bearing Pressure - Structural Plate Corrugated Steel Pipe Arches (31-inch [775 mm] Corner Radius) General Notes for Figures 1008-10 through 1008-14 1008-10 Maximum Allowable Height of Cover - Reinforced Concrete Pipe with Type 2 Bedding 1008-11 Maximum Allowable Height of Cover - Reinforced Concrete Pipe with Type 3 Bedding
April 2010
Figure Subject 1008-12 Maximum Allowable Height of Cover - Reinforced Concrete Elliptical Pipe
with Type 2 Bedding 1008-13 Maximum Allowable Height of Cover - Non-Reinforced Rigid Pipe with Type 2 Bedding 1008-14 Maximum Allowable Height of Cover - Reinforced Concrete Box Culvert with Type 1 bedding General Notes for Figures 1008-15 through 1008-21 1008-15 Height of Cover - Corrugated Aluminum Pipe 1008-16 Height of Cover - Corrugated Aluminum Pipe Arches 1008-17 Height of Cover - Structural Plate Corrugated Aluminum Pipe 1008-18 Height of Cover - Structural Plate Corrugated Aluminum Pipe Arches 1008-19 Height of Cover - Corrugated Aluminum Spiral Rib Pipe 1008-20 Corner Bearing Pressure - Corrugated Aluminum Pipe Arches 1008-21 Corner Bearing Pressure - Structural Plate Corrugate Aluminum Pipe Arches 1009-1 Typical Pipe Underdrain Locations 1009-2 Typical Pipe Underdrain Locations 1009-3 Typical Pipe Underdrain Locations 1009-4 Typical Pipe Underdrain Locations 1009-5 Typical Pipe Underdrain Locations 1009-6 Typical Pipe Underdrain Locations 1009-7 Typical Pipe Underdrain Locations 1009-8 Typical Aggregate Drain Locations 1009-9 Typical Aggregate Drain Locations 1009-10 Typical Rock Cut Underdrain
General Notes – Figures 1002-5 and 1002-6
April 2010
Tables 1002-5(50) & 1002-5(75) Tables 1002-5(50) and 1002-5(75) are based on equations 6 and 8 from the ODOT Location & Design publication 82-1, “Culvert Durability Study” including: • A 15-year service life for Bituminous Coating
with Invert Paving for culverts 54” and larger. • A 25-year service life for Bituminous Coating
with Invert Paving for culverts 48” and smaller.
• A 35-year service life for Aluminium Coating
with pH above 5.0 • A 50-year service life for Polymeric Coating • All base metal must provide a minimum of 10
years of service life. Corrugated aluminium alloy pipe (707.21 and 707.22) and aluminium alloy structural plate pipe (707.23) are acceptable with the minimum thickness required to satisfy cover conditions for all non-abrasive sites with a pH between 5.0 and 9.0 A blank space in the table indicates that a gage, which satisfies the design service life, is not available. Tables 1002-6(50) & 1002-6(75) Tables 1002-6(50) and 1002-6(75) are based on equations 7 and 9 from the ODOT Location & Design publication 82-1, “Culvert Durability Study” including: • A 15-year service life for Bituminous Coating
with Invert Paving for culverts 54” and larger. • A 25-year service life for Bituminous Coating
with Invert Paving for culverts 48” and smaller.
• A 35-year service life for Aluminium Coating
with pH above 5.0. • A 50-year service life for Polymeric Coating • All base metal must provide a minimum of 10
years of service life.
Corrugated aluminium alloy pipe (707.21 and 707.22) with Concrete Field Paving and
aluminium alloy structural plate pipe (707.23) with Concrete Field Paving are acceptable with the minimum thickness required to satisfy cover conditions for all abrasive sites with a pH between 5.0 and 9.0 A blank space in the table indicates that a gage, which satisfies the design service life, is not available. Abbreviations and Symbols * Concrete field paving shall be epoxy
coated per 706.03 for pH < 5.0 ** Externally coated per AASHTO M243 w/CFP With concrete field paving of invert
General Notes - Figures 1008-1 through 1008-9
April 2010
Thickness The following table shows the available commercial thicknesses for metallic coated steel and the corresponding gage number:
0.064 16
0.079 14
0.109 12
0.138 10
0.168 8
0.188 7
0.218 5
0.249 3
0.280 1
The maximum available sheet thickness for aluminum coated corrugated steel pipe (707.01, 707.02, 707.05, 707.07; all with aluminum coating) or polymer coated corrugated steel pipe (707.04) is 0.138. Minimum Cover The minimum cover is measured from the top of the pipe or pipe-arch to the top of subgrade; however, in no installation shall the distance from the top of the pipe or pipe-arch to the top of the wearing surface or finished grade be less than the figure values plus 6 inches. Maximum Cover The maximum height of cover is measured from the top of the pipe or pipe-arch, to the top of the wearing surface. When a dashed line is shown in any column, the pipe shown in the corresponding row shall not be specified for the thickness indicated. The maximum height of cover over any pipe is 100 feet, without a special design. Before a pipe is used under a cover exceeding 100 feet, the structural maximum allowable height of cover and the required bearing pressure should be calculated and an investigation of the bearing capacity of the foundation material performed. Parameters The figures are based upon the following parameters:
A. A standard highway loading of HS 20-44 for
live load. B. Unit weight of embankment material = 120
pounds per cubic foot. C. Factor of safety for seam strength = 3.0 (for
707.03) D. Factor of safety for buckling = 2.0 E. Horizontal soil modulus =1400 pounds per
square inch Foundation For all pipe-arch installations, the foundation material shall be investigated to determine its bearing capacity. The bearing capacity shall be a minimum of twice the corner bearing pressure. Seam Fabrication Allowable heights of cover are based upon the following types of seam fabrication: A. 707.01, 707.02, 707.04, 707.05, 707.07,
707.11, 707.13, and 707.14 conduits have helical continuous welded seams or helical lock seams.
B. 707.03 pipes and pipe-arches; all sizes and
wall thicknesses with four bolts per foot of seam (3/4" diameter), also the 0.280" wall thickness in all sizes with six bolts per foot of seam. If six bolts per foot of seam is required, the number of bolts per foot of seam (6) [spacing of bolts shall be specified on the plans.
C. 707.12 pipes; all sizes and wall thicknesses
with lock seams. Abbreviations and Symbols 20+ [6+] The maximum allowable height
of cover over any pipe-arch is 20' without a special design. The plus sign indicates the pipe-arch is structurally safe under a cover greater than 20', but the bearing capacity of the foundation may not be adequate.
Ht. height, in feet (ft.)
Metal Thickness Inches
Gage Number
April 2010
CBP corner bearing pressure, in tons per square foot (tsf)
b/ft. bolts per foot of seam Inv. invalid. Indicates the values were invalid
for the pipe-arch. The corner bearing pressure for the pipe-arch will always exceed the given value under any allowable height of cover.
tsf tons per square foot
General Notes - Figures 1008-10 through 1008-14
April 2010
Minimum Cover See Section 1008.2.2 Maximum Cover The maximum height of cover is measured from the top of the pipe or elliptical pipe to the top of the wearing surface. When a dashed line is shown in any column, the pipe shown in the corresponding row shall not be specified for the D-Load indicated. When an asterisk is shown in any row, the minimum strength pipe commercially available is greater than the strength shown in the corresponding column. When a blank space is shown, the pipe may be specified if a special design, verifying the structural height of cover, is provided. The maximum height of cover over any pipe is 100 feet, without a special design. Before a pipe is used under a cover exceeding 100 feet, the structural maximum allowable height of cover and the required bearing pressure should be calculated and an investigation of the bearing capacity of the foundation material performed. Abbreviations and Symbols D-LOAD The supporting strength of a pipe
loaded under three-edge-bearing test conditions expressed in pounds per linear foot per foot of inside diameter or span [Newton’s per linear meter per millimeter of inside diameter or span].
HE Horizontal elliptical reinforced concrete
pipe VE Vertical elliptical reinforced concrete pipe Precast Reinforced Concrete Box Design Loading Spans above 12' shall be designed as per section 1008.5.3.
1008-10
BEDDING REINFORCED CONCRETE PIPE WITH TYPE 2
MAXIMUM ALLOWABLE HEIGHT OF COVER FOR
Reference Section1008.2.1
706.02 Pipe-Minimum Test Load to Produce a 0.01-Inch Crack D-Load
* Contact Office of Structural Engineering for heights of fill greater than those listed above.
Side wall, top and bottom thickness is equalivent to the span in inches with the maximum being 12 inches.
General Notes - Figures 1008-15 through 1008-21
Thickness The following table shows the available commercial metal thicknesses for aluminum pipe
0.060 0.100
0.075 0.125
0.105 0.150
0.135 0.175
0.164 0.200
0.225
0.250
Minimum Cover The minimum cover is measured from the top of the pipe or pipe arch to the top of subgrade; however, in no installation shall the distance from the top of the pipe or pipe arch to the top of the wearing surface or finished grade be less than the figure values plus 6 inches. Maximum Cover The maximum height of cover is measured from the top of the pipe or pipe arch to the top of the wearing surface. When a dashed line is shown in any column, the pipe shown in the corresponding row shall not be specified for the thickness indicated. The maximum height of cover over any pipe is 100 feet, without a special design. Before a pipe is used under a cover exceeding 100 feet, the structural maximum allowable height of cover and the required bearing pressure should be calculated and an investigation of the bearing capacity of the foundation material performed. Parameters The figures are based upon the following parameters: A. A standard highway loading of HS 20-44 for
live load. B. Unit weight of embankment material = 120
pounds per cubic foot. C. Factor of safety for seam strength = 3.0
D. Factor of safety for buckling = 2.0 E. Horizontal soil modulus =1400 pounds per
square inch Foundation For all pipe arch installations, the foundation material shall be investigated to determine its bearing capacity. The bearing capacity shall be a minimum of twice the corner bearing pressure. Seam Fabrication Allowable heights of cover are based upon the following types of seam fabrication: A. 707.21 pipes; 12" dia. through 36" dia. with
one row of rivets; 42" dia. through 84" with two rows of rivets.
B. 707.21 pipe arches; 17" X 13" through 42" X
29" with one row of rivets; 49" X 33" through 83" X 57" with two rows of rivets.
C. 707.22 pipes and pipe arches; all sizes with
two rows of rivets. D. 707.23 pipes and pipe arches; all sizes and
wall thicknesses with four bolts per nine inches of seam (3/4" diameter bolts).
E. 707.24 pipes; all sizes and wall thicknesses
with lock seams. F. Spot welded, helical butt welded and lock
seams are considered equal to the seam strength of riveted seams.
Abbreviations and Symbols 20+ [6+] The maximum allowable height
of cover over any pipe-arch is 20' without a special design. The plus sign indicates the pipe-arch is structurally safe under a cover greater than 20', but the bearing capacity of the foundation may not be adequate.
Ht. height, in feet (ft.) CBP corner bearing pressure, in tons per
square foot (tsf) b/ft. bolts per foot of seam
Metal Thickness Inches
707.21, 707.22 & 707.24
Metal Thickness Inches 707.03
April 2010
Inv. invalid. Indicates the values were invalid for the pipe-arch. The corner bearing pressure for the pipe-arch will always exceed the given value under any allowable height of cover.
1102 Open Water Carriers ............................................................................................................11-3 1102.1 General..................................................................................................................11-3 1102.2 Types of Carriers ....................................................................................................11-3
1102.2.1 Standard Roadway (Roadside) Ditches .....................................................11-3 1102.2.2 Special Ditches ........................................................................................11-3 1102.2.3 Median Ditches ........................................................................................11-4 1102.2.4 Channel Relocations ................................................................................11-4 1102.2.5 Channel Linings and Bank Stabilization .....................................................11-4
1105.4.1 General ................................................................................................. 11-17 1105.4.2 Hydraulic Analysis ................................................................................. 11-17
1105.5 Use of Nomographs .............................................................................................. 11-18 1105.5.1 Outlet Control ........................................................................................ 11-18 1105.5.2 Inlet Control........................................................................................... 11-18
1105.6 Design Criteria ..................................................................................................... 11-18 1105.6.1 Design Frequency.................................................................................. 11-18 1105.6.2 Maximum Allowable Headwater .............................................................. 11-18 1105.6.3 Method Used to Estimate Storm Discharge.............................................. 11-18 1105.6.4 Scale of Topographic Mapping Used to Delineate Contributing Drainage Areas........................................................................................................................... 11-18 1105.6.5 Manning’s Roughness Coefficient “n” ...................................................... 11-19 1105.6.6 Entrance Loss Coefficient “k e”................................................................. 11-19 1105.6.7 Minimum Cover ..................................................................................... 11-19 1105.6.8 Maximum Cover .................................................................................... 11-19 1105.6.9 Maximum Allowable Outlet Velocity......................................................... 11-19 1105.6.10 Headwall Type ..................................................................................... 11-19 1105.6.11 Contacts With County Engineer ............................................................ 11-19 1105.6.12 Minimum Pipe Size .............................................................................. 11-19 1105.6.13 Ordinary High Water Mark .................................................................... 11-19
1112 Notice of Intent (NOI) ......................................................................................................... 11-23 1112.1 General................................................................................................................ 11-23 1112.2 Routine Maintenance Project................................................................................. 11-24 1112.3 Watershed Specific NOI Requirements .................................................................. 11-24
1113 Erosion Control at Bridge Ends......................................................................................... 11-25 1113.1 General................................................................................................................ 11-25 1113.2 Corner Cone ........................................................................................................ 11-25
1114 Temporary Sediment and Erosion Control ........................................................................ 11-25 1114.1 General................................................................................................................ 11-25 1114.2 Cost Estimate for Temporary Sediment and Erosion Control ................................... 11-25
1115 Post Construction Storm Water Structural Best Management Practices........................... 11-25 1115.1 General................................................................................................................ 11-25 1115.2 Project Thresholds for Post-Construction BMP ....................................................... 11-25 1115.3 Water Quality and Water Quantity Treatment.......................................................... 11-26 1115.4 Water Quality Volume ........................................................................................... 11-27 1115.5 Water Quality Flow ............................................................................................... 11-27 1115.6 Redevelopment and New Construction .................................................................. 11-27
1115.6.1 Treatment Requirements for Redevelopment Projects .............................. 11-27 1115.6.2 Treatment Requirements for New Construction Projects ........................... 11-28
In order to properly design highway drainage facilities, it is essential that a reasonable estimate be made of the design and check discharges. Some of the more important factors affecting runoff are duration, intensity and frequency of rainfall; and the size, imperviousness, slope, and shape of the drainage area. Suitable topographic mapping shall be utilized to determine the contributing drainage area. For drainage areas over 100 acres, a 7.5 minute U.S. Geological Survey Quadrangle will ordinarily suffice. For smaller areas, or where discharges are calculated using the rational method, smaller scale maps (1”=50’ to 1”=800’) may be more appropriate. A proper evaluation should be made of the land use throughout the drainage area. Changes in land use within the drainage area which will occur in the immediate future shall be taken into account when determining design discharges. However, probable land use changes beyond this should not be assumed when determining design discharges. It is the responsibility of the local permitting/zoning agency to ensure proper land and water management techniques are utilized. These techniques will minimize the adverse affects of a change in land use. 1101.2 Procedures
1101.2.1 Statistical Methods
The statistical methods developed by the U.S. Geological Survey and published in USGS Reports 89-4126, 93-135 and 93-4080 shall be used to estimate runoff from larger drainage areas. A description and the limitations of these methods are described in Section 1003. 1101.2.2 Rational Method
The rational method is considered to be more reliable for estimating runoff from small drainage areas, less than the acreage for the USGS Regions; and for areas that contribute overland flow and shallow concentrated flow to the roadway ditch or pavement. The design discharge “Q” is obtained from the equation:
Q = CiA
where: Q = Discharge in cubic feet per second
C = Coefficient of runoff
I = Average rainfall intensity in inches per
hour, for a given storm frequency and for a duration equal to the time of concentration.
A = Drainage area in acres
The time of concentration is the time required for runoff to flow from the most remote point of the drainage area to the point of concentration. The point of concentration could be a culvert, catch basin or the checkpoint in a roadway ditch used to determine the need for velocity protection. Time of concentration is designated by “tc” and is the summation of the time of overland flow “to”, the time of shallow concentrated flow "ts" and the time of pipe or open channel flow “td”. Overland flow is that flow which is not carried in a discernible channel and maintains a uniform depth across the sloping surface. It is often referred to as sheet flow. The time of overland flow may be obtained from Figure 1101-1, a similar overland flow chart, or from the equation:
to ≈ 1.8(1.1-C) (L)(1/2)
(s)(1/3)
where: to = Time of overland flow in minutes
C = Coefficient of runoff
L = Distance to most remote location in
drainage area in feet
s = Overland slope (percent)
These methods should not be used to determine the time of travel for gutter, swale, or ditch flow. This equation and Figure 1101-1 assume a homogeneous drainage area. Where the overland flow area is composed of segments with
Drainage Design Procedures
11-2 April 2010
varying cover and/or slopes, the summation of the time of concentration for each segment will tend to over-estimate the overland flow time, “to”. In this case it may be more appropriate to use an average runoff coefficient "C" and an average ground slope in the Overland Flow Chart. Sheet flow is assumed to occur for no more than 300 feet after which water tends to concentrate in rills and then gullies of increasing proportion. This type of flow is classified as shallow concentrated flow. The velocity of shallow concentrated flow can be estimated using the following relationship:
V = 3.281ks0.5 where: V = Velocity in fps
k = Intercept coefficient
(see Table 1101-1)
s = Overland slope (percent)
Table 1101-1 Types of Surface
Intercept Coefficient “k”
Forest with heavy ground litter 0.076
Min. tillage cultivated; woodland 0.152
Short grass pasture 0.213
Cultivated straight row 0.274
Poor grass; untilled 0.305
Grassed waterways 0.457
Unpaved area; bare soil 0.491
Paved area 0.619 Shallow concentrated flow generally empties into pipe systems, drainage ditches, or natural channels. The velocity of flow in an open channel or pipe can be estimated using the Manning's equation. The travel time for both shallow concentrated flow and open channel or pipe flow is calculated as follows:
60VL
tort ds =
where:
ts = Travel time for shallow concentrated flow in minutes
td = Travel time for open channel or pipe flow in minutes
L = Flow length in feet
V = Velocity in fps
Where a contributing drainage area has its steepest slope and/or highest "C" value in the sub-area nearest the point of concentration, the rational method discharge for this sub-area may be greater than if the entire contributing drainage area is considered. The maximum runoff rate for a sub-area should be considered only if greater than that for the entire area. 1101.2.3 Coefficient of Runoff
The coefficient of runoff is a dimensionless decimal value that estimates the percentage of rainfall that becomes runoff. The recommended values for the coefficient of runoff for various contributing surfaces are shown in Table 1101-2. Where two values are shown, the higher value ordinarily applies to the steeper slopes. For Residential areas, lot size should also be considered in choosing the appropriate value for the coefficient of runoff. Generally, a higher value should be associated with smaller lots and a lower value should be associated with larger lot sizes. The selected coefficient should be based upon an estimation of the typical slope, lot size, and lot development. The total width contributing flow to a given point usually consists of surfaces having a variable land cover and thereby requires a weighted coefficient of runoff “C”. The weighted coefficient is obtained by averaging the coefficients for the different types of contributing surfaces, as noted in the following example:
The average rainfall intensity “i” in inches per hour may be obtained from the Intensity-Duration-Frequency curves shown on Figure 1101-2. Each set of curves applies to a specific geographic area, A, B, C, or D as shown on the Rainfall Intensity Zone Map, Figure 1101-3. The geographic areas were established from an analysis of rainfall records obtained from Weather Bureau stations in Ohio. Some political subdivisions may have developed curves for their specific area similar to Figure 1101-2. Such curves may be based on a much longer period of record and provide more reliable information. Any local curves proposed by the designer should be cleared with the Hydraulic Section, Office of Structural Engineering prior to incorporating that information in the drainage calculations.
1102 Open Water Carriers
1102.1 General
Open water carriers generally provide the most economical means for collecting and conveying surface water contributing to the roadway. The required capacity of a water carrier involves a determination of the velocity and depth of flow for a given discharge. These characteristics can best be obtained from charts that are based on Manning’s equation. Channel flow charts have been prepared for all the common water carrier shapes and are included in the Drainage Design Aids. A ditch computation sheet similar to that provided in the Appendix shall be used to perform or summarize ditch calculations. As a guideline, the desirable minimum roadway ditch grades should be 0.50% with a recommended absolute minimum of 0.25%. Lower grades may be used on large channels as necessary. Open water carriers should maintain a constant slope wherever possible. The proper location of a ditch outfall is quite important. Existing drainage patterns should be perpetuated insofar as practicable. Care should be taken to not capture an existing stream with the roadside ditch. If this is necessary, the designed ditch shall be in accordance to Section 1102.2.4. 1102.2 Types of Carriers
1102.2.1 Standard Roadway (Roadside) Ditches
The various roadside ditches shown in Volume I, Roadway Design, have proven to be safe and to provide adequate flow capacity. A ditch is considered to be standard when the centerline is parallel to the edge of the pavement and the flowline is a uniform distance below the edge of pavement. A modification of the above is required when the grade of the pavement is too flat to provide acceptable ditch flow, thereby creating the need for a special ditch. Channel charts, Drainage Design Aid Figures 1100-1 through 1100-10, are included for use in determining velocity and depth of flow for standard ditches having variable side slopes. 1102.2.2 Special Ditches
Special ditches other than the modified standard roadway ditch described in Section 1102.2.1 above, include the following:
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11-4 April 2010
A. The steep ditch beyond the toe of the embankment used to carry the flow from a cut section to the valley floor.
B. Toe of fill ditch which is separated from the
toe of fill by a minimum 10 foot wide bench, having a minimum transverse slope of ½ inch per foot toward the ditch.
C. Deep parallel side ditches separated from the
pavement by a wide bench or earth barrier. The special ditches described in A, B and C above are ordinarily trapezoidal in shape and appropriate charts for the hydraulic analysis are included in this section of the manual or in the FHWA publication “Design Charts for Open Channel Flow”’ Hydraulic Design Series No. 3. It is required that the calculated flowline elevation be shown on each special ditch cross section. 1102.2.3 Median Ditches
The median ditches that are an integral part of all earth medians have the same shape and capacity features as the standard roadside radius ditch and the appropriate ditch chart is applicable for the hydraulic analysis. The fully depressed earth median provides adequate hydraulic capacity and the appropriate flow charts in the Drainage Design Aid Figures 1100-11, 1100-12 and 1100-13 have been developed for that shape. The rounding shown on the charts varies from 8 feet to 4 feet, depending on the width of the median. The slight discrepancy in the rounding from that shown in Volume I, Roadway Design, is not considered to affect the accuracy of the charts. 1102.2.4 Channel Relocations
Major channel relocations should be avoided. However, if it becomes necessary to relocate a channel adhere to the following: The design year frequency used for channel relocations shall be that given in Section 1004.2. All channel relocations shall carefully be designed to preclude erosion or unreasonable changes in the environment. Whenever possible, channel relocations shall be restricted to the downstream end of proposed culverts. The relocated channel shall be of a similar cross-section. Where the existing channel exhibits a two-stage cross section morphology, it shall be replaced with like kind. The two-stage channel is comprised of two distinct areas. The first of these
is a meandering bankfull width that carries the channel-forming discharge. The second area is the flood plain width. See Figure 1102-2 for a graphical representation of the major channel features. The proposed channel should be designed such that it matches the existing channel as closely as possible in regards to existing geomorphic conditions (e.g., channel slope and length, velocity, depth of flow, cross-sectional geometry, channel sinuosity, energy dissipation, etc.). The existing channel geometry and physical characteristics should be established from reference reaches and idealized geometry. The reference reaches should be selected from stable channel reaches close to the relocated section or in locations with similar watershed and valley conditions. The relocated channel should be designed to duplicate the existing hydraulic properties for the bankfull design frequency. The flood clearance criteria given in Section 1005 should also be met. Additional information on the design of relocated channels can be found in the United States Department of Agriculture publication, “Stream Corridor Restoration: Principles, Practices and Processes”. The principals given in this publication utilize idealized channel geometry. The actual design should be refined using the channel geometry and physical characteristics of reference reaches. 1102.2.5 Channel Linings and Bank Stabilization
The use of soil bioengineering should be used to stabilize banks for relocated or impacted channels when practicable. Native plant species should be used when feasible. Bank stabilization using bioengineering is covered in the previously referenced USDA publication as well as the AASHTO Model Drainage Manual and the USDA Engineering Field Handbook, chapter 16, part 650. The design procedures and methods for determining the effectiveness of the traditional channel linings are covered in the Federal Highway Administration Hydraulic Engineering Circular No. 15 “Design of Stable Channels With Flexible Linings”.
Determine the depth of flow using a 10-year frequency storm, and determine the shear stress and width of the ditch lining (if required) using a 5-year frequency storm. Where a flexible ditch lining is required for calculated stresses exceeding the allowable for seed, the minimum width of the lining shall be 7.5 feet. Additional required width is in increments of 3.5 feet. The installed width of all ditch linings is centered on the flow line of the ditch. The depth of flow shall be limited to an elevation 1 foot below the edge of pavement for the design discharge. The depth of flow in toe of slope ditches shall be further limited such that the design year discharge does not overtop the ditch bank. 1102.3.2 Ditch Protection
The shear stress for the five-year frequency storm shall not exceed the values shown in Table 1102-1 for the various flexible linings. Table 1102-1
Allowable Shear Stress
Permanent Protection
Protective Lining Allowable Shear Stress (psf)
Seed (659) 0.40
Sodding, Ditch Protection (660)
1.0
Temporary Protection
Ditch Erosion Protection Mat Type___ (670)
A 1.25
B 1.50
C 2.0
E 2.25 F 0.45 G 1.75
The temporary linings will reach a value of 1.0 psf upon vegetation establishment. Use the temporary lining shear stress values in Table 1102-1 on a temporary basis only (6 months or less).
Calculate the actual shear stress by the following equation:
D= Water surface depth ft
S = Channel slope ft/ft τac = Actual shear stress lbs/ft
2
If the calculated shear stress exceeds that shown in table 1102-1 then use the following permanent shear stress values within the stated limitations: A. Seeding and Erosion Control with Turf
Reinforcing Mat (Supplemental Specification 836) where the ditch slope is less than 10% and maximum shear stress are as follows:
Turf Reinforcing Mat
Type Maximum Shear
Stress (psf) Type 1 2.00 Type 2 3.00 Type 3 5.00
B. Type B, C or D Rock Channel Protection may
be used to line the ditch if the nearest point of the lining is outside the design clear zone or located behind guardrail or barrier. The actual shear stress is based upon the parameters of the channel slope and depth of flow for the 5-year discharge. The shear equation if valid for discharges less than 50 cfs with slopes less than 10% when evaluating Rock Channel Protection.
Allowable Shear Stress
RCP Type τa lbs/ft2
B 6 C 4 D 2
C. Type B or C RCP may be utilized for lining
ditches on steep grades (slopes from 10%- 25%) that carry flow from the end of a cut section down to the valley floor. Use HEC-15 procedures with a safety factor of 1.5 for steep gradient channels (refer to HEC-15). Contact the Office of Structural Engineering, Hydraulics Section for further guidance of RCP usage for 5-year discharges greater than or equal to 50 cfs.
D. Tied concrete block mat protection (601) may
be used for channels with 2:1 or flatter side slopes with profile grades at 25% or less.
τ ac= 62.4 D. S.
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The matting may be used within the clear zone provided that the top of the blocks are flush with the finished grade. Backfill and anchor the block mat per the manufacturers recommendations. The allowable shear stress for each type is shown in table 1102-2.
Table 1102-2
CONCRETE BLOCK MAT SHEAR STRESS
Type
Allowable Shear
Stress (psf)
1
3
2
5
3
7
E. A concrete lining should be considered only
as a last resort. Contact the Hydraulics Section, Office of Structural Engineering, before using a concrete lining.
1102.3.3 Roughness
Suggested values for Manning’s Roughness Coefficient “n” for the various types of open water carriers are listed in Table 1102-3. Table 1102-3 Type of Lining
The Standard No. 4, 5, and 8 Catch Basins are suitable for the standard roadside designs covered in Volume I, Roadway Design. The tilt built into the basin top provides a self-cleaning feature when the basins are used on continuous grades and the wide bar spacing minimizes clogging possibilities, thereby resulting in an efficient design. The bases of the 4, 5 and 8
Catch Basins can be expanded to accommodate larger diameter conduits by specifying Standard Construction Drawing CB-3.4. The bar spacing can be decreased, when desirable for safety reasons, by specifying Grate “E” for the No. 4 and Grate “B” for the No. 5. Provide 150 feet of ditch erosion protection upstream of all No. 4, 5 and 8 Catch Basins, regardless of velocity. The following catch basin types are generally recommended based on the size and shape of the ditch. A. Standard No. 4 for depressed medians wider
than 40 feet. B. Standard No. 5 for 40 foot radius roadside or
median ditches. (Use Grate “B” where pedestrian traffic may be expected.)
C. Standard No. 8 for 20 foot radius roadside or
depressed medians 40 feet or less in width. D. Standard No. 2-2-A may be used in
trapezoidal toe ditches where the basin is located in a rural area. The basin should also be located outside the design clear zone or behind guardrail where the protruding feature of the basin is not objectionable. The capacity of the side inlet catch basin window, for unsubmerged conditions, may be determined by the standard weir equation:
Q=CLH3/2
where C is a weir coefficient, generally 3.0, L is the length of opening in feet, H is the distance from the bottom of the window to the surface of the design flow in feet. The catch basin grate is considered as an access point for the storm sewer and its capacity to admit flow is ignored for continuous grades.
E. Standard No. 2-2-B should be used where
minor, non-clogging flows are involved such as yard sections and the small triangular area created by the guardrail treatment for a depressed median at bridge terminals. Standard No. 2-3 through No. 2-6 catch basins should be provided where a larger base is required to accommodate pipes larger than 21 inches in span or sewer junctions, or where a No. 2-2-B catch basin will not provide adequate access to the sewer.
F. In urban areas, Standard Side Ditch Inlets
should be used to drain small areas of trapped water behind curbs and/or between driveways.
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1102.3.5 Calculated Catch Basin Spacing
Catch basins must be provided to intercept flow from open water carriers when the depth of flow or velocity exceeds the maximum allowable for the design storm for all highway classifications. The standard ditch catch basins, designated Catch Basin No. 4, Catch Basin No. 5, and Catch Basin No. 8, include an earth dike. The dike is approximately 12 inches above the flowline of the grate, immediately downstream from the catch basin and serves to block the flow on continuous grades and create a sump condition. When the calculated depth of flow or velocity exceeds the maximum allowable at the checkpoint in the ditch, a catch basin or ditch lining will be required. However, the capacity of the catch basin may be less than the capacity of the ditch and thereby control the catch basin spacing. Figure 1102-1 may be used to check the capacity of a catch basin grate in a sump. To use Figure 1102-1, the calculat ed discharge at the ditch checkpoint shall be doubled to compensate for possible partial clogging of the grate. In cut sections, the accumulated ditch flow shall be carried as far as the capacity, allowable depth, or velocity of flow will permit. The first catch basin in the roadside or median ditch will determine the need for a storm sewer system required for the remainder of the cut. Velocity control should be extended as far as inexpensive flexible ditch linings will permit. Consideration should also be given to providing positive outlets for underdrains and providing access to longitudinal sewer systems when locating ditch catch basins. 1102.3.6 Arbitrary Maximum Catch Basin Spacing
Catch basins are required at the low point of all sags and the earth dike noted in Section 1102.3.5 shall be omitted. The maximum distance between catch basins in depressed medians in fill sections shall be as shown in Table 1102-4. Where underdrains are utilized, catch basins shall be provi ded at a maximum spacing of 1000 feet [300 meters] (500 feet [150 meters] with free draining base) to provide a positive outlet for underdrains.
Table 1102-4 Depressed Median Catch Basin Spacing
(Fill Sections) Median Width
Desirable Spacing
Maximum Spacing
84 feet 1250 feet 1500 feet
60 feet 1000 feet 1250 feet
40 feet 800 feet 1000 feet
1102.4 Ditch Design Criteria - Design Traffic of 2000 ADT or Less
1102.4.1 Design Frequency
A 5-year frequency storm shall be used to determine the depth of flow, and a 2-year frequency to determine the shear stress of flow and width of ditch lining, where needed. The depth of flow shall be limited to an elevation 9 inches below the edge of pavement for the design discharge. The depth of flow in toe of slope ditches shall be further limited such that the design year discharge does not overtop the ditch bank. The minimum width of lining shall be in accordance with Section 1102.3.1. 1102.4.2 Shear Stress Protection
Shear stress protection shall be in accordance with 1102.3.2 except that a 2-year frequency event shall be used. 1102.4.3 Roughness
The roughness used for the hydraulic analysis shall be based on the Manning's Roughness Coefficient values shown in Table 1102-3. 1102.4.4 Catch Basin Types
Standard No. 5 Catch Basins, No. 2-2-A Catch Basin (within their safety limitations as discussed in Section 1102.3.4(D)) and No. 2-2-B Catch Basins should be considered for the lower ADT highways. Standard No. 4 Catch Basins should be used where additional capacity is required.
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1102.5 Design Aids for Ditch Flow Analysis
1102.5.1 Earth Channel Charts
Standard radius roadside ditch charts have been prepared, based on the Manning’s equation, to facilitate the hydraulic analysis of ditch flow and are included in the Drainage Design Aids. Some of the more commonly used trapezoidal channel charts are also included. Other trapezoidal channel charts (with 2:1 - 2:1 side slopes and bottom widths varying from 2 feet to 20 feet are available in the Federal Highway Administration publication referenced in section 1102.2.2. All earth channel charts have been prepared using a Manning's Coefficient of Roughness of 0.03, which is recommended for a seed lining (Construction and Material Specifications Item 659). Qn and Vn scales have been included on all channel charts so that the channel flow may be analyzed for any value of “n” depending on the roughness of the channel or lining. 1102.5.2 Rectangular Channel Charts
Vertical side channel charts that can be used to analyze the open channel flow in box culverts are included in the Federal Highway Administration publication “Design Charts for Open Channel flow,” previously referred to.
1103 Pavement Drainage
1103.1 General
When curbs are provided at the edge of pavement or paved shoulder, (primarily in urban areas), it is necessary to determine the proper type of pavement inlet (or catch basin) to control the spread of water and depth of flow on the pavement. Present day geometric design has resulted in relatively flat transverse and longitudinal pavement slopes. These slopes require more pavement inlets (or catch basins) and consequently result in an appreciable increase in the drainage cost. To alleviate the above, where curb is permissible, standard curb and gutter should be used adjacent to the pavement. Where standard curb and gutter cannot be provided, the outside lanes of a muli-lane pavement should maintain a transverse slope of 1/4 inch per foot (0.02). If paved shoulders are provided, the drainage cost will be decreased appreciably due to the
large volume of flow that can be carried on the pavement shoulder without exceeding the allowable depth of 1 inch below the top of curb or a maximum of 5 inches; a maximum depth of 6 inches is permissible where a barrier shape is provided adjacent to the pavement. Furnish a drainage design that will reduce the need for bridge scuppers by intercepting the flow prior to the bridge. A pavement drainage computation sheet similar to that provided in the Appendix shall be used to perform or summarize necessary computations. Additional information concerning pavement drainage can be obtained from the Federal Highway Administration Hydraulic Engineering Circular No. 22, "Urban Drainage Design Manual." 1103.2 Design Frequency
Pavement inlets (or catch basins) shall be spaced to limit the spread of flow on the traveled lane (considered to be 12 feet wide) as shown in Table 1103-1. The allowable spread may be increased slightly for streets carrying predominantly local traffic and with design speeds less than 45 mph. Design shall be based upon the following frequencies: Freeways . . . . . . . . . . . . . . . . . . . . . . . 10 Years High volume highways (over 6000 ADT Rural or 9000 ADT Urban) . . . 5 Years
All other highways . . . . . . . . . . . . . . . . 2 Years For underpasses or other depressed roadways where ponded water can be removed only through the storm sewer system, the spread shall be checked for a 50-year storm for Freeways and high volume highways as defined above, and for a 25-year storm for other multiple lane highways. Typically, this criteria does not apply to 2-lane facilities. Call the Hydraulics Section, Office of Structural Engineering if encountered. The ponding will be permitted to cover all but one through lane of a multiple lane pavement. The depth of flow at the curb shall not exceed 1 inch below the top of the curb for the design discharge regardless of the type of highway. A maximum depth of 6 inches is permissible where a barrier shape is provided adjacent to the pavement.
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Table 1103-1
Allowable Pavement Spread* Freeways 0 feet
High Volume Highways (Over 6000 ADT rural or 9000 ADT urban)
$45 mph 4 feet
< 45mph 2 lanes 6 feet $4 lanes 8 feet All other Highways 2 lanes 6 feet
$4 lanes 8 feet
*Pavement spread applies to the through lane only.
1103.3 Estimating Design Discharge
Runoff contributing to curbed pavements shall be estimated by the rational method, as explained in Sections 1101.2.2, 1101.2.3 and 1101.2.4. The time of concentration “tc” shall be the actual time of concentration calculated according to Section 1101.2.2 with an absolute minimum time of 10 minutes. In urban areas, where justifiable (e.g. contributing drainage area would be difficult to determine), the “strip method” may be used to determine contributing drainage areas. The strip method assumes a contributing drainage area of 150 feet taken on each side of the roadway centerline. 1103.4 Capacity of Pavement Gutters
A pavement gutter has a right triangular shape, with the curb forming the vertical leg and the straight pavement slope, the gutter plate of a curb and gutter, or a paved shoulder forming the hypotenuse. A standard curb and gutter adjacent to a straight pavement slope, or paved shoulder, forms a composite gutter section which complicates the flow analysis. In most cases, the top width of the water surface in a pavement gutter far exceeds the height of the curb. The hydraulic radius does not accurately describe the gutter cross section in this situation, thereby requiring a modification to the Manning’s equation to analyze the gutter flow. The accepted modification results in the following equation:
Q = 0.56 Z S1/2 d8/3
n
where: Q = Discharge in cubic feet per second
Z = Reciprocal of the pavement cross
slope
n = Manning’s Coefficient of Roughness (Table 1102-3)
s = Longitudinal pavement slope
d = Depth of flow in gutter section at curb in feet
Figure 1103-1 provides a graphical solution for the above equation and its use is comparatively simple for straight transverse pavement slopes. However, the use of the nomograph to determine depth of flow at the curb and resulting spread on the pavement for composite sections is much more involved. 1103.5 Pavement Flow Charts
Charts have been prepared for the more commonly used curbed pavement typical sections, and they are included in the Drainage Design Aids. The charts are particularly helpful for determining the flow for composite pavement sections where the spread can be read directly from the appropriate Pavement Flow Chart. To use the charts, enter with a predetermined design discharge (total flow) Qt in the gutter in cubic feet per second and proceed vertically to intersect the longitudinal gutter slope line. At that intersection, read the spread in feet shown on the diagonal spread lines. The spread of flow will generally control the pavement inlet or catch basin spacing, where the transverse and longitudinal slope of the pavement is relatively flat. The above is prevalent in long flat sag vertical curves, where a flanking inlet (or catch basin) should arbitrarily be provided on both sides of the low point in a pavement sag. This is particularly so for Freeways. Three inlets or catch basins in a sag can be justified only on the basis of need for other highway classifications. Usually a Standard 6 foot pavement inlet or No. 3A catch basin will be adequate, and they should be placed where the grade elevation is approximately 0.20 feet higher
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than at the low point. Furnish a CB -No. 3 at the sump. Inlets or catch basins should arbitrarily be placed upstream of all intersections, bridges and pedestrian ramps. When justified, inlets (or catch basins) should be located a minimum of 10 feet off drive aprons, intersection return radii, pedestrian ramps or curb termini. 1103.6 Bypass Charts for Continuous Pavement Grades
Bypass charts are included for the standard pavement inlets and catch basins in the Drainage Design Aids. Bypass for a given structure can be read directly from the chart (At the intersection of the spread, determined in Section 1103.5, and the longitudinal gutter slope, read the bypass flow Qb on the abscissa). Experience has proven that, for greater efficiency, inlets should be sized to bypass a minimum of 10% to 15% of the design discharge. This criterion should be used to determine the type or length of inlet to be used in a given location. It is not intended to establish the required spacing. The most efficient design maintains the allowable spread on continuous grades and at the sag. The bypass for a catch basin or inlet should be added to the total flow in the adjacent downstream gutter section. 1103.6.1 Curb Opening Inlets
The flow bypassing a standard curb opening inlet, for pavement transverse slopes or combination of slopes differing from the charts included in the Drainage Design Aids, may be obtained from Figure 1103-2. The use of curb opening inlets should be avoided where bicycle traffic is expected. 1103.6.2 Grate or Combination Grate and Curb Opening Inlet
The standard pavement catch basin in this category is considered to intercept all the flow over the grate when used on continuous grades. A portion of the flow outside of the edge of the grate will also be intercepted, the amount varying with the depth of flow “y” along the edge of the grate. The depth “y” can be determined from Figure 1103-1, and the resulting flow spilling over the edge of the grate from Figure 1103-2, using a ½ inch local depression for straight transverse pavement slopes, or no local depression for a composite gutter section. The curb opening of a combination catch basin on a continuous grade
will admit some flow, particularly if there is a partial clogging of the grate; however, the additional capacity should be considered as a factor of safety only. 1103.7 Grate Catch Basins and Curb Opening Inlets In Pavement Sags
The spread determined from the pavement flow charts need not be checked any closer than 25 to 50 feet on either side of the sag, well beyond the limits of the local depression. The spread in the sag should be determined from the depth of flow at the edge of grate using Figure 1103-3 and should include the total flow (contributions from each side of the sag vertical curve) reaching the inlet or catch basin. Standard No. 3 catch basins should be used in pavement sags. The capacity of the grates to admit flow is based on the depth of ponding around the grates. The capacity of the grates shown in Figure 1103-3 is based on weir flow over the edge of the grate, up to a depth of 0.4 feet. For greater depths, the total area of grate opening is considered, with no deduction made for possible clogging. When evaluating the spread in a depressed sag for a 25-year or 50-year event, the capacity of the window shall be considered. This capacity may be obtained from Figure 1103-4. The curb opening capacity should be added to the grate capacity for submerged conditions. Where the low point of a sag vertical curve occurs in a drive, a No. 6 catch basin should be provided at the low point with flanking No. 3A catch basins as per Section 1103.5. No. 6 catch basins may be used along curbed roadways and medians provided that the grate capacity is not exceeded.
1104 Storm Sewers
1104.1 General
Storm sewer systems are designed to collect and carry storm water runoff from the first pavement or ditch inlet, or catch basin to the predetermined outlet. (Further reference to inlets infers either inlets or catch basins). Long cut sections often result in the need for longitudinal trunk sewers to accept the flow from a series of inlets. Th e proper location of a sewer outlet is quite important. Existing drainage patterns should be perpetuated insofar as practicable. Careful consideration should be given to the possibility of actionable damage for the diversion of substantial volumes of flow. Long fill sections requiring
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median or pavement drains may best be served by transverse sewers that outlet independently at the toe of fill ditch. Storm sewer systems shall be sized to convey the current flow from areas naturally contributing to the highway or from intercepting existing storm sewers. Storm sewer systems may be oversized at the request of a local government entity to convey flow from areas beyond those considered highway responsibility or increased flows from anticipated development with the approval of the Hydraulic Section, Office of Structural Engineering. The additional cost to construct the increased sized storm sewer system will be the responsibility of the local government. The proration of project funds and local government funds will be determined from estimated construction costs. The project funding participation will be determined as a percentage of the total cost of the affected plan items. The percentage will be computed by dividing the estimated cost to construct a highway responsibility system only by the estimated cost to construct the oversized system. The affected plan items and participation percentage will be noted in the plan general summary. Type B conduit shall be specified for storm sewers under pavement, paved shoulders and commercial or industrial drives and Type C conduits for storm sewers beyond those limits. However, the type of conduit shall not be changed for a short run of conduit which would ordinarily require a change in conduit type. As an example of the above, Type B should be used for a transverse conduit that is required to drain an earth median catch basin in an embankment section under the pavement to a point approximately 10 feet from the embankment slope. A concrete collar, as per Standard Construction Drawing DM -1.1, should be provided to connect the Type B and a Type F Conduit, located back of, and parallel to, the embankment slope. Type F conduit, 707.05 Type C or 707.21 shall be provided for the pipe specials required to negotiate the bend at the top and bottom of the embankment. A detail is provided in figure 1104-1. The Construction and Material Specifications stipulate the permissible pipe shapes and materials. Storm sewer designs will be based on round pipe, and the choice of the permissible material types for the conduit specified will be the contractor’s option. Extensions of existing pipes should typically be made using like kind material.
The length of conduit to be paid for will be the actual number of linear feet, measured from center-to-center of appurtenant small structures. No deduction will be made for catch basins, inlets or manholes that are 6 feet or less across, measured in the direction of flow. Conduits placed on slopes steeper than 3:1 or with beveled or skewed ends are measured along the invert. 1104.2 Design Considerations
1104.2.1 Storm Sewer Depth
Keep a storm sewer system as shallow as possible, consistent with the following controls: A. Provide a minimum cover of 9 inches from
the top of a rigid pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the rigid pipe to the pavement surface be less than 15 inches. Provide a minimum cover of at least 18 inches for pipe not under pavement.
B. Provide a minimum cover of 12” from the top
of flexible pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the flexible pipe to the pavement or ground surface be less than 24”.
C. Provide a minimum cover of 4” from the top of
extra strength pipe to the bottom of the pavement subbase; however, in no installation shall the distance from the top of the extra strength pipe to the pavement surface be less than 10 inches. Provide a minimum cover of at least 4” if not under the pavement. Check with the Hydraulic section to determine the required extra strength. If 10 inches of minimum cover is not achievable, the pipe is required to be special designed and shown as per plan.
D. Provide a sufficient depth to permit the use of
precast inlets, catch basins and manholes. Refer to the Standard Construction Drawings for this information. In no installation shall the top of pipe be in the precast top section of the inlet, catch basin or manhole. See Table 1104-1 for rigid pipe thicknesses.
E. Provide a sufficient depth to avoid
interference with existing utilities such as sanitary sewers, the grade of which cannot be changed.
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F. Provide a sufficient depth to create a positive outlet for underdrains. It is desirable to maintain the underdrain outlet 12 inches above the flow line of the outlet structure with 6 inches as a minimum.
G. Provide sufficient slope to maintain a
minimum velocity of 3 feet per second, for self-cleansing. This velocity is calculated using the “just full” Manning’s Equation.
H. Match the crown of a smaller upstream pipe
in a longitudinal trunk sewer to the crown of the adjacent downstream pipe.
Where proposed highway storm sewers or ditches will interfere with existing private drains carrying treated or untreated sanitary flow, submit the names and addresses of the affected property owners to the District Deputy Director. Obtain the above information well in advance of the Field Drainage Review so the appropriate provisions of Directive No. 22-A can be followed. 1104.2.2 Storm Sewer Access
Most standard catch basins and pavement inlets will provide sufficient access to small shallow sewers. Catch basin or pavement inlets can be used to negotiate changes in sewer sizes or
minor horizontal or vertical direction changes within the size limitation of the structure, but more pronounced changes may require manholes. It may be necessary, or desirable to locate longitudinal trunk sewers away from the curb to provide for a utility strip between the curb and the sidewalk and to avoid a conflict with the underdrain system. This will require properly spaced manholes in the sewer line. Small sewers (under 36 inches in diameter) located under or near the edge of pavement, should be accessible at intervals not to exceed 300 feet. For sewers sized 36 to 60 inches manholes should be spaced every 500 feet maximum. Manholes should be provided every 750 to 1000 feet maximum for larger sewers. 1104.2.3 Rock Excavation for Storm Sewer
If it is known that bedrock will be encountered in the excavation for storm sewer installation, relocate the storm sewer. If bedrock cannot be avoided, separate the quantities of the storm sewer in rock and include “603, As Per Plan” in the plans. 1104.3 Layout Procedure
1104.3.1 Plan
A print of the plan sheets involved should be used to spot catch basins and inlets that are required to drain the project and satisfy maximum allowable depth and/or spread of flow. A strip map showing the delineated drainage area and topography is required. The map will provide the designer with a means of determining the drainage area and the weighted coefficient of runoff for the individual areas contributing flow to the required storm sewer system. 1104.3.2 Profile
A profile of the existing and proposed pavement or ground line over the proposed sewer location should be plotted. On the same profile, plot the locations of catch basins, inlets and manholes, along with a tentative storm sewer system. 1104.4 Storm Sewer Design Criteria
1104.4.1 Design Frequency
All storm sewers shall be sized to flow just full (i.e. depth of flow for maximum discharge) for a 10-year frequency storm. The size is determined by working downstream from the first sewer run. It will be acceptable to use a discharge of a more
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frequent occurrence if consistent with local policy (depending upon the design ADT of the roadway) or to avoid extensive replacement of an existing downstream drainage system. 1104.4.2 Hydraulic Grade Line
Starting at the storm sewer system outlet and working upstream, the elevation of the hydraulic grade line at the upper end of each sewer run should be determined using a 25-year frequency. It will be acceptable to use a discharge of a more frequent occurrence if consistent with local policy (depending upon the design ADT of the roadway) or to avoid extensive replacement of an existing downstream drainage system. Ordinarily, the hydraulic grade line will be above the top of the pipe, causing the system to operate under pressure. If, however, any run in the system does not flow full, (pipe slope steeper than the friction slope) the hydraulic grade line will follow the friction slope until it reaches the normal depth of flow in the steep run. From that point, the hydraulic grade line will coincide with the normal depth of flow until it reaches a run flatter than the friction slope for that run. The starting elevation for the hydraulic grade line determination should be the higher of either: the downstream tail water channel water surface elevation or (dc+D)/2 at the system outlet. Section 1105.6.1 The intensity “i” in the rational equation Q=CiA [Q=CiA/360] used to determine the check discharge (25-year frequency) shall be the same for all sewer runs as that calculated for the last, or downstream run, in a continuous sewer system. The hydraulic grade line shall not exceed the following for any roadway with greater than 2000 ADT: A. 12 inches below the edge of pavement for
sections without curb. B. The elevation of a curb opening inlet or grate
elevation of a pavement catch basin. Consideration shall be given to a reduction in the design frequency and to more liberal hydraulic grade line controls for less important highways than those noted above. The check discharge, to determine the elevation of the hydraulic grade line for highways having depressed sags that must be drained by storm sewers, shall be based on a 50-year frequency. One directional lane of a multiple lane highway or
one-half of a lane on a 2-lane highway should be passable when the sewer system is discharging the 50-year storm. Storm sewers for all highways shall satisfy a 50-year check to preclude flooding of buildings or extensive flooding of private property. If the hydraulic grade line exceeds the limits noted above, the controlling sewer size shall be increased. (These criteria are not intended to lower existing high water elevations) 1104.4.3 Coefficient of Runoff
The weighted coefficient of runoff shall be determined as explained in Section 1101.2.3 1104.4.4 Time of Concentration
The time shall be determined as explained in Section 1101.2.2. A minimum time of concentration of 15 minutes to the first ditch catch basin and 10 minutes to the first pavement inlet shall be used. The actual calculated time of concentration shall be used when values greater than these minimums occur. 1104.4.5 Pipe Roughness Coefficient
A Manning’s “n” of 0.015 shall be used for sewers 60 inches in diameter and under, and 0.013 for larger sewers. The basic “n” value for smooth pipe, concrete, vitrified clay, bituminous lined corrugated steel or thermoplastic is 0.012. The increased values are recommended for sewers to compensate for minor head losses incurred at catch basins, inlets and manholes located in a storm sewer system. 1104.4.6 Minimum Storm Sewer Pipe Size
A minimum pipe diameter of 15 inches shall be used for Freeways and Freeway ramps (Where an existing storm sewer is to remain in service, it is not necessary to replace, hydraulically adequate pipes to meet this criterion) and 12 inches for other highways. 1104.5 Hydraulic Design Procedure
With the layout suggested in Section 1104.3, start with the upper catch basin or inlet and determine the value of CA for the contributing flow (CA is the product of the weighted coefficient of runoff and the drainage area). Next, determine the time of concentration for the first area and the corresponding rainfall intensity “i” from the proper curve shown on Figure 1101-2. The design
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discharge “Q” to use to determine the required size of the first sewer from MH No. 1 to MH No. 2 is the product of Ca x i [0.0028CA x i]. At manhole No. 2, determine the value of CA for the additional area contributing at that point and add to the CA for MH No. 1. Compute the time of flow in the storm sewer from MH No.1 to MH No. 2 in minutes and add to the time of concentration at MH No. 1. Check the time of concentration for the area contributing to MH No. 2, and use the larger of the two as the duration for the new value of rainfall intensity for computing the design flow from MH No. 2 to MH No. 3. It is obvious that the process is quite involved, and a storm sewer computation sheet similar to that provided in the Appendix shall be used to tabulate the required information. The calculations for lateral connections to the longitudinal trunk sewer should be tabulated separately from the trunk sewer calculations.
1105 Roadway Culverts
1105.1 General
A culvert generally carries a natural stream under the highway embankment. The culvert horizontal and vertical alignment should approximate that of the natural channel and thereby minimize stream impacts and the need for channel relocations. Ensure the upstream invert is not below the natural channel unless the culvert has depressed inverts, a paved depressed approach apron, or an improved inlet. Optimum culvert design (i.e., best hydraulic performance and least environmental impacts) occurs when the roadway alignment is normal to the flow in the channel and is located on a relatively straight and stable section of the channel. Roadway alignment needs to be considered early in the design process to provide optimum culvert design. The proposed roadway should avoid stream confluences. Culverts should not be placed on skews in excess of 45º or as further limited in Section 1008. A single-cell round pipe should be the designer’s first choice. In cases where required cover or discharge precludes a round pipe, consideration should be given to a single-cell elliptical concrete, metal pipe-arch, prefabricated box culvert or three-sided structure, in order of preferred use. For justification of multiple cell culverts, see Section 1105.7.2.
Culvert location should perpetuate existing drainage patterns (depth of flow, direction of flow, overbank flow) to the maximum extent practicable. Diversion of substantial volumes of flow requires regulatory consideration and possible actionable damage. Label the depth of the Ordinary High Water Mark (OHWM) for jurisdictional waterways on the plans for all culverts. The depth is measured from the centerline of the waterway. The OHWM is calculated per Section1105.6.13 or determined by the Office of Environmental Services. 1105.2 Stream Protection
Stream protection practices are provided to improve stream channel stability. Erosion of the stream channel can migrate upstream and downstream without proper protection at the structure. Provide stream protection practices (water quantity treatment) for all culvert projects when the project earth disturbing acreage exceeds the thresholds for post-construction Best Management Practices (BMP) outlined in Section 1115.2. Exceptions for providing stream protection to meet post-construction BMP requirements are noted in Section 1115.3. In addition to post-construction BMP requirements, waterway permit conditions and site specific features may require the use of practices described throughout this Section. Stream protection for culvert projects is provided through the use of the following practices:
For existing culvert replacements, inspect the channel for erosion that has caused undercutting or downcutting at the inlet of the culvert. At locations with evidence of undercutting or downcutting, provide a concrete apron according to Section 1106.3 at the inlet and outlet of the culvert to restore previous stream elevations and provide stream protection. The use of each stream protection practice is limited based on project specific conditions. If the stream protection practices listed above are not applicable or available based on project type,
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site constraints or limitations, the project is not exempt from providing stream protection BMP. In addition to the stream protection practices described within this Section, the following post-construction storm water BMP may be utilized within available right-of-way or right-of-way being obtained for roadway purposes to provide stream protection and treat storm water runoff when the project earth disturbed area is equal to or exceeds one acre:
• Exfiltration Trenches (See Section 1117.1)
• Extended Detention (See Section 1117.4) • Retention Basin (See Section 1117.5) • Bioretention Cell (See Section 1117.6) • Infiltration Methods (See Section 1117.7) • Constructed Wetlands (See Section
1117.8) See Sections 1115 through 1117 for further information concerning post-construction storm water BMPs. 1105.2.1 Bankfull Discharge Design
Culverts utilizing Bankfull Discharge Design are required to convey the bankfull discharge with minimum change in the stream energy for the adjoining channel sections when compared to the existing conditions. The proposed culvert will minimize the impact to the stream channel by closely matching the existing depth of flow with the proposed depth of flow for the bankfull discharge. Provide Bankfull Discharge Design for all culverts conveying streams with the following exceptions:
• The culvert is a replacement structure (permitted under a Nationwide Permit #3 - Maintenance).
• The culvert rise is 30" or less.
• The culvert is located on bedrock.
• The culvert slope exceeds 3%.
If multiple cell culverts are provided, ensure only one culvert conveys the bankfull discharge. Place the invert of additional culverts at the water surface elevation generated by the bankfull discharge.
Use the following design steps when performing a bankfull discharge design:
1. Determine the bankfull discharge using USGS report 2005-5153, “Bankfull Characteristics of Ohio Streams and Their Relation To Peak Streamflows”. Use the regression equation that utilizes USGS map-based explanatory variables. The report can be obtained from USGS at: http://pubs.usgs.gov/sir/2005/5153/.
2. Determine the culvert size from traditional
culvert hydraulic design. 3. Depress the culvert invert according to
Section 1105.2.2. 4. Determine the depth of flow for the pre-
developed channel using the bankfull discharge at locations 25 feet before the culvert inlet, at the culvert, and 25 feet beyond the culvert outlet. Determine the depth of flow for the bankfull discharge based on field-obtained stream cross-sections and the use of a standard step-backwater water-surface profile model such as HEC-RAS or the use of other software capable of calculating depth of flow based on Manning’s equation.
5. Determine the depth of flow for the post-
developed channel using the bankfull discharge at the same locations identified in Step 4 through use of a standard step-backwater water-surface profile model such as HEC-RAS or the use of other software capable of calculating depth of flow based on Manning’s equation. The cross section at the culvert will reflect the geometry of the culvert.
6. Compare the depth of flow from step 4 to
step 5. Adjust the culvert dimensions until the post-developed condition flow depth (Step 5) is lower than or equal to the pre-developed flow depth (Step 4).
7. Add flood plain culverts if required (see
section 1105.2.4).
8. Determine if the culvert meets the required hydraulic design controls. Upsize the culvert as required
1105.2.2 Depressed Culvert Inverts
Provide depressed inverts for all culverts designed to convey the Bankfull Discharge
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Design. In addition, use depressed culvert inverts when replacing culverts with existing natural channel bottoms with precast reinforced concrete box culverts.
Depressed culvert inverts will produce a natural channel bottom within the culvert. The natural channel bottom provides a substrate for passage of migratory species. The depressed culvert will fill naturally, such that the channel bed in the culvert will be continuous with the adjacent channel sections. Verify that the culvert meets the required hydraulic design controls realizing that the portion of the culvert depressed will eventually fill with natural substrates. Upsize the culvert as required. End treatments for culverts with depressed inverts consist of Item 601 Riprap, 6” Reinforced Concrete Slab with a cutoff wall on both inlet and outlet ends. See standard construction drawing DM-1.1 for details. Depress the culvert invert according to Table 1105-1: Table 1105-1
Type A Conduit Invert Depression
Pipe Diameter or Rise Depression <36” None
36”-60” 6” 66”-120” 12”
126”-180” 18” 186”-252” 24”
>252” 30” Modifications to the standard headwalls are not necessary for the depression depths noted above. Depressed inverts are not required for precast reinforced concrete three-sided flat -topped culverts with a natural channel bottom. 1105.2.3 Paved Depressed Approach Aprons
In many cases, the hydraulic operation of a culvert can be improved by depressing the flowline at the entrance below the channel flowline. The drop-down will alleviate a minimum cover condition, provide for additional headwater depth, and decrease the culvert outlet velocity by reducing the culvert slope.
The abrupt change in natural channel slope is effected with a short length of concrete paving to prevent downcutting of the stream. The dimensions of the slab are site specific. However, for ease of construction, a 2:1 downslope (4:1 preferred) should be used as the maximum descending slope. A 3-foot length of paving should be provided along the natural channel slope prior to the drop-down. A cut-off wall must be provided at the upstream end. In general, limit drop-down entrances to 4 feet, or one pipe diameter or rise, whichever is greater. The Federal Highway Administration has conducted extensive research and studies of paved depressed approach aprons, and recommended design procedures are included in Hydraulic Design Series No. 5, "Hydraulic Design of Highway Culverts." 1105.2.4 Flood Plain Culverts
For all new bankfull culvert installations, consider the use of flood plain culverts. In wide flood plains, the installation of a new single culvert constricts the flow of water at the entrance section. The concentrated outflow from the culvert can initiate downstream channel degradation. Flood plain culverts can be used to minimize the effects of this new concentrated discharge by spreading the discharge throughout the flood plain or flood prone area on the outlet side of the culvert. Provide flood plain culverts when the flood plain width is greater than two (2) times the width produced by the bankfull discharge design. Flood plain culverts are installed adjacent to the single culvert. Place flood plain culvert inverts at the water surface elevation that is generated by the bankfull discharge design. Locate the flood plain culverts within the flood plain at a location well beyond the single culvert. Furnish a minimum of two flood plain culverts. Figure 1102-2 illustrates the location of flood plain culverts with respect to the bankfull channel and flood plain. Flood plain culverts are not hydraulically designed or accounted for in the hydraulic design of the single culvert. Use Figure 1002-1 (“other” column) to determine the required diameter. The line and grade of the culvert should approximate that of the natural flood plain.
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1005.2.5 Energy Control Structures
Provide energy control structures for all culverts with an outlet velocity greater than five feet per second. The use of energy control structures does not constitute water quantity treatment for post-construction BMP purposes. An energy control structure reduces the amount of erosive energy generated by a culvert. Use the following for an energy control structure:
• Broken-Back Culvert • Rock Channel Protection • Energy dissipater (Riprap Basin) • Drop Structure
Provide an energy dissipater when the outlet velocity exceeds the values shown in Figure 1107-1. Energy dissipaters create a forced hydraulic jump within the structure or immediately downstream of the structure, thus reducing the flow velocity. FHWA Hydraulic Engineering Circular No. 14 provides design guidance and procedures for various energy dissipaters. The preferred energy dissipater is the riprap basin. Contact Central Office – Office of Production prior to using an energy dissipater. 1105.3 Types of Culvert Flow
Laboratory tests sponsored by the FHWA have established two general types of culvert flow: (1) flow with inlet control, or (2) flow with outlet control. Nomographs have been prepared for use in the determination of culvert headwater for the appropriate control. Under inlet control, the headwater “HWI” is directly related to the cross-sectional area of the culvert barrel and the inlet geometry. Under outlet control, the headwater “HWO” is further influenced by tailwater depth in the outlet channel and the slope, length and roughness of the culvert barrel. As shown in Figure 1105-1, culverts operate with a free water surface if the headwater is equal to or less than 1.2D, and with a submerged entrance if the headwater is greater than 1.2D, where D is the diameter or rise of the pipe. 1105.4 Design Procedure
1105.4.1 General
The design of a culvert involves a determination of the appropriate design and check discharges.
The process begins with a delineation of the drainage area, in acres [hectares], on a suitable topographic map. The design discharge “Q” for most culvert drainage areas will be obtained by procedures described in USGS Reports 89-4126 and 93-135, applying the limitations covered in Section 1003.1.2 of this manual. The Rational method should be used to obtain the discharge from small and other unusual drainage areas as noted in Section 1101.2.2 A representative cross-section of the embankment at the proposed culvert site, along with a profile of the natural stream or ground line, will be required to determine the approximate length and slope of the culvert. 1105.4.2 Hydraulic Analysis
The hydraulic analysis of a culvert, including a determination of the headwater depth and outlet velocity for the design discharge, is simplified by the use of Pipe Flow Charts and the headwater and head nomographs noted in Section 1105.4. The charts are included with the Drainage Design Aids, beginning with Figure 1100-200. To preclude the need for a determination of the probable type of flow under which a culvert will operate for a given set of conditions, the headwater depths may be computed using the nomographs for both inlet and outlet control. The size of pipe is then selected by using the control giving the higher headwater limitation. The relationship of the headwater to the diameter or height of the culvert “HW/D” is read directly from the inlet control nomograph and the HWI equals that value multiplied by D. HWO is computed by the equation HWO=H+ho - SoL.;/ The loss of head “H” is read from the flowing-full nomograph and the tailwater depth “ho”, is the greater of either the normal depth of flow in the outlet channel or the depth as flow passes through the outlet of the pipe, calculated as (dc+D)/2. D is the diameter or rise of the culvert and dc is the critical depth of flow which may be read from the critical depth curve shown on each Pipe Flow Chart. The above procedure is reasonably accurate for the majority of culvert flow conditions. For culverts operating with outlet control (see Figure 1105-1, Class 1-A and 1-B), where the calculated headwater (using the appropriate nomograph) is less than 0.75D, a backwater analysis can be justified and is recommended.
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A culvert analysis sheet similar to that provided in the Appendix shall be used to tabulate all the pertinent factors required to determine the controlling headwater for each culvert type being considered for a given location. The analysis sheet includes other information valuable to the reviewer and it is to be included with other supporting data for required review submissions. Hydraulic analysis of culverts may also be performed utilizing the Federal Highway Administration Hydraulic Design Series No. 5, Hydraulic Design of Highway Culverts. Computer programs such as FHWA HY-8 or ODOT’s CDSS software package may be used. CDSS may be downloaded from the Hydraulics website. For replacement projects, an analysis of the existing structure shall be performed. If appropriate (usually depending upon whether the structure is operating with a free water surface at its entrance), it is preferable that the same analysis method be used to compare the existing and proposed structures. For bridge replacements, acceptable methods of hydraulic analyses are listed numerically in preferred order as follows (the limitations of the method used shall be investigated prior to selecting it for use): 1. Computer Program HEC-2 (HEC-RAS) 2. Computer Program HY-7 (WSPRO) 3. Hydraulic Design Series No. 1, "Hydraulics of
Bridge Waterways", Federal Highway Administration, and computer program HY -4.
1105.5 Use of Nomographs
1105.5.1 Outlet Control
To determine the loss of head “H” for a given concrete pipe culvert with a grove-end entrance and discharge “Q”, proceed as follows: By straight line, connect culvert size with ke=0.2 (length scale) and obtain a point on the turning line. Connect the turning line point with the computed discharge “Q” and read the head loss “H”. Follow the same procedure for a corrugated metal pipe except using ke=0.9 (length scale). The ke value for additional shapes can be found in the Federal Highway Administration publication referenced in Section 1105.3.1. Should the roughness coefficient “n” of the proposed pipe differ from that shown on the chart, adjust the measured culvert length by the length
factor given on Design Aid Figure 1100-247. For an example, see Drainage Design Aid Figure 1100-247. The Federal Highway Administration publication referenced in Section 1105.3.1 offers nomographs for culvert shapes not available in the Drainage Design Aids. Their use is recommended for special culvert shapes. 1105.5.2 Inlet Control
To determine the headwater “HW” for a given discharge “Q”, size and type of culvert, proceed as follows using appropriate Figures 1100-245, 1100-246 (Drainage Design Aids). Use Figure 1100-245 for a round corrugated metal pipe culvert and Figure 1100-246 for a round smooth-lined pipe culvert. By a straight line, connect the culvert size with the discharge “Q”, extend a diagonal line to Scale (1) and thence by horizontal line to Scale (3). Based on a groove-end entrance and a Standard HW-2.1 headwall recommended for concrete pipe culverts, the HW/D relationship is obtained by an average of the (2) and (3) Scale values. Follow the same procedure for a corrugated metal pipe with a Standard HW-2.2 headwall, where HW/D is the average values read from Scales (1) and (3). Use Scale (2) for the HW/D relationship for concrete box culverts. 1105.6 Design Criteria
1105.6.1 Design Frequency
The design frequency shall be as stated in Section 1004.2 It should be noted that a Flood Hazard Evaluation using a check discharge based on the 100-year flood frequency shall be made for all culverts as noted in Section 1005.2.1. 1105.6.2 Maximum Allowable Headwater
See Section 1006. 1105.6.3 Method Used to Estimate Storm Discharge
See Sections 1003 and 1101. 1105.6.4 Scale of Topographic Mapping Used to Delineate Contributing Drainage Areas
See Section 1101.1
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1105.6.5 Manning’s Roughness Coefficient “n”
The “n” values for corrugated metal pipe are given in Figure 1105-2. The “n” value for all smooth flow pipe is 0.012. Use a weighted Manning’s n for bankfull designed culverts or analyzing older culverts with sediment deposition. 1105.6.6 Entrance Loss Coefficient “ke”
See Table 1105-2 or Appendix D of Federal Highway Hydraulic Design Series No. 5, "Hydraulic Design of Roadway Culverts. Table 1105-2
Type A Conduit Entrance Loss Coefficient ke
Type of Pipe Headwall Type Full One-Half None
Concrete, Vitrified (thick wall) *
0.2 0.2 0.2
Corrugated Metal (thin wall)
0.25** 0.9 0.9
* groove end entrance ** with beveled entrance
1105.6.7 Minimum Cover
See Section 1008 1105.6.8 Maximum Cover
See Section 1008 1105.6.9 Maximum Allowable Outlet Velocity
See Figure 1107-1 1105.6.10 Headwall Type
See Section 1106.2 1105.6.11 Contacts With County Engineer
Contact shall be made with the County Engineer at the beginning of the design process to ascertain ditch cleanout grades and watersheds, and the design shall be based on that information. Form LD-33 (available in the Appendix) shall be used to document approval. 1105.6.12 Minimum Pipe Size
As specified in Section 1002.3.1
1105.6.13 Ordinary High Water Mark
Calculate the OHWM using the 2 year depth of flow in the steam or channel or as determined by the Office of Environmental Services. 1105.7 Special Considerations
The following are special conditions that will be encountered in the hydraulic design of culverts that warrant clarification. Apply appropriate stream protection practices as described in Section 1105.2 when using special design considerations. 1105.7.1 Tailwater
Tailwater at a culvert outlet can greatly affect the size of culvert required at a specific site. For this reason a proper evaluation shall be made of the outlet channel so that a reasonable estimate of the tailwater can be calculated. A determination of the normal depth of flow in the outlet channel, when the culvert is discharging the design flow, normally establishes the culvert tailwater. A close examination of the downstream channel may however, reveal a temporary or permanent obstruction that will control the operation of the culvert. In some cases, the culvert will outlet near a river or other fluctuating water surface stream that could control its operation. Where that drainage area of the culvert is very much less than the receiving watercourse (i.e. 100 times) the effect of the receiving watercourse generally may be disregarded. Where the drainage areas of the culvert and receiving watercourse are nearly equal, concurrent flood peaks may be assumed. Where there is a significant, but not excessive, difference in the drainage area of the culvert and receiving stream, the following design procedure should be used and the culvert sized using the combination that results in the highest headwater. A. Compute the culvert headwater using the
proper design frequency for the culvert and a lesser frequency for the receiving stream water surface elevation (i.e. culvert tailwater elevation) depending upon the difference in drainage areas; say a 25-year culvert and a 10-year stream.
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B. Use 10-year frequency for the culvert and 25-year for the stream.
In some locations, a high tailwater will control the operation of a culvert to such an extent that a substantial increase in pipe size will be required for a negligible decrease in the headwater elevation. For this case, the culvert size should be based on a practical tailwater elevation (e.g. [dc+D]/2). 1105.7.2 Multiple Cell Culverts
A single-cell culvert should be the designer’s first choice within practical limitations. Occasionally, low headwater requirements, high fills, or bankfull design will create the need for multiple cells. For these cases, it is desirable to limit the number of cells to two. Experience has proven that multiple cells well aligned with a relatively straight channel, will operate satisfactory. However, a bend in the immediate upstream channel may cause the inside cell to collect debris during normal periods of runoff and thereby substantially reduce the capacity of the culvert. 1105.7.3 Improved Inlets
Consider improved inlets attached to the entrance end of the culvert to reduce headwater or culvert size. The improved inlet will alleviate a minimum cover condition and provide for additional headwater depth. Culverts on relatively steep slopes and controlled by inlet control can see a reduction in the culvert size by furnishing an improved inlet. Consider the following two general types of inlets in the following order: A. Side-taper - A tapered end section from a
round to an oval shape for a pipe, or a square to a rectangular shape for a prefabricated box. The length of the taper section is usually made 1.5 times the diameter or rise of the culvert.
B. Slope-taper - A combination of side-taper
preceded by a drop in the culvert flow line. The drop can be similar to a paved drop-down entrance or a more sophisticated reinforced concrete drop provided by a formed cast-in-place section with vertical sides.
The improved inlet has the advantage of admitting more flow and thereby tending to fill the
culvert barrel and reduce the culvert outlet velocity. The savings in culvert cost must justify the additional cost of the improved inlet. The Federal Highway Administration has conducted extensive research and studies of improved inlets, and recommended design procedures are included in Hydraulic Engineering Circular No. 13, "Hydraulic Design of Improved Inlets for Culverts."
1106 End Treatments
1106.1 General
Headwalls, or other approved end finishes, shall be provided at the open ends of all Type A, B and C conduits. Headwalls should also be provided for Type D conduits greater than 24 inches in diameter or rise. Generally, headwalls are not recommended for Type E and F conduits. In order to reduce the entrance loss in culverts, the bell end should be located upstream and the spigot end should be located downstream. Details shown in the plan should convey this to the Contractor when necessary. Figures 1106-2 and 1106-3 show typical end details for a concrete box culvert. 1106.1.1 Usage
The selection of the headwall type is based on safety and economics. Standard HW-2.1 and 2.2 half-height headwalls are recommended for round, elliptical, or pipe arch culverts where a clear zone is provided. Full height headwalls should be provided where a significant reduction in culvert length can be realized with large-span culverts (10 feet or greater) with foreslopes flatter than 2:1 or where right-of-way limits the culvert length. Full-height headwalls shall be provided for prefabricated box culverts and three-sided structures. The use of special end treatments may be required by Section 602.6 of Volume 1, Roadway Design. Details are available from the Hydraulic Section, Office of Structural Engineering. Justification for the use of this type of end treatment shall accompany the request for details. Miter-cut (step-bevel) end sections, when required, shall be shown on the Culvert Detail Sheet. When half-height headwalls are provided, they should be built perpendicular to the end of the conduit to eliminate the need for a skew cut. In addition to the required headwall, the upper, or
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exposed, half of conduits having a diameter or rise greater than or equal to 126 inches shall be miter-cut (step-bevel) to fit the embankment slope. 1106.1.2 End Treatment Grading
The prevailing embankment slope shall be projected to the back edge of the top of the headwall to establish the required culvert length as shown in Figure 1106-1. When the roadway foreslopes are flatter than 2:1, a 2:1 slope shall be provided from the back edge of the top of the headwall to a minimum of 1 foot, with 2 feet preferred, above the top of the culvert. The change in embankment slope shall be warped on each side of the conduit to fit the prevailing slope. In no case shall the distance from the pavement edge to the point where the embankment slope changes to 2:1 be less than the design clear zone width (see Section 601, Volume 1, Roadway Design) unless guardrail is provided. Clear zone grading should only be provided at culverts when the requirements of Section 307.21 of Volume 1, Roadway Design are met. The prevailing embankment slope shall be warped on either side of a skewed culvert to assure equivalent soil loading and proper side support of the pipe. This is especially true for flexible pipes with large skews and/or large diameters. 1106.2 Headwall Types
1106.2.1 Half-Height Headwalls
If the size of the conduit exceeds that shown in the Standard Construction Drawing HW-2.1 and HW-2.2 tables, the dimensions shown in the tables may be expanded to accommodate the larger size conduits. Payment for half-height headwalls shall be on a cubic yard basis for Item 602, Concrete Masonry. Masonry quantities for standard half-height headwalls may be obtained from the appropriate standard construction drawing. The quantity of concrete masonry provided in the plans shall be based on the pipe alternate requiring the largest quantity of concrete masonry. 1106.2.2 Full-Height Headwalls
The appropriate full-height headwall for round pipes shown on Standard Construction Drawing HW-1.1 may be considered at the entrance end, when the savings in the reduced size and length
of the conduit will offset the additional cost of the headwall. This will most likely apply where corrugated steel pipe is specified, due to cover or size requirements, and the bevel provided for the full-height headwall will substantially reduce the entrance loss. Dimensions of full-height headwalls may be expanded to accommodate pipe sizes larger than 84 inches. Design full-height headwalls for box, 3-sided and arch culverts per Section 300 of the Bridge Design Manual and the latest “AASHTO LRFD Bridge Design Specifications”. Payment for non-standard full-height headwalls is on a cubic yard basis for Item 511 or Supplemental Specification 898 and pounds of Item 509. Subdivide the quantities for non-standard full-height headwalls in to quantities for headwalls, wingwalls and footers and add plan note D118 to the plans. Include appropriate plan notes from Section 600 of the Bridge Design Manual in the project plans. An investigation of the supporting foundation material shall be conducted and the bearing capacity of the foundation material estimated. The level of detail required for the foundation investigation shall be commensurate with the importance of the structure. Such information shall be submitted for all proposed full-height headwall installations and submitted prior to the Stage 3 review. The inlet wingwall footings of full-height headwalls shall be armored with Type B rock channel protection, with filter, to preclude scour. 1106.3 Concrete Apron
Provide a reinforced concrete riprap cutoff wall, as shown on Standard Construction Drawings DM-1.1 when the depth of the rock channel protection (if necessary), including the 6 inch granular filter, exceeds the depth of the headwall. Provide concrete riprap at the inlet end of the culvert where the existing culvert has been undercut. Concrete riprap shall be in accordance with Section 1105. 2.3. Concrete riprap is not necessary at the inlet of culverts with full height headwalls that have a footing toe extending 3.5 feet or more below proposed channel grade.
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1107 Rock Channel Protection
1107.1 General
Rock channel protection is used to control erosion at the outlet of culverts and storm sewers, or for lining ditches on steep grades. It is used as a scour countermeasure at the inlet wingwalls of full-height headwalls and along the footings of 3-sided structures. 1107.2 Types
There are four types of rock channel protection (RCP) that are used in various situations. The use of the proper type at culvert and storm sewer outlets can be determined from Figure 1107-1. Type A is generally used beyond the outlet of the larger conduits having outlet velocities in excess of 12 feet per second and Type B and C for conduits having an aggregate filter where the protected slope is steeper than 3:1. A filter should always be specified to prevent soil piping through the rock. A fabric filter is preferred in most cases. An aggregate filter should be used when the RCP is under water. The cost of the filter is included in the unit bid price for Item 601 Rock Channel Protection with Filter.
1108 Agricultural Drainage
1108.1 Farm Drain Crossings
Where it is necessary to continue an existing farm drain crossing under the highway, the pipe shall be Type B Conduit, one commercial size larger than the existing farm drain within the right-of-way limits. Occasionally, it will be desirable to provide a farm drain crossing under a highway on new location to satisfy the future need for adequate farm drainage. It is recognized that the required length of a Type B Conduit will provide a betterment for the property owner, but it does preclude the need for a much more expensive crossing after the highway is built. Such a crossing is considered a “blind” and the cost of the installation, including suitable terminal markings at the right-of-way lines, will generally not be eligible for federal participation. 1108.2 Farm Drain Outlets
Existing farm drains that outlet through the backslope of the roadway ditch shall terminate with a minimum length of 10 feet of equivalent size Type F conduit. When outletting existing
plastic farm drains, one size larger Type F conduit shall be used. An Animal Guard and Erosion Control Pad as shown on Standard Construction Drawing DM-1.1 shall be provided. To provide for possible sedimentation, the invert of the Type F conduit shall be a minimum of 6 inches, with 12 inches being desirable, above the ditch flow line.
1109 Longitudinal Sewer Location
1109.1 Under Pavement
Longitudinal sewers will not be permitted under the pavement of a limited or controlled access facility. Also, the length of transverse sewers under pavements shall be held to a minimum, with no manholes allowed in the pavement. For other facilities, storm sewers should be located outside the limits of the pavement. However, in locations where this would create conflicts with existing utilities (e.g. waterlines, sanitary sewers, gas lines, etc.) the storm sewer may be located under the pavement. Care should be taken to avoid placing manholes in vehicle wheel-paths or within an intersection. The center of the curb lane is the preferred manhole location. Where an out -to-out clearance of 5 feet cannot be provided between parallel storm and sanitary sewers, premium joints shall be provided on the storm sewer. 1109.2 Under Paved Shoulder
The above shall also apply to paved shoulder areas, unless it is determined that the cost of any other possible location is prohibitive. 1109.3 Approval
Exceptions to the above shall be submitted in the early stages of the design to the Hydraulic Section, Office of Structural Engineering for review and approval.
1110 Reinforced Concrete Radius Pipe and Box Sections
1110.1 General
To comply with the capabilities of manufacturers to provide satisfactory and economical radius
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pipe or box sections, a minimum radius of 100 feet shall be specified. The method of manufacturing the radius pipe or box sections will be an option of the producer, subject to inspection and approval by the Ohio Department of Transportation, Office of Materials Management. As an alternate to radius pipe, pipe specials may be specified to negotiate the specified radius, provided they do not reduce the hydraulic performance established by the initial design. The bends shall be located so that they shall closely follow the alignment of the radius pipe.
1111 Sanitary Sewers
1111.1 General
Any sanitary sewer, whether new or relocated, shall be constructed using resilient and flexible gasket joints, in accordance with Construction and Material Specification 706.11 for circular concrete pipe or 706.12 for clay pipe. Permissible thermoplastic pipes shall also be specified. Discharges of treated sanitary flow from abutting property into highway drainage systems are only permitted if the discharge is authorized by the Local Health Department. 1111.2 Manholes
All new manholes for sanitary sewer lines shall be built in accordance with the Standard Construction Drawings. Precast manholes shall have joints in accordance with 706.11 of the Construction and Material Specifications.
1112 Notice of Intent (NOI)
1112.1 General
A NOI is a one-page application form for requesting coverage under a general permit for storm water discharges from Ohio EPA. The applicant(s) must certify their intention to comply with a general permit by submitting a NOI. Submit a NOI for all projects where combined Contractor and Project Earth Disturbing Activity (EDA) are one acre or more. In addition, when the combined Project and estimated Contractor EDA are just less than one acre, the project designer may choose to increase the estimated
Contractor EDA to avoid the possibility of work on the project being initiated without a NOI. Earth disturbing activity is defined as any activity that exposes bare ground or an erodible material to storm water and anywhere Item 659 Seeding, SS 870 Seeding, Item 660 Sodding, or SS 870 Sodding is being furnished. Routine Maintenance Projects, as defined by Section 1112.2, do not require a NOI. The Total Earth Disturbing Activity acreage, which includes the Project Earth Disturbing Activity acreage (earth disturbed area within the project construction limits) and the Contractor Earth Disturbing Activity acreage such as: field offices, batch plants, and borrow/waste pits, shall be estimated. The location and size of the Contractor Activities can be estimated using the NOI Acreage Calculation Form (Figure 1112-1). Non-contiguous portions of projects sold under one contract, such as multiple culvert replacements, may be treated as separate projects for the purposes of obtaining an NOI. If the project sites are located ¼ mile or more apart and the areas between the activities are not being disturbed, the sites can be considered separate. If each site is below the project earth disturbed area threshold of one acre of EDA, no post-construction BMP or NOI will be required. If one or more individual sites meet the project earth disturbed area thresholds, an NOI is required for the sum of areas that exceed the EDA threshold. Post-construction BMPs will be required only at the individual project sites that exceed the Project EDA threshold. Non-contiguous multiple part projects (i.e. Part 1/Part 2) sold as one project should be evaluated with respect to each Part. Parts that meet the definition in Section 1112.2 for Routine Maintenance Projects or have a project EDA under one acre do not need to be included in the disturbed acreage calculations for determining the need for a NOI or post-construction BMP. Post-construction BMPs will be required only at the individual parts that exceed the Project EDA threshold. Follow standard NOI procedures for a Project Part with routine maintenance activities exceeding five acres or a Project Part that includes construction (non-routine maintenance) activities. Use the calculated acreages for the Project Site Plan as required by Location and Design, Volume 3, Section 1308.
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1112.2 Routine Maintenance Project
For the purposes of submitting for coverage under an NPDES permit, a Routine Maintenance Project is one in which all of the Project Earth Disturbing Activities are routine operations that do not change the line, grade, or the hydraulic capacity of the facility and involve total earth disturbing activities of less than 5 acres. Permanent erosion control items shall be included in the plans, if required. Projects with five or more acres of earth disturbed area cannot be classified as Routine Maintenance Projects for purposes of determining NOI and post-construction BMP requirements, regardless of work type. The following activities are considered routine maintenance activities:
• Abutment Repairs - repairs to bridge abutments
• Bridge Deck Overlays - replacing the wearing surface on bridges
• Bridge Deck Replacement - replacing the entire deck on bridge
• Chip Sealing - placing asphalt or polymer binder and stone on existing paved roadways
• Partial Depth Pavement Repairs - isolated repairs of surface courses of pavement
• Linear Grading - reshaping of graded shoulders to establish proper drainage away from pavement
• Berm Repair or Topsoil placement along shoulders - placing berm material or topsoil on shoulders adjacent to pavement to eliminate drop-offs.
• Ditch Cleanout - maintaining or restoring original flow line and cross-section only
• Guardrail Installation / Replacement - installing / repairing with minor grading work to create proper grade for end assemblies where previous guardrail existed.
• Culvert Replacement - replacing a culvert with same line, grade and hydraulic capacity; just be within parameters of the USAC Nationwide Permit #3.
• Culvert Repair / Lining - repairing or lining existing culvert maintaining same line, grade and hydraulic capacity, must be within parameters of the USAC Nationwide Permit #3
• Resurfacing - replacing several inches of asphalt wearing course by milling existing asphalt and replacing with new.
• Curb Repairs - repairing existing curbing along a roadway.
Post construction storm water best management practices are not required for routine maintenance projects. 1112.3 Watershed Specific NOI Requirements
Additional requirements for projects located in certain designated watersheds are required by Ohio EPA. These projects require coverage under an Ohio EPA watershed specific NPDES permit. Coordinate projects in the following watersheds with Central Office – Office of Production:
• Big Darby Creek (entire watershed) • Olentangy River (portion of watershed as
regulated under permit number OHC200001)
In addition to post-construction BMP requirements, watershed specific NPDES permits include the following requirements:
• Groundwater Recharge Mitigation, if applicable
• Riparian Setback Mitigation • Temporary Sediment Basin Locations • Ohio EPA review and approval of the
Storm Water Pollution Prevention Plan (SWPPP)
Provide groundwater recharge calculations, riparian setback calculations, and temporary sediment basin locations to Central Office – Office of Production with the BMP submittals as outlined in Section 1116.2. Groundwater recharge calculations and riparian setback
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calculations shall be based on impacts outside the existing roadway right-of-way. Determine the riparian setback limits according to the Permit and identify the setback limits on the Project Site Plan. Mitigation for groundwater and riparian setback will be determined through coordination between Central Office – Office of Production and Ohio EPA prior to submittal of the NOI application. Determine soil types required for groundwater recharge calculations using soil survey maps or the NRCS Web Soil Survey website. While sediment basin locations are typically provided by the Contractor, designers of projects being developed under watershed specific NPDES permits shall identify locations with capacity to store sediment volumes required by the permit. The location and calculations for the sediment basins shall be shown on the Project Site Plan. Additional temporary sediment and erosion control features will be added to the SWPPP by the Contractor.
1113 Erosion Control at Bridge Ends
1113.1 General
For the purpose of reducing problems of erosion in the vicinity of bridge ends, details as shown on Standard Construction Drawing DM-4.1 shall be followed. At locations where the design flow exceeds 0.75 cubic feet per second, catch basins should generally be provided. 1113.2 Corner Cone
Item 670 Slope Erosion Protection shall be placed on all bridge approach embankment corner cones, beginning at the edge of the crushed aggregate or concrete slope protection.
1114 Temporary Sediment and Erosion Control
1114.1 General
Temporary sediment and erosion control is required on all projects that have Earth Disturbing Activities as outlined in Supplemental Specification 832. A Storm Water Pollution Prevention Plan (SWPPP) is required for all projects that require a NOI (See section 1112)
The SWPPP requirements are outlined in Supplemental Specification 832. 1114.2 Cost Estimate for Temporary Sediment and Erosion Control
For all projects that require temporary sediment and erosion control furnish an amount to be encumbered in the project final package. Use the temporary sediment and erosion control estimator located in the Design Reference Resource Center to develop this amount. Furnish the calculations with the final plan package.
1115 Post Construction Storm Water Structural Best Management Practices
1115.1 General
Post Construction Storm Water Best Management Practices (BMP) are provided for perpetual management of storm water runoff quality and quantity so that a receiving stream’s physical, chemical and biological characteristics are protected and stream functions are maintained. BMP, as described in Section 1117, shall meet or be equivalent in treatment effectiveness when compared with the BMP presented in Ohio EPA’s NPDES General Permits. For ODOT projects, any proposed alternative BMPs that are not found in Section 1117 require submittal to ODOT Central Office – Office of Production. A review and approval of the alternative BMP by ODOT Central Office – Office of Production and Ohio EPA is required. Local-Let Local Public Agency projects may use an alternative post-construction BMP policy with Ohio EPA approval. Post-construction BMP remove pollutants from runoff (water quality treatment) and protect streams by attempting to maintain existing stream conditions or by reducing runoff volumes through structural BMP (water quantity treatment). Locate BMPs so that they are protected in accordance with Location and Design Manual, Volume 1. 1115.2 Project Thresholds for Post-Construction BMP
Post-construction BMP are required through Ohio EPA’s NPDES General Permit for construction storm water discharges. The requirements to
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provide post-construction BMP established in the NPDES General Permit are based on Project Earth Disturbing Activities. If a NOI is not required (Section 1112), then post construction BMPs are not needed. Project Earth Disturbing Activity (EDA) is defined as any activity that exposes bare ground or an erodible material to storm water and anywhere Item 659 Seeding, SS 870 Seeding, Item 660 Sodding, or SS 870 Sodding is being furnished. An area where pavement is being removed to the sub-grade is considered earth disturbing activity, except for isolated repairs. Requirements based on project EDA for non-routine maintenance projects are listed below: Table 1115-1
Project Earth Disturbed Area Thresholds
• EDA < 1 acre - BMP and NOI not
required. • 1 acre = EDA < 5 acres - BMP required
unless coordinated through Central Office – Office of Production for evaluation by Ohio EPA.
• EDA ≥ 5 - BMP are required • Routine Maintenance projects as
defined in Section 1112.2 do not require post -construction BMP.
Provide post-construction BMP for all projects exceeding the project EDA thresholds. For projects requiring post-construction BMP, refer to Section 1115.6 to determine the level of treatment necessary. ODOT-let and Local-Let Local Public Agency (LPA) projects are required to provide post-construction BMP as indicated in Table 1115-1. Projects with post-construction BMP may require coordination with LPAs when BMPs are required outside ODOT right -of-way. Inform the LPA of maintenance responsibilities associated with post-construction BMP. Non-contiguous portions of projects sold under one contract that do not require an NOI, as described in Section 1112.1, do not require post-construction BMP.
1115.3 Water Quality and Water Quantity Treatment
Address water quality (pollutant removal) and water quantity (stream protection/volume control) for projects that require post-construction BMP. BMP to address water quantity are not required for projects that meet any of the following criteria:
• Sites where one or less acre of new impervious area is created in new permanent right-of-way area being acquired for the project.
• Site is a redevelopment project within an ultra-urban setting. Redevelopment projects include construction projects on land where impervious surfaces had previously been developed and where the new land use will not increase the runoff coefficient. See Section 1115.6.
• Sites which discharge directly to a large river (>100 square mile drainage area or fourth order or greater) or to a lake and where the development area is less than 5 percent of the watershed area upstream of the development site, unless known water quality problems exist in the receiving waters. If there is a question regarding the stream classification, contact Central Office - Office of Production.
BMP that treat water quality and water quantity include:
Water quantity (stream protection) treatment can also be provided through the use of paved depressed approach aprons, depressed inverts, and other grade control structures at stream crossings. See Section 1105 for further information.
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1115.4 Water Quality Volume
The water quality volume (WQv ) is used to define the amount of storm water runoff from any given storm that should be captured and treated in order to remove a majority of storm water pollutants on an average annual basis. The following equation shall be used to calculate the water quality volume:
WQv = (P*A*Cq)/12 Where,
WQv = Water Quality Volume (Acre-feet) P = Precipitation (0.75 inches) A = Contributing Drainage Area (acres) Cq = 0.858i3 - 0.78i2 + 0.774i + 0.04
(see figure 1115-1)
i = impervious area divided by the total area (use 0.9 within existing roadway right-of-way for calculation purposes)
Cq = 0.9 when all drainage area is
impervious. Water quality volume is directly used to determine sizing for the following BMP:
The water quality flow (WQf ) is the discharge that is produced by using an intensity of 0.65 in/hr in the rational equation (section 1101.2.2). Use the entire contributing drainage for the WQf calculation. Use water quality flow to determine sizing for manufactured systems. 1115.6 Redevelopment and New Construction
With respect to post-construction storm water BMP, redevelopment projects include projects
with limited addition of impervious surface. Redevelopment projects will not result in an increase to the runoff coefficient. While all areas within existing ODOT right -of-way may not be covered by impervious surfaces, the area within existing ODOT right-of-way is considered impervious area for the purpose of post-construction BMP calculations. Therefore, consider all area within existing right-of-way to be impervious with a runoff coefficient of 0.90 when performing post-construction BMP calculations. ODOT projects that do not require acquisition of new right-of-way are considered redevelopment projects. 1115.6.1 Treatment Requirements for Redevelopment Projects
Redevelopment projects utilizing BMPs designed based on WQv or WQf require treatment according to one of the following:
• Treat 20% of the WQv or WQf for 100% of the project
• Treat 100% of the WQv or WQf for 20% of the project earth disturbed area
Redevelopment projects utilizing Vegetated Biofilters require treatment as follows:
• Treat 100% of the contributing drainage
area for 20% of the project earth disturbed area in a specified portion of the project. For example, a project with 10 acres of project EDA may provide treatment through the use of a vegetated biofilter with 2 acres of contributing drainage area. The vegetated biofilter design would be based on the contributing drainage area to the ditch of 2 acres.
Redevelopment projects utilizing Exfiltration Trenches require treatment according to one of the following:
• Multiply the required length of ExT by
20% for 100% of the project • Use standard ExT length for 20% of the
project earth disturbed area For all scenarios, size the BMP based on the entire contributing drainage area, offsite and on-site, to the BMP.
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When providing treatment based on a percentage of the project earth disturbed area, consider the following:
• Credit for water quality and water quantity treatment is only applied to the portion of the contributing drainage area within ODOT right -of-way (on-site). Any offsite contributing drainage area must be included in the BMP calculations for sizing purposes (i.e. width of ditch, length of ExT, etc.). However, the offsite area will not be included in the reduction of the required amount of project EDA that requires treatment. Example: A vegetated biofilter that has offsite contributing drainage area of one acre and on-site contributing drainage area of two acres would result in a reduction of the required treatment area by two acres. The vegetated biofilter must be sized for the total contributing drainage area of three acres. Multiple areas of a project may provide treatment to meet the total area required for compliance with the NPDES Permit. If the total area requiring treatment in this example was 4 acres, another vegetated biofilter with a minimum of two acres of on-site tributary area would be needed.
• For projects with multiple distinct stream
crossings that do not immediately share a common confluence downstream, provide post-construction BMP treatment proportional to the amount of Project EDA tributary to each stream.
1115.6.2 Treatment Requirements for New Construction Projects
All projects that do not meet the definition of redevelopment are considered new construction. New construction projects allow for a reduction of treatment based on existing impervious area. New impervious area requires treatment of 100% of the area. Existing impervious area, including all existing right-of-way area, requires treatment of 20% of the area. Consider all area within existing ODOT right -of-way to be impervious for post-construction BMP calculations. Determine the Treatment Percent (weighted average of impervious areas for a drainage area) using the following equation: T = [(Aix * 0.20)+(Ain * 1.00)] / (Aix+Ain)
Where,
T = Treatment percent (decimal)
Aix = Existing impervious area (acres)
Ain = New impervious area (acres)
The Treatment Percent determined above shall be used to determine treatment in the same manner as described for redevelopment projects (i.e. Treat the Treatment Percent of WQv for 100% of Project EDA, etc.).
1116 BMP Selection and Submittals
1116.1 BMP Selection
Selection of BMP shall be based on providing maximum runoff treatment while minimizing impacts to the remaining project design features, including utilities and right-of-way. For curbed roadways, total contributing drainage areas to sumps or intersections that are less than or equal to 0.25 acres as shown in figure 1116-1 do not require a BMP. Note that these exceptions are unique circumstances. Provide BMP as necessary for all other project features. Projects where roadway drainage sheet flows off the roadway and continues outside existing or proposed right-of-way shall not channelize flow for the sole purpose of providing a post-construction BMP. Treatment is not required for areas where sheet flow off the roadway continues to sheet flow outside ODOT right-of-way. Areas where this occurs should be documented in the post-construction BMP calculations and identified on the Project Site Plan. Design criteria for all BMP are available in Section 1117. A flow chart to determine BMP treatment requirements is provided in Figure 1115-2.
1116.2 BMP Submittals
BMPs shall be considered early in the design process to allow for right-of-way and utility coordination as well as a waterway permit determination. For Major Projects, as classified through the PDP, requiring BMP, include a conceptual BMP layout as part of the Assessment of Feasible Alternatives submittal to ODOT Central Office – Office of Production during Step 6. Refine the conceptual BMP layout during Step 7. Submittal during Step 7 is optional.
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Develop the final BMP design no later than Step 8. For all major projects, submit documentation concerning BMP design during Step 8 to ODOT Central Office – Office of Production. Include the following information:
• Estimated Project Earth Disturbed Area • Determination of pre-construction and
post-construction runoff coefficient • Existing and Proposed amounts of
impervious area • BMP selected for use • Plan sheets showing locations of post-
construction BMP • Calculations for each BMP (Sec. 1117) • Explanation for any area that is not
For Minor Projects, as classified through the PDP, requiring BMP, include a conceptual BMP layout as part of the Preliminary Engineering submittal (Step 3). Submittal of the conceptual BMP layout for Minor projects to Central Office – Office of Production is optional. Develop the final BMP design no later than Step 4 for Minor projects. For all Minor project final BMP designs, submit documentation during Step 4 that consists of the same information requested for Major projects at Step 8 to ODOT Central Office – Office of Production. As early as possible in the design process, coordinate projects that do not provide BMP that treat the required percentage or area of the project (see Section 1115.6.1 and 1115.6.2) through ODOT Central Office – Office of Production for review and further coordination with Ohio EPA. Identify the final locations of post-construction BMP in the Project Site Plan as described in Section 1308 of Location and Design Manual, Volume 3. If applicable, provide cross-references to sheets showing post-construction BMP details on the Project Site Plan.
1117 BMP Toolbox
1117.1 Exfiltration Trench
An exfiltration trench (ExT) captures roadway drainage at the outside edge of shoulder through the use of a permeable concrete surface. The permeable concrete surface is placed parallel to
the roadway within a concrete structure. The ExT is placed a minimum of 15 feet prior to any drainage inlet, pavement catch basin (see figure 1117-1), or curb cut. Storm water is filtered through the ExT until it reaches a 4-inch perforated conduit connected to a 4-inch non-perforated outlet conduit. The 4-inch outlet conduit may discharge into a drainage structure or onto the slope using a reinforced concrete outlet. The ExT length is determined by the following equation:
Lt = (A*Cq)/689
Where, Lt = Required Permeable Length of
Trench (feet) Use a minimum length of 4 feet Length is in increments of 4 feet
A = Total Contributing Area (square feet) as determined according to Section 1103.3.
Cq = 0.858i3-0.78i2+0.774i+0.04 (see figure 1115-1)
i = impervious area divided by the total
area The length, Lt, may be reduced according to Sections 1115.6.1 and 1115.6.2.
Runoff bypassing the exfiltration trench is collected in the downstream catch basin or inlet. Therefore, once an area is treated, it may be removed from the next downstream ExT length calculation. See SCD WQ-1.2 for ExT payment information.
• Use Type A for curb and gutter, Type 2. • Use Type B for barrier and non-6-inch
curb. • Use Type C for 6 inch curb without gutter.
The following limitations apply to exfiltration trenches:
• Do not use the ExT in short tapers (less than 25 feet), parking areas, on a radius, or within a driveway.
• Do not use the ExT on the high side of a superelevated roadway.
• Do not use the ExT with shoulder widths less than 2 feet.
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See Figure 1117-1 for further ExT implementation details.
1117.2 Manufactured Systems
Manufactured systems consist of underground structures that treat the water quality flow (WQf ) by removing particulate matter through settlement. Supplemental Specifications 895 and 995 cover the material and performance criteria for these devices. They are placed in an off-line configuration with manholes to allow for routine maintenance procedures (see figure 1117-2). Provide a No. 3 Manhole, With ___” Base ID and ___” Weir where flow is to be diverted to the off-line manufactured system. Furnish two lengths of 603, Type B Conduit placed perpendicular to the inflowing sewer (see reserved area table for the total length required). Use Table 1117-1 when placing a Manufactured System: Table 1117-1
Manufactured Systems
Type WQf (cfs)
No. 3 Manhole Base ID (inches)
603 – Type B Conduit
Diameter (inches)
1 1 84 12 2 2 90 15 3 3 96 18 4 6 108 24
Reserve an area (as measured from the centerline of the No. 3 Manhole) according to Table 1117-2: Table 1117-2
Center the length of the area at the No. 3 Manhole. If this area is not attainable, contact Central Office – Office of Production for further guidance. Ensure this area is void of all utilities and is accessible for routine cleanout and maintenance. When a manufactured system is connected to a storm sewer with a depth exceeding 10 feet, contact Central Office – Office of Production.
Manufactured systems are typically not suited for treatment of flows in large trunk sewers. As shown in the figure above, manufactured systems should not be provided on sewers that are carrying a water quality flow greater than 6 cfs. The water quality flow calculation to determine the flow in the storm sewer shall be based on the entire contributing drainage area. 1117.3 Vegetated Biofilter
A Vegetated Biofilter (VBF) is a BMP that filters storm water through vegetation. The vegetated biofilter consists of the vegetated portion of the graded shoulder, vegetated slope, and vegetated ditch. When widening existing ditches, consider the following before purchasing new right-of-way:
• Provide a steeper ditch foreslope. • Provide a steeper ditch backslope. • Reducing the bench width to a minimum
of 4 feet. Consider soil conditions and safety issues prior to making any of the above changes to the existing slopes or benches. Changes to existing ditches may be regulated through waterway permits since ditches may be considered streams or wetlands. All impacts to existing streams and wetlands should be avoided or minimized to the maximum extent practicable. To determine if the proposed ditch will impact an existing stream or wetland, contact the District Environmental Coordinator. 1117.3.1 Vegetated Ditch Design Process
For projects utilizing ditch conveyance, provide a bottom ditch width using the Enhanced Bankfull Width (EBW) or “Standard” ditch width to provide water quality treatment. Use the following steps to determine the ditch width: A. Determine Enhanced Bankfull Width:
EBW = 5.4A0.356
EBW = Enhanced Bankfull Width (feet) A = Total contributing drainage area to the ditch (acres) The enhanced bankfull width corresponds to the dimension of the bottom width of the ditch.
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B. Determine “Standard” Ditch Width:
Determine the type and size of ditch that would typically be specified for the project without accounting for water quality treatment (use typical roadway design practices). 1. If using a Radius Ditch, refer to the “b”
dimension in Figure 307-2E of Location and Design Manual, Volume 1 to determine the bottom width of the ditch.
2. If using a trapezoidal ditch, use the bottom width dimension. Ignore any rounding lengths associated with the trapezoidal ditch.
C. Determine the vegetated biofilter ditch width
required for water quality treatment as described below:
1. If the EBW is less than or equal to the
”Standard” ditch width, furnish the “Standard” ditch.
2. If the EBW is greater than the “Standard”
width, furnish the EBW to a maximum bottom width of ten (10) feet.
The EBW can be calculated at multiple locations along its length. This would allow the width to be reduced where there is less tributary area (i.e. the upstream area of the ditch). However, the entire contributing drainage area to the location in the ditch being evaluated shall be considered whenever the EBW is determined. At points where concentrated offsite runoff is accepted, the EBW should be recalculated. Begin ditch width calculations at the outfall and move upstream through the drainage area. Ensure that rock or other impervious soil layers will not prevent vegetation from being established at the invert of the flowline. Constriction points in the enhanced bankfull width at drive pipes or other drainage related features are acceptable. A transition back to the calculated width shall be made immediately following the constriction point. 1117.4 Extended Detention
Extended detention is a method that captures storm water during rain events and slowly releases the captured volume over a period of time. The WQv is used to determine the storage
volume of the detention basin. The WQv is discharged over a 48 hour time frame. Increase the WQv by 20% when sizing the BMP to allow for sedimentation to occur. Detention can be either above or below ground. Detention basins that are above ground are the preferred choice and should be used when feasible. However, when project site parameters dictate, an underground system may be the optimum choice. 1117.4.1 Detention Basin
A detention basin is a dry pond that detains storm water for quality and quantity. The following criteria apply when designing a detention basin: A. Allow for 1 foot of freeboard above the
storage volume. B. Furnish a micro pool when feasible (see
figure 1117-5)
C. Use side slopes of 4:1 (max).
D. Ensure the design check discharge will safely pass through the structure (section 1117.4.3).
E. Vegetate the sides of the basin with Item 670
Slope Erosion Protection. F. Embankment work to create the
impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.
G. Consider vehicle access to the basin for
periodic maintenance. H. Do not locate on uncompacted fill or steep
slopes (2:1 or more) or where infiltrating ground water could adversely impact slope stability.
I. Furnish an anti-seep collar around the outlet
pipe. J. Furnish gravel pack protection at the outlet
structure (see SCD WQ1.1). K. Place channel protection (RCP or Concrete
Mat) at the entrance of the basin to minimize erosion and sediment resuspension.
L. Furnish a forebay that is approximately 10%
of the total design volume. M. Furnish a Water Quality Basin, Detention per
section 1117.4.1.1
Drainage Design Procedures
11-32 April 2010
1117.4.1.1 Water Quality Basin and Weir Furnish an outlet structure that fully drains the WQv in 48 hours or more. No more than 50% of the WQv should be released from the detention basin in less than one-third the drain time. The outlet structure consists of a catch basin with a perforated riser pipe on the inlet side and a conduit on the outlet side. The perforated riser pipe is used for flow control to achieve the required discharge time. A gravel envelope surrounds the perforated riser pipe along the inlet side of the catch basin to prevent blockage of the orifice holes in the pipe. The catch basin and riser pipe are paid for as Item 604, Water Quality Basin, Detention. Details of a perforated riser pipe outlet structure can be found on standard drawing WQ1.1. Furnish a weir to allow the design check discharge to bypass the structure without damage to the detention basin or embankment of the basin. The design check discharge shall be determined per 1117.4.3. The equation for a single orifice is:
Where, A = Area of orifice (ft2)
H = Head on orifice as measured to the centerline of the orifice (ft)
C = Orifice coefficient
Table 1117-3 Orifice Coefficient Guidance
C Description
0.66 Use for thin materials where the thickness is equal to or less than the orifice diameter.
0.80 Use when the material is thicker than the orifice diameter.
From CALTRANS, Storm Water Quality Handbooks, Project Planning and Design Guide, September 2002.
A hydrograph curve for the outlet will be required to calculate the discharge time of the WQv and the design check discharge (see 1117.4.3). The discharge time should correspond to the minimum drain time of 48 hours with no more than 50% of the WQv being released from the detention basin in less than one-third the drain time.
Generally, it is easier to model the outlet structure and discharge time using software such as Pond Pak or HydroCad to develop the hydrograph.
1117.4.1.2 Anti-Seep Collar Design Anti-seep collars shall be installed on conduits through earth fills where water is being detained. The following criteria apply to anti-seep collars: A. Furnish a minimum of 2 collars per outlet
conduit. Increase the seepage length along the conduit by a minimum of 15%. This percentage is based on the length of the pipe in the saturation zone.
B. Anti-seep collars should be placed equally within the saturation zone. Place one collar at the end of the saturation zone. In cases where the spacing limit will not allow this, place at least one collar within the saturation zone.
C. Maximum collar spacing should be 14 times the minimum projection above the pipe, but not more than 25 feet. The minimum collar spacing should be 5 times the minimum projection, but not less than 10 feet.
D. Extend the collar dimensions a minimum of 2 feet in all directions around the outside of the conduit, measured perpendicular to the conduit. Center the anti-seep collars around the conduit.
E. The top of collar shall not be less than 6 inches below, measured normal to, the finished groundline.
F. All anti-seep collars and their connections
shall be watertight. G. Minimum thickness shall be 6 inches. H. Payment for the collar shall be Item 602
Concrete Masonry (see standard construction drawing WQ-1.2).
The design procedure for anti-seep collars is as follows:
1. Determine the length of the conduit within the saturated zone. The assumed normal saturation zone can be determined by projecting a line through the embankment, with a 4:1 (H:V) slope, from the point where the normal water elevation (10-year) meets the upstream slope to a point where it intersects the invert of the conduit. This line, referred to
Q = A C. 64.4H.
Drainage Design Procedures
April 2010 11-33
as the “phreatic line”, represents the upper surface of the zone of saturation within the embankment (See Figure 1117-11). The 10-year storm pool elevation is the phreatic line starting elevation.
Ls = Y(Z+4)[1+S/(0.25-S)]
Where,
Ls = Length of the conduit in the saturated zone (feet) Y = Depth of the water at the spillway crest, 10-year frequency stormwater surface elevation (feet) Z = Slope of the upstream face of the embankment (Z feet horizontal to 1 foot vertical) S = Slope of the conduit (feet per foot)
2. Determine the required seepage length
increase.
∆Ls = 0.15Ls
3. Choose a collar height and width that is at least 4 feet larger than the outside diameter of the conduit (minimum projection of 2 feet from all sides of the conduit). Give collar sizes in one foot increments.
P = W – D
Where,
P = Projection of collar (feet) W = Height or width of collar (feet) D = Inside diameter of conduit
4. Determine the total number of collars
required. The collar size can be increased to reduce the number of collars. Alternatively, the collar size can be decreased by providing more collars. In any case, increase the seepage length by a minimum of 15%.
No. of collars required = ∆Ls/P
1117.4.2 Underground Detention
Underground detention areas are made up of a series of conduits. They range from an oversized storm sewer to a series of conduits that are specifically used for storm water detention. The following criteria apply when designing underground detention: A. Ensure the Hydraulic Grade Line design of
the storm sewer will pass through the structure and meet the requirements of 1104.4.2.
B. Consider access to the conduits for periodic
maintenance. C. If practical, provide pretreatment of the storm
water with vegetation. D. Payment for the conduit shall be: Item 603
____” Conduit, Type____, for underground detention.
1117.4.3 Design Check Discharge
A design check discharge with the frequency of a 10-year event shall be used. Use the entire drainage area that contributes to the BMP to calculate the design check discharge. 1117.5 Retention Basin
A retention basin is a “wet” pond that has a minimum water surface elevation between storms that is defined as the permanent pool. Above the permanent pool is a detention pool that provides storage for 75% of the WQv and drains in 24 hours or more. The full storage water depth is typically between 3-6 feet and the volume is less than 15 Ac-ft. The permanent pool is sized to provide storage for 75% of the WQv. A retention basin is ideal for large tributaries, but it may require a large amount of space. Consider the following when designing a retention basin: A. Use RCP at the inlet of the basin to provide
energy dissipation and erosion control. B. Allow for 1 foot freeboard above the WQv.
C. Use side slopes of 4:1 (max). D. Ensure the design check discharge will safely
pass through the structure (section 1117.4.3).
Drainage Design Procedures
11-34 April 2010
E. Use a length to width ratio of at least 3:1 to prevent short-circuiting.
F. Vegetate the sides of the basin with Item 670
Slope Erosion Protection. G. Furnish a forebay (7-10% of the total
retention volume) to extend the service life of the BMP when feasible.
H. Furnish an anti-seep collar around the outlet
pipe (see section 1117.4.1.2). I. Furnish a trash rack at the outlet structure. J. The underlying soils should be compacted to
prevent infiltration of the permanent pool or an impervious liner should be used.
K. Consider vehicle access to the basin for
periodic maintenance. L. Retention basin must be greater than 10,000
feet from a municipal airport runway. M. Embankment work to create the
impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.
N. Furnish a Water Quality Basin, Retention per
1117.5.1. 1117.5.1 Water Quality Basin and Weir
A retention basin outlet structure is designed similar to the outlet structure for a detention basin. The difference is that 75% of the WQv should be discharged out of the basin in 24 hours or more. No more than 50% of the WQv should be released from the detention basin in less than one-third the drain time. The outlet structures are of a similar type, except the openings will be set at a high enough elevation to maintain 75% of the WQv in the permanent pool (see standard construction drawing WQ-1.1). The catch basin and riser pipe is paid for as Item 604, Water Quality Basin, Retention. 1117.6 Bioretention Cell
Bioretention Cells consist of depressed low-lying areas that treat storm water through evapotranspiration and filtering through a planting soil. As the storm water passes through the soil it is filtered. An underlying perforated storm sewer or underdrain captures the treated storm water and carries it to an outlet. Extensive vegetation
assists in the filtration of the storm water prior to filtering through the soil. Vegetation should consist of shrubs or grasses that are native to the area. The existing soil must be removed and replaced when constructing a bioretention cell. The bioretention planting soil (plan note WQ101) should consist of a mixture of sand, topsoil, and compost. A bioretention cell is sized to store the WQv prior to filtration. Total filtration should occur in 40 hours or more. Use the following equation to determine the minimum surface area of the bioretention invert:
Where,
WQv = Water quality volume (see section 1115) (Acre-feet) T = Drain time of the cell, 40 hours K = permeability of the planting soil (Use 3.3 x 10 -̂5 ft/sec) A = Top surface area of the trench (Ac) D = Depth of the planting soil (ft) (4.0 feet minimum) h = Maximum depth of water above the cells top layer for the WQv (use 1 foot).
The following criteria apply when designing a bioretention BMP: A. Do not place where snow may be stored. B. Furnish 10 feet or less width between 4 inch
underdrain laterals. C. Furnish bypass or overflow for the design
check discharge. Use a catch basin(s) in conjunction with an overflow weir as needed.
D. Furnish pretreatment of the storm water via
vegetation. E. Ensure the water table or bedrock is below
the invert of the bioretention area. F. Use side slopes of 4:1 (max).
A = WQv D.
3600 K. T. h D( ).
Drainage Design Procedures
April 2010 11-35
G. Furnish a length to width ratio of 2:1 (min). H. Use a minimum depth of 4 feet of planting
soil. Provide at least 4 inches of depth deeper than the largest root ball.
I. Furnish an organic or mulching layer at the
top of the planting soil. J. Furnish a maximum depth of 1 foot to the
riser pipe or catch basin outlet from the mulching layer for storage of the WQv.
K. Furnish a bioretention cell as Item 203-
Special - Bioretention Cell. 1117.7 Infiltration
Infiltration techniques treat storm water through the interaction of a filtering substrate that consists of soil, sand, or gravel. This technique discharges the treated storm water into the ground water rather than into surface waters. Typically, infiltration practices are only suitable when Hydrologic Soil Group (HSG) Type A soils or, in some cases, HSG Type B soils exist. Infiltration methods require an extensive investigation of the existing soils and geology to ensure success. The investigation should begin with a preliminary soil evaluation of the project site early in the design process (PDP Step 7 for major projects and PDP Step 3 for minor projects). In-situ testing is not anticipated during the preliminary evaluation process. Use available soil and geology data found in the Soil and Water Conservation maps, United States Geological Survey (USGS), adjacent projects, or estimations from a geotechnical engineer. National Resources Conservation Service’s Web Soil Survey website may also provide soil and geology information. Material property tables for infiltration, permeability, and porosity have been provided for the preliminary evaluation (Tables 1117-4 & 1117-5). If the preliminary evaluation yields favorable results a more detailed evaluation should be performed. The detailed evaluation will require a geotechnical investigation of the underlying soils and geology. Soil borings should be performed to a maximum depth of 20 feet (or refusal) with samples taken every 5 feet for laboratory testing.
The number and location of soil borings should correspond with the approximate size (as determined in the preliminary evaluation) of the infiltration BMP and should be recommended by the geotechnical engineer. If the detailed evaluation yields favorable results, the ground water depth must be verified. The geotechnical engineer shall provide the seasonal high ground water depth. In some cases, observation wells may be installed and static water levels may be observed over a dry and wet season for verification. The infiltration and permeability rate of the soil shall be tested in the detailed soil evaluation at the discretion of the geotechnical engineer. In some cases, insitu testing at the proposed location of the infiltration BMP may be required. The following criteria apply to infiltration methods and must be met to be considered a feasible alternative: A. Design using the WQv as per Section 1115. B. Do not place infiltration BMP where snow
may be stored. C. The appropriate soil type must be present:
1. Infiltration must be greater than 0.50 in/hr and no greater than 2.4 in/hr.
2. Soils must have less than 30% clay or
40% of clay and silt combined.
D. The invert of the structure must be at least 4 feet above the seasonal high water table and any impervious layer.
E. Infiltration techniques are not suitable on fill
soil, compacted soil, or steep slopes (greater than 4:1). Consideration should be given to the long term impacts upon hillside stability if applicable.
F. Pretreatment shall be provided to remove
large debris, trash and suspended sediment to extend the service life. An example of pretreatment includes providing vegetated ditches prior to flow entering the infiltration facility.
1117.7.1 Infiltration Trench
An infiltration trench is an excavated trench that has been lined with a geotextile fabric and backfilled with aggregate. The storm water is
Drainage Design Procedures
11-36 April 2010
filtered through the aggregate and is stored within the pore volume of the backfill material. It is allowed to percolate through the sides and bottom of the trench. The drawdown time of the WQv is 24 hours or more. Consider the following when designing an Infiltration trench: A. The minimum acceptable permeability of the
surrounding soil is =6.5*10 -̂5 ft/sec or 2.8 in/hr (see Table 1117-4).
B. Design using the WQv as per Section 1115.
C. Long and deep infiltration trenches are most
efficient (3 feet bottom width and 3-6 feet deep).
D. Furnish a 6 inch layer of Item 601 Infiltration
Basin Aggregate on the top of the trench. E. The geometric shape of the trench is a
trapezoid with sides at a 1:1 (H:V) slope due to constructability. The top width is calculated as:
Top Width = Bottom Width + (2 * Depth)
F. Pretreatment using vegetation shall be
provided to ensure longevity of the infiltration trench.
G. An observation well shall be provided to
facilitate ground water level inspection. H. Locate the infiltration trench at least 1,000
feet from any municipal water supply well and at least 100 feet from any private well, septic tank, or field tile drains.
I. Ensure the bottom of the trench is below the
frost line (2.5 feet) The length of the trench depends upon the depth and the bottom width. The required length is calculated by assuming a depth and bottom width. The length is calculated based upon the inflow (WQv) and the outflow (ground water recharge). The following equation calculates the required length in feet:
Where,
WQv = Water quality volume (see section 1115) (Acre-feet)
T = Drain time through the sides of the trench, 24 hours K = permeability of the surrounding soil (ft/sec) (table 1117-4) D = Trench depth (ft) b = Bottom width of the trench (ft)
Table 1117-4 Permeability of Soil (K)
Soil Type Rate (K) (ft/sec)
Gravel 3.3x10-3 to 3.3x10-1 Sand 3.3x10-5 to 3.3x10-2 Silt 3.3x10-9 to 3.3x10-5
Clay (saturated) < 3.3x10-9 Till 3.3x10-10 to 3.3x10-6
From Urban Runoff Quality Management WEF Manual of Practice No. 23, 1998, published jointly by the WEF and ASCE, chapter five 1117.7.2 Infiltration Basin
An infiltration basin is an open surface pond that uses infiltration into the ground as the release mechanism. It is designed to store the WQv. Depending on the soil permeability, it may be used to treat from 5 to 50 acres. Lower permeable soils may require an underdrain system as an additional outlet. The drawdown time of the WQv should be between 24-48 hours. The following criteria apply when designing an infiltration basin:
A. Use an energy dissipater at the inlet.
B. Allow for 1 foot (min) freeboard above the WQv.
C. Vegetate the sides of the basin with Item
670 Slope Erosion Protection.
D. Furnish a 6 inch layer of Item 601 Infiltration Basin Aggregate on the bottom of the basin.
E. Use side slopes of 4:1 (max).
F. Use a length to width ratio of 3:1 G. Furnish bypass or overflow for the design
check discharge (see section 1117.4.3).
H. Consider vehicle access to the basin for periodic maintenance.
Drainage Design Procedures
April 2010 11-37
I. Locate basin at least 1,000 feet from any
municipal water supply well and at least 100 feet from any private well, septic tank, or drain field.
J. Furnish 10 feet or less width between 4
inch underdrain laterals (if used in the design).
K. Do not locate the basin where infiltrating
ground water may adversely impact slope stability.
L. Ensure the invert of any underdrain in the
basin is below the frost line (2.5 feet).
M. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, Using Natural Soils, 703.16.A.
The invert area of the infiltration basin can be calculated by the following equation:
A=(WQv * S.F. * 12)/(k * t) Where, A = area of invert of the basin (Acres)
WQv = Water Quality Volume (see section 1115) (Acre-feet)
S.F. = Safety Factor of 1.5 k = Infiltration Rate (in/hr) (table 1117-5)
t = Drawdown time of 48 hours
The required depth of the infiltration basin can be calculated by the following equation:
D = WQv/A Where, A = area of invert of the basin (Acres) WQv = Water Quality Volume (Ac-ft) D = Required depth of the basin (ft)
Table 1117-5
NRCS Soil Type (from soil maps)
HSG Classification
Rate (k)
(in/hr) Sand A 8.0 Loamy Sand A 2.0 Sandy Loam B 1.0 Loam B 0.5 Silt Loam C 0.25 Sandy Clay Loam
C 0.15
Clay Loam & Silty Clay Loam D < 0.09
Clays D < 0.05 Infiltration Rate (k)
From Urban Runoff Quality Management WEF Manual of Practice No. 23, 1998, published jointly by the WEF and ASCE, chapter five 1117.8 Constructed Wetlands
Constructed Wetlands treat storm water through bio-retention. They are depressed, heavily planted areas that are designed to maintain a dry weather flow depth ranging between 0.5 to 2 feet. The surface area required for a wetland is usually quite large due to the limited allowable depth. The area is usually on the magnitude of 1% of the entire drainage area. They are designed in a similar manner as a retention basin. The wetland is sized to provide storage for the WQv for a time frame of at least 24 hours (above the permanent pool) while providing a bypass or overflow for larger design check discharge (see section 1117.4.3). The water depth should be maintained by an outlet structure capable of providing the required water depth with the provision of a one foot freeboard. The following criteria apply when designing a Constructed Wetland: A. Do not place on a steep or unstable slope or
at a location, which could induce short-term or long-term instability.
B. Constructed Wetlands must be greater than
10,000 feet from a municipal airport runway. C. Base flow must be present to maintain the
constant water depth (such as ground water). D. Furnish a forebay that is 7% of the total
required volume at a depth between 3-6 feet to settle out sediments.
E. Furnish side slopes of 4:1 (max).
Drainage Design Procedures
11-38 April 2010
F. Consider access for maintenance to the forebay and the outlet structure.
G. Vegetate the sides and bottom with grass H. Furnish an impervious liner. Use a
compacted clay bottom or a geotextile fabric to prevent infiltration of the storm water.
I. Furnish a length to width ratio of 3:1 (min) to
prevent short-circuiting.
1100 Drainage Design Procedures – List of Figures
April 2010
Figure Subject 1101-1 Overland Flow Chart General Notes for Figures 1101-2 and 1101-3 1101-2 Rainfall Intensity-Frequency-Duration Curves 1101-3 Rainfall Intensity Zone Map 1102-1 Capacity of Grate Catch Basin in a Sump 1102-2 Channel Features 1103-1 Nomograph for Flow in Triangular Channels 1103-2 Capacity of Curb Opening Inlets on Continuous Grade 1103-3 Capacity of Standard Catch Basin Grates in Pavement Sags - Flow Through Grate
Opening 1103-4 Capacity of Inlets and Standard Catch Basins in Pavement Sags - Flow Through Curb Opening 1104-1 Type F, Broken Back Detail 1105-1 Classification of Flow in Culverts 1105-2 Corrugated Metal Pipe Sizes and "n" Values for Type A Conduits 1105-3 Example Bankfull Discharge Culvert Design 1106-1 End Treatment Grading Detail 1106-2 Box Culvert Outlet Detail 1106-3 Box Culvert Inlet Detail 1107-1 Rock Channel Protection at Culvert Storm Sewer Outlets 1112-1 Notice of Intent (NOI) Acreage Calculation Form 1115-1 Water Quality Cq 1115-2 Post-Construction BMP Treatment 1116-1 Exempt Outfalls 1117-1 Exfiltration Trench Detail 1117-2 Manufactured System Detail 1117-3 Vegetated Biofilter Detail 1117-4 Vegetated Ditch Design Example 1117-5 Conceptual Layout for Detention Basin for Water Quality 1117-6 Extended Detention Basin Example
April 2010
1117-7 Retention Basin Example 1117-8 Bioretention Cell Example 1117-9 Infiltration Trench Example 1117-10 Infiltration Basin Example 1117-11 Anti-Seep Collars
General Notes – Figures 1101-2 through 1101-3
April 2010
The Rainfall Intensity-Duration-Frequency curves are based upon data obtained from United States Weather Service Technical Paper No. 40 Rainfall Frequency Atlas of The United States. Federal Highway Administration Hydraulic Engineering Circular No. 12 Appendix A offers a methodology for converting I-D-F data points to an equation of the general form:
i= a/(t+b)^c
Where: i = rainfall intensity (inches/hour) t = time of concentration (minutes) a = constant b = constant c = constant Using the above referenced methodology the curves in Figure 1101-2 can be expressed using the above general equation utilizing the constants shown below.
Enter 0.125 for Type A; 0.25 for Type B; or 1.00 for Type CBatch Plant: Yes = 2.0; No = 0Off-Project Waste / Borrow Pit:
Add 1.0 acre per 15,000 CY of waste or borrowMiscellaneous Other Off-Project Areas:
Off-Project staging areas, stock yards, etc.Contractor Earth Disturbing Activities SubtotalTotal Earth Disturbing Activities (add Project EDA and Contractor EDA) TOTAL
NOI Earth Disturbing Activities (see below to determine value) TOTAL
Contractor Earth Disturbing Activities:
Off-Project Waste / Borrow - The specified estimation is based on approximately 10 feet of depth or fill over 1 acre. The designer may choose a different value based on knowledge of the project area, bedrock elevations, previous projects, etc. Consideration should be given for grindings, as well. (10ft. x 43560 s.f. / 27 = 16,133 c.y. ~ 15,000 c.y.)
Batch Plant - It is assumed that a typical batch plant would occupy 2 acres of ground. The designer should investigate the location of the project relative to existing plants, facilities, etc. to estimate whether a batch plant might be used by the Contractor. This is not needed for existing plants, it is only for plants set up for the specific project.
NOTICE OF INTENT (NOI) ACREAGE CALCULATION FORM1112-1
Field Office - These sizes were determined with regard to size of the trailer, parking, and some stock area for equipment and materials.
Project Earth Disturbing Activities - Enter the area of permanent earth disturbing activities directly related to project activities. Earth disturbing activity is defined as any activity that exposes bare ground or an erodible material to storm water and anywhere Item 659 Seeding, SS 870 Seeding, Item 660 Sodding, or SS 870 Sodding is being furnished.
If the project is a Routine Maintenance Project, an NOI is not required. (See Section 1112)
NOI Earth Disturbing Activities - This is the combined Project and Contractor Earth Disturbed Area. Based on project conditions and activities, some flexibility in the area calculation should be provided to avoid the possibility of the estimated work being less than the actual work. This scenario would require submittal of an NOI for projects originally calculated to be less than one acre during construction.
A Routine Maintenance Project consists of activities that do not change the line, grade, or hydraulic capacity of the existing condition and has less than 5 acres of earth disturbing activities (see section 1112.2).
For projects with an estimated NOI EDA less than one acre: No NOI is required. For projects with an estimated NOIEDA of one or more acre, but less than 4.9 acres, use 4.9 acres. For projects with an estimated NOI EDA greater than 4.9 acres, use the sum of the Project and Contractor Earth Disturbed Areas.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Impervious ratio
Cq
WATER QUALITY Cq1115-1
REFERENCE SECTION1115
January 2008
REFERENCE SECTIONEXEMPT OUTFALLS
INLETS AT INTERSECTIONS
PROFILE
PLAN VIEW
SUMP LOCATION
TREATED
AREA
TREATED
AREA
TREATED
AREA
TREATED
AREA
Contributing Drainage Area 1
Contributing Drainage Area 2
If the contributing drainage areas
to drainage structures #1 or #2 are
less than 0.25 acres, Water Quality
Treatment is not required.
The above example shows areas
that are each less than 0.25 acres.
Treatment is required for the
drainage areas tributary to the
flanking inlets.
PROJECT LIMITS
PROJECT LIMITS
INLET
If the drainage area within the
project limits is less than 0.25
acres, then no Water Quality
Treatment is required.
The hatched areas above indicate
that treatment is not required.
Treatment is required on the through
street.
1
2
1116-1
INLET
AT SUMP
STORM
OUTLET
INLET
AT SUMP
INLETS OR SCUPPERS IN SUMPS
January 2006
1116
Appendix A – Reproducible Forms
Form Subject LD-30 Treated Sanitary Flow Agreement Form LD-33 County Engineer Approval Form LD-34 Storm Sewer Computation Sheet LD-35 Ohio Drainage Design Criteria Form LD-40 Gutter Spread and Inlet Capacity Computation Sheet LD-41 Ditch Computation Sheet LD-42 Culvert Computation Sheet
Form LD-35 Revised January 2006 GENERAL PROJECT INFORMATION
County Route Section
Attach Typical Section) AFFECTED ROADWAYS:
Route
Average Daily Traffic
Rural / Urban
INTERSTATE OR OTHER L/A FACILITIES
ARTERIALS AND COLLECTORS
LOCALS
CLEAR ZONE
All Units are English: PIPE POLICY: The Pipe Policy of _____________________ will be used for this project. (See Section 1002 for additional information) If a policy other than ODOT’s is being used, the following material types are permitted: ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________ (Please attach a copy of the written pipe policy. In lieu of a written policy, documentation of locally funded construction practices may be provided) POST CONSTRUCTION BMP POLICY: The Post Construction BMP Policy of _____________________ will be used for this project.. If a policy other than ODOT’s is being used, the following BMP’s are permitted: ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________ PROJECT SPECIFIC INFORMATION AFFECTING DRAINAGE: ____________________________________________________________________________________________ ____________________________________________________________________________________________ ____________________________________________________________________________________________
Section A. Roadway Culverts (Type A Conduits) 1. DESIGN STORM FREQUENCY (1004.2): a. Mainline _______________ Year
b. Crossroads _______________ Year
2. BANKFULL DESIGN Yes No (Circle yes if at least one culvert has bankfull design) attach a
list of culverts with bankfull designs 3. FLOOD PLAIN CULVERT(S) NEEDED? Yes No (Circle yes if at least one culvert has flood
plain culverts) attach a list of culverts with flood plain culverts 4. DURABILITY SERVICE LIFE _______________ Year attach a list of culverts with their durability
service life if multiple culverts have different frequencies. 5. ABRASIVE SITE? Yes No (Circle yes if at least one culvert has an abrasive site) attach a
list of culverts with their abrasive site assumptions if multiple culverts are different 6. MAXIMUM ALLOWABLE HEADWATER FOR DESIGN STORM (1006.2): a. b. c. 7. METHOD USED TO ESTIMATE DESIGN DISCHARGE (Q) (1003): a. b. 8. SCALE OF TOPOGRAPHIC MAPPING USED TO DELINEATE DRAINAGE AREAS (1101.1): a. b. c. 9. MANNING’S “n” USED FOR (1105.6.5): a. Smooth pipe _______________ b. Corrugated pipe: 2-2/3" x 1/2": Full flow 3" x 1": Full flow 6" x 2": Full flow
Section A. Roadway Culverts - Continued 10. ENTRANCE LOSS COEFFICIENT (ke) (1105.6.6, table 1105-1): a. Corrugated pipe: HW-4 Headwall __________ Full Headwall __________ b. Smooth Concrete pipe HW-4 Headwall __________ Full Headwall __________ d. Box Shape Full Headwall __________ 11. MINIMUM COVER (top of pipe to subgrade) FOR (1008): a. Rigid pipe _______________ b. Flexible pipe _______________ 12. MAXIMUM COVER FOR (1008): a. Rigid pipe _______________ b. Flexible pipe _______________ 13. MAXIMUM ALLOWABLE CULVERT OUTLET VELOCITY (1002.2.2) : a. Bare earth channel _______________ b. Rock channel protection __________________________________________________________ c. Use ____________________ for velocities in excess of 20 f.p.s. 14. HEADWALL TYPE (1106.2): a. b. 15. CONTACT WILL BE MADE WITH COUNTY ENGINEER TO ESTABLISH: a. b. 16. MINIMUM PIPE SIZE (1002.3.1, Figure 1002-1) : a. Freeway or limited access facility _______________ b. Other highways _______________
Section B. Storm Sewers (Type B & C Conduits) 1. DESIGN FREQUENCY (Just Full) _______________ YEAR (1104.4.1) 2. HYDRAULIC GRADIENT SHALL NOT EXCEED (1104.4.2): a. __________ inches below edge of pavement for __________ year frequency storm. b. Pavement catch basin grate or lip of inlet for __________ year frequency storm. c. A point in a depressed pavement sag that would result in an impassible highway for a __________
year frequency storm. d. Other: _______________________________________________________________________ _______________________________________________________________________ e. The above is based on: i. A pipe roughness “n” = __________ for pipe sizes 60" and under and __________ for
larger sizes. ii. _______________________________________________________________________ 3. METHOD USED TO ESTIMATE DESIGN DISCHARGE (Q) (1003): a. b. 4. COEFFICIENT OF RUNOFF “C” FOR (1101.2.3): a. Pavement and paved shoulders _______________ b. Berms and slopes (4:1 and flatter) _______________ c. Berms and slopes (steeper than 4:1) _______________ d. Contributing areas: Residential _______________ Woods _______________ Cultivated _______________ 5. METHOD USED TO DETERMINE TIME TO FIRST CATCH BASIN OR PAVEMENT INLET
(1101.2): a. b. 6. MINIMUM TIME TO (1104.4.4): a. Ditch catch basin __________ minutes b. Pavement inlet or catch basin __________ minutes
Section B. Storm Sewers (Type B & C Conduits) - Continued 7. MINIMUM COVER OVER SEWERS (1104.2.1): a. Rigid pipe: i. Type B conduit (under pavement or paved shoulder) __________ ii. Type C conduit (beyond pavement or paved shoulder) __________ b. Flexible pipe: i. Type B conduit (under pavement or paved shoulder) __________ ii. Type C conduit (beyond pavement or paved shoulder) __________ 8. DESIRABLE MINIMUM VELOCITY FOR DESIGN FLOW _______________ f.p.s (1104.2.1). 9. MAXIMUM LENGTH BETWEEN MANHOLES OR SUITABLE CLEANOUT POINTS (1104.2.2) : a. Under 36"diameter __________ b. 36" - 60" diameter __________ c. Over 60" diameter __________ 10. MINIMUM PIPE SIZE UNDER PAVEMENT (1104.4.6): a. Freeway or limited access facility _______________ b. Other highways _______________ 11. PROCEDURE TO FOLLOW WHEN EXISTING PRIVATE DRAINS ARE CUT BY PROPOSED SEWERS OR DITCHES: _________________________________________________________ _____________________________________________________________________________
Section C. Roadway Ditches 1. METHOD USED TO ESTIMATE DESIGN DISCHARGE (Q) (1003): a. b. 2. DESIGN FREQUENCY TO DETERMINE (1102.3.1 or 1102.4):
ADT >2000: a. Depth of flow determination __________ year
b. Shear Stress determination (for protection and width of protection) __________ year ADT <2000: c. Depth of flow determination __________ year d. Shear Stress determination (for protection and width of protection) __________ year
3. METHOD USED TO DETERMINE TIME OF FLOW TO DITCH (1101.2): _____________________________________________________________________________________ _____________________________________________________________________________________ 4. ALLOWABLE SHEAR STRESS FOR DITCH LINING (1102.3): Permanent Ditch Protection: a. Seed lining __________ psf.
b. Sod or other temporary ditch protection __________ psf. c. Turf Reinforcing Mat (SS836), Type 1 __________ psf. d. Turf Reinforcing Mat (SS836), Type 2 __________ psf. e. Turf Reinforcing Mat (SS836), Type 3 __________ psf. f. RCP, Type B__________psf. g. RCP, Type C__________ psf.
h. RCP, Type D__________ psf.
Temporary Ditch Protection (Item 670):
a. Mat, Type A __________ psf. b. Mat, Type B __________ psf.
c. Mat, Type C __________ psf.
d. Mat, Type E __________ psf. e. Mat, Type F __________ psf.
Section C. Roadway Ditches - Continued
f. Mat, Type G __________ psf.
Tied Concrete Block Mat (Item 601) a. Type 1 __________ psf. b. Type 2 __________ psf. c. Type31 __________ psf.
5. MANNING’S “n” USED FOR (1102.3): a. Seed lining __________ b. Sod, jute, or other temporary linings __________ c. Turf reinforcing mats __________ d. Tied Concrete Block Matting __________ e. Rock channel protection __________ 6. DITCH CONFIGURATION (1102.2): a. ____________________ for roadway, with __________ inch minimum depth b. ____________________ for toe of embankment, with __________ inch minimum depth 7. TYPE OF DITCH CATCH BASIN (1102.3.4): a. 8. MINIMUM LONGITUDINAL SLOPE OF DITCHES IN CUT SECTIONS (1102.1): a. __________ desirable minimum b. __________ absolute minimum 9. METHOD USED TO LOCATE EXISTING FARM TILE CROSSED BY HIGHWAYS? a. b. c. d.
Section C. Roadway Ditches – Continued 10. MINIMUM WIDTH OF DITCH LININGS (1102.3.1) : a. Sod __________ ft. b. Temporary linings __________ ft. c. Turf reinforcing mats __________ ft. 11. DESIGN FREQUENCY DEPTH SHALL NOT EXCEED (1102.3.1):
a.
b.
c.
Section D. Median Ditches 1. DITCH CONFIGURATIONS (1102.3): a. Depressed ____________________ b. Type of barrier ____________________ 2. WIDTH BETWEEN PAVEMENT EDGES _______________ ft. 3. ALLOWABLE SHEAR STRESS FOR DITCH LINING (1102.3): Permanent Ditch Protection: a. Seed lining __________ psf.
i. Sod or other temporary ditch protection __________ psf. j. Turf Reinforcing Mat (SS836), Type 1 __________ psf. k. Turf Reinforcing Mat (SS836), Type 2 __________ psf. l. Turf Reinforcing Mat (SS836), Type 3 __________ psf.
Temporary Ditch Protection (Item 670):
d. Mat, Type A __________ psf. e. Mat, Type B __________ psf.
f. Mat, Type C __________ psf.
g. Mat, Type E __________ psf. h. Mat, Type F __________ psf. i. Mat, Type G __________ psf.
Tied Concrete Block Mat (Item 601) a. Type 1 __________ psf. b. Type 2 __________ psf. c. Type 3 __________ psf.
4. METHOD USED TO ESTIMATE DESIGN DISCHARGE (Q) (1101.2): a. b. 5. CATCH BASIN SPACING WILL BE DETERMINED BY HYDRAULIC ANALYSIS USING
(1102.3.4): a. __________ year frequency and “n” = __________ for velocity b. __________ year frequency and “n” = __________ for depth
c. Controls: i. Design frequency depth shall not exceed: (1) (2) d. Catch basin spacing, depressed median, fill section: Median Width 84' 60' 40' i. Desirable maximum __________________________________________________ ii. Absolute maximum __________________________________________________ 5. TYPE OF MEDIAN CATCH BASIN OR INLET (1102.3.4): a. 7. MINIMUM LONGITUDINAL SLOPE OF DEPRESSED EARTH MEDIAN:
Section E. Drainage for Curbed Pavements 1. CONTROLS FOR THE DETERMINATION OF INLET OR CATCH BASIN SPACING (1103):
a. Design storm frequency __________ year b. Check storm frequency__________ year (for underpasses or depressed roadways where the storm
sewer is the only outlet) c. METHOD USED TO DETERMINE TIME TO FIRST CATCH BASIN OR PAVEMENT
INLET: i. ii.
d. Maximum spread of flow into traveled lane __________ ft. (table 1103-1)
Outside lane width greater than 12 feet ft. Total allowable spread on pavement ft.
e. Maximum depth of flow at curb __________ in . f. Manning’s “n” for: i. Reinforced concrete pavement __________ ii. Asphaltic concrete pavement __________ iii. Paved shoulders __________ 2. TYPE OF INLET OR CATCH BASIN PROPOSED FOR (1103): a. Continuous grades _______________________________________________________________ b. Sags __________________________________________________________________________ 4. INLET LIP OF CURB OPENING INLET WILL BE DEPRESSED __________ INCHES BELOW
NORMAL GUTTER.
a. A local depression of __________ inches will be used to determine spacing of combination grate and curb opening catch basins for a curb pavement section.
b. A local depression of __________ inches will be used to determine spacing of combination grate
and curb opening catch basins for a combination curb and gutter section.
Appendix B – Sample Plan Notes
The Sample plan notes included in this Appendix are the most frequently used. Each note is accompanied by a “Designer Note” in an attempt to give some guidance as to when the note should be used and how to estimate quantities for some of the items where the methods for quantity calculations are not obvious. The following note categories are included:
Category
Letter Prefix
Drainage Notes D Erosion Control Notes E Water Quality Notes W
Appendix B – Sample Plan Notes
April 2010
DRAINAGE (D) ,EROSION CONTROL (E), & WATER QUALITY (W)
NUMBER NAME
D101 Item 604 - Catch Basin Grate
D102 Note Deleted (January 2002)
D103 Item Special - Fill and Plug Existing Conduit
D104 Crossings and Connections to Existing Pipes and Utilities
D105 Pipe Connections to Corrugated Metal Structures
D106 Item 603 - Tunnel Liner Plate Structure
D107 Farm Drains
D108 Item 605 - Aggregate Drains
D109 Spring Drains
D110 Unrecorded Untreated Stormwater Drainage
D111 Unrecorded Treated Stormwater Drainage
D112 Item 603 - Conduit Bored and Jacked
D113 Item 603 - Conduit Under Railroad
D114 Review of Drainage Facilities
D115 Unrecorded Stormwater Drainage
D116 Unrecorded Active Sanitary Sewer Connections
D117 Manholes, Catch Basins and Inlets Removed or Abandoned
D118 Item 511 Wingwalls, Headwalls and Footers for 603 Items
D119 Item Special - Miscellaneous Metal
D120 Note Deleted (April 2010)
D121 Item Special - Pipe Cleanout
D122 Note Deleted (April 2009)
E101 Seeding and Mulching
E102 Sodding
W99 Post Construction Storm Water Treatment
W100 Deleted
W101 Bioretention Cell(s)
W102 Infiltration Trench (or Basin)
W103 Manufactured Water Quality Structure
Appendix B – Sample Plan Notes
April 2010
D101 ITEM 604 - CATCH BASIN GRATE
EXISTING CATCH BASINS SHALL BE MODIFIED BY REPLACING THE EXISTING GRATES WITH BICYCLE SAFE GRATES. QUANTITIES AND LOCATIONS ARE SHOWN IN THE PLANS AND SHALL BE PAID FOR AT THE CONTRACT PRICE FOR ITEM 604, EACH, CATCH BASIN GRATE, TYPE . Designer Note: The above note should be used on projects where existing catch basin grates are not bicycle safe. The size and type of grate to be supplied must be indicated. There may be more than one type and size on a project. If specific locations are not shown in the plan, or additional grates are to be included on a contingency basis, the following should either replace the second sentence in the note or be added to the note: THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR REPLACEMENT OF EXISTING CATCH BASIN GRATES WITH BICYCLE SAFE GRATES: 604, CATCH BASIN GRATE, TYPE , EACH
D103 ITEM SPECIAL - FILL AND PLUG EXISTING CONDUIT THIS ITEM SHALL CONSIST OF THE CONSTRUCTION OF BULKHEADS IN AN EXISTING ____ IN (MM) DIAMETER CONDUIT AND FILLING THE AREA THUS SEALED OFF WITH ITEM 613, SAND OR OTHER MATERIAL APPROVED BY THE ENGINEER. BULKHEADS SHALL BE LOCATED AT THE LIMITS OF THE AREA TO BE FILLED AS INDICATED ON THE PLANS. THE BULKHEADS SHALL CONSIST OF BRICK OR CONCRETE MASONRY WITH A MINIMUM THICKNESS OF 12 INCHES [ 300 MILLIMETERS]. THE FILL MATERIAL SHALL BE PUMPED INTO PLACE, OR PLACED BY OTHER MEANS APPROVED BY THE ENGINEER, SO THAT, AFTER SETTLEMENT, AT LEAST 90 PERCENT OF THE CROSS-SECTIONAL AREA OF THE CONDUIT, FOR ITS ENTIRE LENGTH, SHALL BE FILLED. THE LENGTH OF FILLED AND PLUGGED CONDUIT TO BE PAID FOR SHALL BE THE ACTUAL NUMBER OF FEET [METERS] (MEASURED ALONG THE CENTERLINE OF EACH CONDUIT FROM OUTER FACE TO OUTER FACE OF BULKHEADS) FILLED AND PLUGGED AS DESCRIBED ABOVE. IN LIEU OF FILLING AND PLUGGING THE EXISTING CONDUIT, THE PIPE MAY BE CRUSHED AND BACKFILLED IN ACCORDANCE WITH THE PROVISIONS OF 203, OR IT MAY BE REMOVED. THE LENGTH, MEASURED AS PROVIDED ABOVE, SHALL BE PAID FOR AT THE CONTRACT PRICE PER FOOT [METER] FOR, ITEM SPECIAL, FILL AND PLUG EXISTING CONDUIT. Designer Note: The above note should be used when it is desired to abandon an existing conduit by filling and plugging rather than more conventional methods. If the conduit is in shallow fill, the designer may delete the crush and backfill option specified in the fourth paragraph. Add pay item 202E70000 “202, Special – Fill and plug existing conduit, ___ft (m)” to the plans.
D104 CROSSINGS AND CONNECTIONS TO EXISTING PIPES AND UTILITIES WHERE PLANS PROVIDE FOR A PROPOSED CONDUIT TO BE CONNECTED TO, OR CROSS OVER OR UNDER AN EXISTING SEWER OR UNDERGROUND UTILITY, THE CONTRACTOR
Appendix B – Sample Plan Notes
April 2010
SHALL LOCATE THE EXISTING PIPES OR UTILITIES BOTH AS TO LINE AND GRADE BEFORE STARTING TO LAY THE PROPOSED CONDUIT. IF IT IS DETERMINED THAT THE ELEVATION OF THE EXISTING CONDUIT, OR EXISTING APPURTENANCE TO BE CONNECTED, DIFFERS FROM THE PLAN ELEVATION OR RESULTS IN A CHANGE IN THE PLAN CONDUIT SLOPE, THE ENGINEER SHALL BE NOTIFIED BEFORE STARTING CONSTRUCTION OF ANY PORTION OF THE PROPOSED CONDUIT WHICH WILL BE AFFECTED BY THE VARIANCE IN THE EXISTING ELEVATIONS. IF IT IS DETERMINED THAT THE PROPOSED CONDUIT WILL INTERSECT AN EXISTING SEWER OR UNDERGROUND UTILITY IF CONSTRUCTED AS SHOWN ON THE PLAN, THE ENGINEER SHALL BE NOTIFIED BEFORE STARTING CONSTRUCTION OF ANY PORTION OF THE PROPOSED CONDUIT WHICH WOULD BE AFFECTED BY THE INTERFERENCE WITH AN EXISTING FACILITY. PAYMENT FOR ALL THE OPERATIONS DESCRIBED ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 603 CONDUIT ITEM. Designer Note: The above note is to be used when the designer is unsure of the exact location of a conduit that will require an extension or where the potential for interference between proposed and existing conduits exists.
D105
PIPE CONNECTIONS TO CORRUGATED METAL STRUCTURES CONNECTIONS OF PROPOSED LONGITUDINAL DRAINAGE TO CORRUGATED METAL STRUCTURES SHALL BE MADE BY MEANS OF A SHOP FABRICATED OR FIELD WELDED STUB ON THE STRUCTURE. THE STUB SHALL MEET THE REQUIREMENTS OF 707 AND HAVE A MINIMUM LENGTH OF 2 FEET [0.6 METERS] AND A MINIMUM WALL THICKNESS OF 0.064 INCHES [1.63 MILLIMETERS]. THE LOCATION AND ELEVATION OF THE STUB ARE TO BE CONSIDERED APPROXIMATE AND MAY BE ADJUSTED BY THE ENGINEER TO AVOID CUTTING THROUGH JOINTS IN THE STRUCTURE. THE FIELD WELDED JOINT, IF USED, SHALL BE THOROUGHLY CLEANED AND REGALVANIZED OR OTHERWISE SUITABLY REPAIRED. WELDING SHALL MEET THE REQUIREMENTS OF 513.21. A MASONRY COLLAR, AS PER STANDARD DRAWING DM -1.1, WILL BE REQUIRED TO CONNECT THE LONGITUDINAL DRAINAGE TO THE STUB, WHEN PIPE OTHER THAN CORRUGATED METAL IS PROVIDED FOR THE LONGITUDINAL DRAINAGE. PAYMENT FOR CUTTING INTO THE STRUCTURE AND PROVIDING THE CONNECTION DESCRIBED, SHALL BE INCLUDED IN THE CONTRACT PRICE FOR ITEM 603 OR 522. Designer Note: Use the above note on all projects where connections are proposed to existing corrugated metal conduits.
D106 ITEM 603 - TUNNEL LINER PLATE STRUCTURE IN LIEU OF THE PROVISIONS OF 603.02, MATERIAL FURNISHED FOR THE LINER PLATE STRUCTURE SHALL BE AS MANUFACTURED BY: AMERICAN COMMERCIAL, INC.; COMMERCIAL INTERTECH, CORP.; CONTECH CONSTRUCTION PRODUCTS, INC.; OR AN
Appendix B – Sample Plan Notes
April 2010
APPROVED EQUAL. BASE METAL COMPOSITION, DEPTH AND SPAN OF THE CORRUGATIONS, AND SIZE AND SPACING OF BOLTS AND BOLT HOLES SHALL BE IN ACCORDANCE WITH THE DETAILS OF THE MANUFACTURER. INSTALLATION OF THE STRUCTURE SHALL BE IN ACCORDANCE WITH THE MANUFACTURER’S RECOMMENDATIONS. THE PLATE THICKNESS AND SECTION MODULUS OF THE MATERIAL FURNISHED SHALL NOT BE LESS THAN THAT INDICATED ON THE STRUCTURE DETAILS. GALVANIZING, IF SPECIFIED, SHALL BE IN ACCORDANCE WITH 707.03 AND SHALL BE DONE AFTER CORRUGATING, FORMING, AND PUNCHING THE PLATES AND BOLT HOLES. GRANULAR BEDDING WILL NOT BE REQUIRED. THE COMPLETED STRUCTURE SHALL CONFORM TO THE REQUIREMENTS OF 707. BITUMINOUS COATING, IF SPECIFIED, SHALL MEET THE REQUIREMENTS OF 707.05. Designer Note: If the space between the tunnel excavation and the tunnel liner plate is to be filled with grout, the composition of the grout and spacing of the grout couplings should be shown.
D107
FARM DRAINS ALL FARM DRAINS, WHICH ARE ENCOUNTERED DURING CONSTRUCTION, SHALL BE PROVIDED WITH UNOBSTRUCTED OUTLETS. EXISTING COLLECTORS WHICH ARE LOCATED BELOW THE ROADWAY DITCH ELEVATIONS, AND WHICH CROSS THE ROADWAY, SHALL BE REPLACED WITHIN THE (RIGHT OF WAY)( CONSTRUCTION) LIMITS BY ITEM 603 CONDUIT, TYPE B, ONE COMMERCIAL SIZE LARGER THAN THE EXISTING CONDUIT. EXISTING COLLECTORS AND ISOLATED FARM DRAINS, WHICH ARE ENCOUNTERED ABOVE THE ELEVATION OF ROADWAY DITCHES, SHALL BE OUTLETTED INTO THE ROADWAY DITCH BY 603 TYPE F CONDUIT. THE OPTIMUM OUTLET ELEVATION SHALL BE ONE FOOT [300 MILLIMETERS] ABOVE THE FLOWLINE ELEVATION OF THE DITCH. LATERAL FIELD TILES WHICH CROSS THE ROADWAY SHALL BE INTERCEPTED BY 603, TYPE E CONDUIT, AND CARRIED IN A LONGITUDINAL DIRECTION TO AN ADEQUATE OUTLET OR ROADWAY CROSSING. THE LOCATION, TYPE, SIZE AND GRADE OF REPLACEMENTS SHALL BE DETERMINED BY THE ENGINEER AND PAYMENT SHALL BE MADE ON FINAL MEASUREMENTS. EROSION CONTROL PADS AND ANIMAL GUARDS SHALL BE PROVIDED AT THE OUTLET END OF ALL FARM DRAINS AS PER STANDARD CONSTRUCTION DRAWING DM -1.1, EXCEPT WHEN THEY OUTLET INTO A DRAINAGE STRUCTURE. PAYMENT FOR THE EROSION CONTROL PADS AND ANIMAL GUARDS AND ANY NECESSARY BENDS OR BRANCHES SHALL BE INCLUDED FOR PAYMENT IN THE PERTINENT CONDUIT ITEMS. THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR THE WORK NOTED ABOVE: 603 “ [mm] CONDUIT, TYPE B ________ FT. [METER] 603 “ [mm] CONDUIT, TYPE E ________ FT. [METER] 603 “ [mm] CONDUIT, TYPE F ________ FT. [METER] 601 ROCK CHANNEL PROTECTION TYPE C WITH FILTER ________ CU. YD. [CU. METER] Designer Note: The above note is to be used where excavation may conflict with existing farm drains.
Appendix B – Sample Plan Notes
April 2010
Use of a lateral field interceptor tile located on a temporary easement outside the limited access right of way may be appropriate on limited access facilities.
D108 ITEM 605 - AGGREGATE DRAINS AGGREGATE DRAINS SHALL BE PLACED AT 50 FOOT [10 METER] INTERVALS ON EACH SIDE OF NORMAL CROWNED SECTIONS, STAGGERED SO THAT EACH DRAIN IS 25 FEET [5 METERS] FROM THE ADJACENT DRAIN ON THE OPPOSITE SIDE, AND AT 25 FOOT [5 METER] INTERVALS ON THE LOW SIDE ONLY OF SUPERELEVATED SECTIONS. AN AGGREGATE DRAIN SHALL BE PLACED AT THE LOW POINT OF EACH SAG VERTICAL CURVE. Designer Note: This note should be used on long projects with aggregate drains. On short projects, such as bridge replacements, the station and side for aggregate drain placement should be specified in the plans.
D109 SPRING DRAINS THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN CARRIED TO THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR DRAINING ANY SPRINGS SHOWN IN THE PLAN OR ENCOUNTERED DURING CONSTRUCTION. THE FOLLOWING TYPES OF PIPES MAY BE USED: 707.33, 707.41, 707.42 or 707.45 PERFORATED PER 707.31. SPRING DRAINS SHALL BE CONSTRUCTED AS SHOWN ON STANDARD CONSTRUCTION DRAWING DM-1.1 AND PAID FOR AT THE CONTRACT PRICE FOR: 605, 6" [150 mm] UNCLASSIFIED PIPE UNDERDRAINS FOR SPRINGS ________ FT. [METER] 605, AGGREGATE DRAINS FOR SPRINGS ________ FT. [METER] 604, PRECAST REINFORCED CONCRETE OUTLET ________ EACH Designer Note: This note should be used only where springs are present in the project area and/or the project area is known to have spring activity. In addition to quantities required to drain springs located by field work, estimated contingency quantities should be included for draining springs encountered during construction.
D110
UNRECORDED UNTREATED NON-STORMWATER DRAINAGE FURNISH NO CONTINUANCE FOR ANY UNRECORDED UNTREATED NON-STORMWATER DRAINAGE SUCH AS UNTREATED SEPTIC, UNTREATED WASTEWATER, UNTREATED CURTAIN/GRADIENT DRAINS, AND UNTREATED FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. PLUG ANY UNRECORDED UNTREATED NON-STORMWATER DRAINAGE WITH CLASS C CONCRETE AT THE RIGHT OF WAY LINE. PAYMENT FOR PLUGGING SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 202 OR 203 ITEM. Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional plugging of untreated non-stormwater drainage. The Designer shall make a complete investigation for the presence of untreated non-stormwater drainage. List quantities required for all untreated non-stormwater drainage at the specific locations on the Plan & Profile sheets. All located untreated non-stormwater drainage is required to be plugged with class c concrete at the right -of-way line.
Appendix B – Sample Plan Notes
April 2010
D111 UNRECORDED TREATED NON-STORMWATER DRAINAGE FURNISH A CONTINUANCE FOR ALL UNRECORDED TREATED NON-STORMWATER DRAINAGE, SUCH AS TREATED SEPTIC, TREATED WASTEWATER, TREATED CURTAIN/GRADIENT DRAINS, AND TREATED FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. FURNISH EITHER AN OPEN CONTINUANCE OR AN UNOBSTRUCTED CONTINUANCE BY CONNECTING A CONDUIT THROUGH THE CURB OR INTO A DRAINAGE STRUCTURE. THE LOCATION, TYPE, SIZE AND GRADE OF THE NEEDED CONDUIT TO REPLACE OR EXTEND AN EXISTING DRAIN WILL BE DETERMINED BY THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT. A CONTINUANCE MAY ALSO REQUIRE A NPDES PERMIT FROM THE OHIO ENVIRONMENTAL PROTECTION AGENCY. REPORT ALL CONTINUANCE TO THE LOCAL HEALTH DEPARTMENT. WHERE MAKING A CONNECTION INTO A HIGHWAY DRAINAGE CONDUIT, AN INSPECTION WELL SHALL BE PROVIDED IN ACCORDANCE WITH STANDARD CONSTRUCTION DRAWING DM-3.1. THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER IN MAKING THE ABOVE CONTINUANCE: 603, ______ “ [mm] CONDUIT, TYPE C ________ FT. [METER] 604, INSPECTION WELL ________ EACH Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of treated non-stormwater drainage. The Designer shall make a complete investigation for the presence of treated non-stormwater drainage. List quantities required for all treated non-stormwater drainage at the specific locations on the Plan & Profile sheets. All located treated non-stormwater drainage is required to have a right of way use permit. If any such located treated non-stormwater drainage do not have a right of way use permit then notice of such is required to be sent to the appropriate parities. All treated non-stormwater drainage may also require a NPDES permit from the Ohio Environmental Protection Agency. Report all continuance to the local health department.
D112 ITEM 603 - CONDUIT BORED OR JACKED WHERE IT IS SPECIFIED THAT A CONDUIT BE INSTALLED BY THE METHOD OF BORING OR JACKING, NO TRENCH EXCAVATION SHALL BE CLOSER THAN _____ FEET [METERS] TO THE (EDGE OF PAVEMENT) (NEAREST RAIL). PROVIDE A 0.50 INCH (12.7 MM) UNGALVANIZED CASING PIPE CONFORMING TO 748.06 THAT HAS JOINTS WITH A CIRCUMFERENCIAL FULLY PENETRATING B-U4B WELD THAT IS PERFORMED BY AN ODOT APPROVED FIELD WELDER. THE INSTALLED CASING PIPE IS THE STORM WATER CONVEYANCE CARRIER UNLESS OTHERWISE SPECIFIED IN THE PLANS. HYDROSTATIC TESTING IS NOT REQUIRED FOR THE CASING PIPE. Designer Note: The pay item in the General Summary shall read, 603 Conduit, Bored or Jacked, “ [mm], Type , Ft. [meters]. Where a conduit is installed by this method under a railroad, the designer should coordinate with the Rail Company to determine the allowable distance from the nearest rail and add note D113 to the plans. Specify a concrete masonry collar between the casing pipe and adjacent conduit material if the casing pipe is used as the final carrier pipe.
Appendix B – Sample Plan Notes
April 2010
D113 ITEM 603 – CONDUIT UNDER RAILROAD THE STATE SHALL PAY TO THE RAIL COMPANY ALL COSTS FOR WATCHMEN OR FLAGGERS DEEMED NECESSARY BY THE RAIL COMPANY, OR OCCASIONED BY THE OPERATIONS OF THE CONTRACTOR, OR ANY SUB -CONTRACTOR, IN CARRYING FORWARD THE INSTALLATION OF PIPE OR CONDUIT UNDER THE RAILROAD PER THE PLAN. THE COSTS FOR WATCHMEN OR FLAGGERS REQUIRED BY AN ALTERNATE METHOD OF INSTALLATION SHALL BE PAID TO THE RAIL COMPANY BY THE CONTRACTOR. THE COSTS FOR WATCHMEN OR FLA GGERS OCCASIONED BY THE NEGLIGENCE OF THE CONTRACTOR, OR ANY SUB-CONTRACTOR, IN CONNECTION WITH THE INSTALLATION OF THE PIPE OR CONDUIT SHALL BE PAID BY THE CONTRACTOR. TRACK SUPPORTS REQUIRED BY THE RAIL COMPANY IN CONNECTION WITH THE INSTALLATION OF THE PIPE OR CONDUIT PER THE PLAN SHALL BE INCLUDED IN THE COMPANY FORCE ACCOUNT WORK AND PAID BY THE STATE. THE COST OF ANY TRACK SUPPORTS REQUIRED BY AN ALTERNATE METHOD OF INSTALLATION OF THE PIPE OR CONDUIT SHALL BE SHALL BE PAID TO THE RAIL COMPANY BY THE CONTRACTOR. THE CONTRACTOR SHALL SECURE APPROVAL OF HIS OPERATIONS FROM THE STATE AND THE RAIL COMPANY. THE RAIL COMPANY WILL PERFORM AN ENGINEERING REVIEW OF METHODS OF OPERATIONS AND ENGINEERING SUPERVISION OF CONSTRUCITON WITHOUT COST TO THE CONTRACTOR. PRIOR TO BIDDING, THE CONTRACTOR SHALL COORDINATE WITH THE RAIL COMPANY TO AGREE UPON THE REQUIREMENTS OF WATCHMEN AND FLAGGERS TO PROTECT RAILROAD TRAFFIC DURING THE CONTRACTOR’S OPERATIONS. THE CONTRACTOR SHALL EXECUTE A BOND IN FAVOR OF BOTH THE STATE AND THE COMPANY AS REQUIRED BY SECTION 5525.16 OF THE REVISED CODE OF OHIO. THE CONTRACTOR SHALL CO-OPERATE WITH THE RAILROAD OFFICIALS CONCERNING WORK ADJACENT TO RAILROAD TRACKS, IN ORDER TO AVOID DELAY TO, OR INTERFERENCE WITH RAILROAD TRAFFIC, AND SHALL NOTIFY THE COMPANY ______ HOURS IN ADVANCE OF CONSTRUCTION OPERATIONS. Designer Note: Provide this note when placing pipe culverts, sewers, or water lines under railroads. Through coordination with the railroad complete the ____hours that the railroad would like to be notified by.
D114
REVIEW OF DRAINAGE FACILITIES BEFORE ANY WORK IS STARTED ON THE PROJECT AND AGAIN BEFORE FINAL ACCEPTANCE BY THE STATE, REPRESENTATIVES OF THE STATE AND THE CONTRACTOR, ALONG WITH LOCAL REPRESENTATIVES, SHALL MAKE AN INSPECTION OF ALL EXISTING SEWERS WHICH ARE TO REMAIN IN SERVICE AND WHICH MAY BE AFFECTED BY THE WORK. THE CONDITION OF THE EXISTING CONDUITS AND THEIR APPURTENANCE SHALL BE DETERMINED FROM FIELD OBSERVATIONS. RECORDS OF THE INSPECTION SHALL BE KEPT IN WRITING BY THE STATE. ALL NEW CONDUITS, INLETS, CATCH BASINS, AND MANHOLES CONSTRUCTED AS A PART OF THE PROJECT SHALL BE FREE OF ALL FOREIGN MATTER AND IN A CLEAN CONDITION BEFORE THE PROJECT WILL BE ACCEPTED BY THE STATE. ALL EXISTING SEWERS INSPECTED INITIALLY BY THE ABOVE MENTIONED PARTIES SHALL
Appendix B – Sample Plan Notes
April 2010
BE MAINTAINED AND LEFT IN A CONDITION REASONABLY COMPARABLE TO THAT DETERMINED BY THE ORIGINAL INSPECTION. ANY CHANGE IN THE CONDITION RESULTING FROM THE CONTRACTOR’S OPERATIONS SHALL BE CORRECTED BY THE CONTRACTOR TO THE SATISFACTION OF THE ENGINEER. PAYMENT FOR ALL OPERATIONS DESCRIBED ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 603 CONDUIT ITEMS. Designer Note: This note is to be used on projects where existing drainage facilities are to remain in service.
D115
UNRECORDED STORM WATER DRAINAGE FURNISH A CONTINUANCE FOR ALL UNRECORDED STORM WATER DRAINAGE, SUCH AS ROOF DRAINS, FOOTER DRAINS, OR YARD DRAINS, DISTURBED BY THE WORK. FURNISH EITHER AN OPEN CONTINUANCE OR AN UNOBSTRUCTED CONTINUANCE BY CONNECTING A CONDUIT THROUGH THE CURB OR INTO A DRAINAGE STRUCTURE. THE LOCATION, TYPE, SIZE AND GRADE OF THE NEEDED CONDUIT TO REPLACE OR EXTEND AN EXISTING DRAIN WILL BE DETERMINED BY THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT. THE FOLLOWING CONDUIT TYPES MAY BE USED: 707.33, 707.41 NON-PERFORATED, 707.42, 707.43, 707.45, 707.46, 707.47, 707.51, 707.52 SDR35. THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR THE WORK NOTED ABOVE: 603, ______ “ [mm] CONDUIT, TYPE B, FOR DRAINAGE CONNECTION ________ FT. [METER] 603, ______ “ [mm] CONDUIT, TYPE C, FOR DRAINAGE CONNECTION ________ FT. [METER] 603, ______ “ [mm] CONDUIT, TYPE E, FOR DRAINAGE CONNECTION ________ FT. [METER] 603, ______“ [mm] CONDUIT, TYPE F, FOR DRAINAGE CONNECTION ________ FT. [METER]
Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of storm water drainage from residential or commercial property. The designer shall make a complete investigation for the presence of existing storm water drainage from residential and commercial property. List quantities required for all located storm water drainage from residential and commercial property at the specific locations on the Plan & Profile sheets. All located storm water drainage from residential or commercial property is required to have a right of way use permit. If any such located storm water drainage from residential or commercial property do not have a right of way use permit then notice of such is required to be sent to the appropriate parities. Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional residential and commercial connections. The designer shall make a complete investigation for the presence of existing residential and commercial drainage connections and quantities should be listed at the specific locations on the Plan & Profile sheets.
Appendix B – Sample Plan Notes
April 2010
D116 UNRECORDED ACTIVE SANITARY SEWER CONNECTIONS FURNISH A CONTINUANCE FOR ALL UNRECORDED ACTIVE SANITARY SEWER CONNECTIONS SUCH AS SANITARY, WASTEWATER, CURTAIN/GRADIENT DRAINS, AND FOUNDATION FLOOR DRAINS DISTURBED BY THE WORK. FURNISH AN UNOBSTRUCTED CONTINUANCE OF THE UNRECORDED ACTIVE SANITARY SEWER CONNECTIONS TO THE SATISFACTION OF THE ENGINEER. ALL SUCH CONTINUANCE REQUIRES A RIGHT OF WAY USE PERMIT. ALL SANITARY AND SANITARY WASTEWATER CONTINUANCE MAY ALSO REQUIRE A NPDES PERMIT FROM THE OHIO ENVIRONMENTAL PROTECTION AGENCY. REPORT ALL CONTINUANCE TO THE LOCAL HEALTH DEPARTMENT. THE FOLLOWING CONDUIT TYPES MAY BE USED: 707.42, 707.43, 707.44, 707.45, 707.46, 707.47, 707.51, 707.52 SDR35, 706.01, 706.02, OR 706.08 WITH JOINTS AS PER 706.11 OR 706.12. THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER FOR THE WORK NOTED ABOVE: 603, ______ “ [mm] CONDUIT, TYPE B, FOR SANITARY ______ FT. [METER] 603, ______ “ [mm] CONDUIT, TYPE C, FOR SANITARY ______ FT. [METER] Designer Note: This note is to be used only if there is a possibility that during construction there may be a need for additional continuance of active sanitary sewer connections. The Designer shall make a complete investigation for the presence of active sanitary sewer connections. List quantities required for all active sanitary sewer connections at the specific locations on the Plan & Profile sheets. All located active sanitary sewer connections is required to have a right of way use permit. If any such located active sanitary sewer connections do not have a right of way use permit then notice of such is required to be sent to the appropriate parities. All sanitary and sanitary wastewater active sanitary sewer connections may also require a NPDES permit from the Ohio Environmental Protection Agency. Report all continuance to the local health department.
D117 MANHOLES, CATCH BASINS AND INLETS REMOVED OR ABANDONED ALL CASTINGS SHALL BE CAREFULLY REMOVED AND STORED WITHIN THE RIGHT OF WAY FOR SALVAGE BY (STATE) (CITY) (VILLAGE) (COUNTY) FORCES. PAYMENT FOR ALL OF THE ABOVE SHALL BE INCLUDED IN THE CONTRACT PRICE FOR THE PERTINENT 202 ITEM. Designer Note: This note shall only be used where it has been determined that the owner desires to retain the existing castings.
D118
ITEM 511 WINGWALLS, HEADWALLS, AND FOOTERS FOR 603 ITEMS FOR ITEMS 706.05, 706.051, 706.052 AND 706.053 WITH A CAST-IN-PLACE WINGWALL, HEADWALL, OR FOOTER, A PRECAST ALTERNATIVE MAY BE FURNISHED PER 602.03. THE PRECAST ALTERNATIVE WILL MEET THE CAST-IN-PLACE STRUCTURAL DESIGN LOADINGS, DESIGN HEIGHT, AND DESIGN LENGTH DIMENSIONS.
Appendix B – Sample Plan Notes
April 2010
FULL COMPENSATION FOR THE PRECAST WINGWALL, HEADWALL, OR FOOTER IS THE NUMBER OF CUBIC YARDS (CUBIC METERS) OF ITEM 511 OR SUPPLEMENTAL SPECIFICATION 898, AND POUNDS (KILOGRAMS) OF ITEM 509 FOR THE CORRESPONDING CAST-IN-PLACE STRUCTURE. Design Note: Include this note on all plans that have item 603 or SS802 three-sided flat top, arch top, arches or box culverts that have an item 511 or SS898 cast-in-place wingwall, headwall, or footer.
D119
ITEM SPECIAL- MISCELLANEOUS METAL EXISTING CASTINGS MAY PROVE TO BE UNSUITABLE FOR REUSE, AS DETERMINED BY THE ENGINEER. IT SHALL BE THE CONTRACTOR’S RESPONSIBILITY TO PROVIDE THE CASTINGS OF THE REQUIRED TYPE, SIZE AND STRENGTH (HEAVY OR LIGHT DUTY) FOR THE PARTICULAR STRUCTURE IN QUESTION. ALL MATERIAL SHALL MEET ITEM 604 OF THE SPECIFICATIONS AND SHALL HAVE THE PRIOR APPROVAL OF THE ENGINEER. THE FOLLOWING ESTIMATED QUANTITY HAS BEEN CARRIED TO THE GENERAL SUMMARY FOR USE AS DIRECTED BY THE ENGINEER. SPECIAL, MISCELLANEOUS METAL _____ POUNDS [KILOGRAMS] THE CONTRACTOR IS CAUTIONED TO USE EXTREME CARE IN THE REMOVAL, STORAGE AND REPLACEMENT OF ALL EXISTING CASTINGS. CASTINGS DAMAGED BY THE NEGLIGENCE OF THE CONTRACTOR, AS DETERMINED BY THE ENGINEER, SHALL BE REPLACED WITH THE PROPER NEW CASTINGS AT THE EXPENSE OF THE CONTRACTOR. Designer Note: Use this note if existing castings are to be reused and which may be unsuitable.
D121
ITEM SPECIAL - PIPE CLEANOUT THIS WORK SHALL CONSIST OF REMOVING SEDIMENT AND DEBRIS FROM THE EXISTING DRAINAGE CONDUITS SPECIFIED IN THE PLANS. ALL MATERIAL REMOVED SHALL BE DISPOSED OF AS PER 105.16 AND 105.17. ALL SEWERS SHALL BE CLEANED OUT TO THE SATISFACTION OF THE ENGINEER. CLEANOUT OF THE PIPE SHALL BE PAID FOR AT THE UNIT PRICE BID FOR ITEM SPECIAL - PIPE CLEANOUT. THIS PRICE SHALL INCLUDE THE COST FOR MATERIAL, EQUIPMENT, LABOR, AND ALL INCIDENTALS REQUIRED TO COMPLETE THE CLEANOUT. THE FOLLOWING ESTIMATED QUANTITIES HAVE BEEN INCLUDED IN THE GENERAL SUMMARY FOR THE ABOVE NOTED WORK: SPECIAL, PIPE CLEANOUT ________ FT. [METER] Designer Note: This item may not be eligible for federal participation.
Appendix B – Sample Plan Notes
April 2010
E101
SEEDING AND MULCHING THE FOLLOWING QUANTITIES ARE PROVIDED TO PROMOTE GROWTH AND CARE OF PERMANENT SEEDED AREAS: 659, SOIL ANALYSIS TEST ____ EACH 659, TOPSOIL ____ CU. YD. (CU. METER) 659, SEEDING AND MULCHING ____ SQ. YD. (SQ. METER) 659, REPAIR SEEDING AND MULCHING ____ SQ. YD. (SQ. METER) 659, INTER-SEEDING ____ SQ. YD. (SQ. METER) 659, COMMERCIAL FERTILIZER ____ TON (KILOGRAM) 659, LIME ____ ACRES (HECTARES) 659, WATER ____ M. GAL. (CU. METER) 659, MOWING ____ M. SQ. FT. (SQ. METER) SEEDING AND MULCHING SHALL BE APPLIED TO ALL AREAS OF EXPOSED SOIL BETWEEN THE RIGHT-OF-WAY LINES, AND WITHIN THE CONSTRUCTION LIMITS FOR AREAS OUTSIDE THE RIGHT-OF-WAY LINES COVERED BY WORK AGREEMENT OR SLOPE EASEMENT. QUANTITY CALCULATIONS FOR SEEDING AND MULCHING ARE BASED ON THESE LIMITS. Designer Note: The above quantities should be used on all projects that require grading work. The following is a basic guideline for estimating quantities for the above items. These quantities may be omitted from the note if they are itemized elsewhere in the plan. Calculations for all items should be shown in the plans. 659, Soil Analysis Test (Each) Soil Analysis Tests are used to field adjust the rate of Lime based on soil conditions. A. Soil Analysis Test is not specified.
1. The standard rate for Lime will be used without adjustment.
B. Soil Analysis Test is specified. If specified, minimum of two tests.
1. If no Topsoil to be placed - One test per 10 Acres (one test per 48400 Sq. Yd.)[one test per 40000 Sq. Meters] of permanent seeded area and sodded area.
2. If placing Topsoil - One test per 10000 Cu. Yds. [7600 Cu. Meters] of Topsoil.
659, Topsoil (Cu. Yd.)[Cu. Meter] 111 Cu. Yds. per 1000 Sq. Yd. [0.10 Cu. Meter per Sq. Meter] of permanent seeded area. Topsoil is optional. However, it is recommended, especially for projects involving A4 silty materials, granular embankment or granular materials due to severe erosion problems.
659, Seeding and Mulching (Sq. Yd.)[Sq. Meter]
Appendix B – Sample Plan Notes
April 2010
This quantity is usually calculated by the end width method using the cross sections. On short projects, seeding quantities may be determined by other methods. For example, the area for seeding may be estimated by calculating an area per Plan & Profile sheet determined by multiplying an average width (based on construction limits or right-of -way lines) by the distance on each sheet, and then deducting for paved surface areas. A deduction should be taken for 660 and 670 items. 659, Repair Seeding and Mulching (Sq. Yd.) [Sq. Meter] 5 % of the permanent seeding and mulching area. 659, Inter-seeding (Sq. Yd.)[Sq. Meter] 5% of the permanent seeding and mulching area.
659, Commercial Fertilizer (Ton)[Kilogram]
30 pounds per 1000 Sq. Ft. ( one Ton per 7410 Sq. Yd.)[0.15 Kg/Sq. Meter] of permanent seeded area. This rate includes 20 pounds per 1000 Sq. Ft. [0.10 kg per Sq. Meter] for the first application and 10 pounds per 1000 Sq. Ft. [0.05 kg per Sq. meter] for the second application. If Inter-seeding is provided, use an additional 20 pounds per 1000 Sq. Ft. of commercial fertilizer for the Inter-seeding area. 659 Lime (Acre)[Hectare] Apply over permanent seeded area. 659, Water (M. Gal.)[Cu. Meter] Two applications each at 300 Gallons per 1000 Sq. Ft. (0.0027 M Gallons per Sq. Yd.) [12.2 Cu. Meters per 1000 Sq. Meters] of permanent seeded area. The above rate is for a single application. If Inter-seeding is provided, use an additional 300 Gallons per 1000 Sq. Ft. of water for the Inter-seeded area. 659, Mowing (M. Sq. Ft.)[Sq. Meter]
25 % of the permanent seeded area for projects expected to last more than one construction season.
E102
SODDING THE FOLLOWING QUANTITIES ARE PROVIDED TO PROMOTE GROWTH AND CARE OF PERMANENT SODDED AREAS. 659, SOIL ANALYSIS TEST ____ EACH 659, TOPSOIL ____ CU. YD. (CU. METER) 659, COMMERCIAL FERTILIZER ____ TON (KILOGRAM) 659, LIME ____ ACRE (HECTARE) 659, WATER ____ M. GAL. (CU. METER) 660, SODDING, UNSTAKED, STAKED, REINFORCED ____ SQ. YD. (SQ. METER) Designer Note: The above quantities should be used on all projects that have pay item(s) for permanent sodding. The following is a basic guideline for estimating quantities for the above items. These quantities may be omitted from the note if they are itemized elsewhere in the plan. Calculations for all items should be shown in the plans.
Appendix B – Sample Plan Notes
April 2010
659, Soil Analysis Test (Each) Soil Analysis Tests are used to field adjust the rate of Lime based on soil conditions. C. Soil Analysis Test is not specified.
1. The standard rate for Lime will be used without adjustment.
D. Soil Analysis Test is specified. If specified, minimum of two tests.
1. If no Topsoil to be placed - One test per 10 Acres (one test per 48400 Sq. Yd.)[one test per 40000 Sq. Meters] of permanent sodded area.
2. If placing Topsoil - One test per 10000 Cu. Yds. [7600 Cu. Meters] of Topsoil.
659, Topsoil (Cu. Yd.)[Cu. Meter] 111 Cu. Yds. per 1000 Sq. Yd. [0.10 Cu. Meter per Sq. Meter] of permanent sodded area. Topsoil is optional. However, it is recommended, especially for projects involving A4 silty materials, granular embankment or granular materials due to severe erosion problems. 659, Commercial Fertilizer (Ton)[Kilogram] 30 pounds per 1000 Sq. Ft. ( one Ton per 7410 Sq. Yd.)[0.15 Kg/Sq. Meter] of permanent sodded area. This rate includes 20 pounds per 1000 Sq. Ft. [0.10 kg per Sq. Meter] for the first application and 10 pounds per 1000 Sq. Ft. [0.05 kg per Sq. meter] for the second application. 659, Lime (Acre)[Hectare] Apply over permanent sodded area. 659, Water (M. Gal.)[Cu. Meter] 1 application every 7 days for an additional 2 months beyond the requirements of 660.09. The rate shall be 300 gallons per 1000 Sq. Ft. (0.0027 M. Gallons per Sq. Yd.) [12.2 Cu. Meters per 1000 Sq. Meters] of permanent sodded area. 660, Sodding (Sq. Yd.)[Sq. Meter] This is the actual number of Sq. Yds. [Sq. Meters] of permanent sodded area.
Appendix B – Sample Plan Notes
April 2010
W99 POST CONSTRUCTION STORM WATER TREATMENT THIS PLAN UTILIZES STRUCTURAL BEST MANAGEMENT PRACTICES (BMP’S) FOR POST CONSTRUCTION STORM WATER TREATMENT. Designer Note: This plan note shall be used on all projects that have post construction storm water management BMP’s. The note shall be followed by the below notes if applicable.
W101 BIORETENTION CELL(S)
CONSTRUCT THE BIORETENTION CELL(S) AFTER ALL CONTRIBUTING DRAINAGE AREAS ARE STABILIZED AS SHOWN ON THE CONTRACT PLANS AND TO THE SATISFACTION OF THE ENGINEER. DO NOT USE THE COMPLETED BIORETENTION CELL(S) AS TEMPORARY SEDIMENT CONTROL FACILITIES DURING CONSTRUCTION. DO NOT OPERATE HEAVY EQUIPMENT WITHIN THE PERIMETER OF A BIORETENTION FACILITY DURING EXCAVATION, UNDERDRAIN PLACEMENT, BACKFILLING, PLANTING, OR MULCHING OF THE FACILITY. USE ALL SUITABLE EXCAVATED MATERIAL IN THE WORK. ALTERNATIVELY, LEGALLY USE, RECYCLE, OR DISPOSE OF ALL EXCAVATED MATERIALS ACCORDING TO 105.16 AND 105.17. EXCAVATE THE BIORETE NTION CELL(S) TO THE DIMENSIONS, SIDE SLOPES, AND ELEVATIONS SHOWN ON THE CONTRACT PLANS. MINIMIZE THE COMPACTION OF THE BOTTOM OF THE BIORETENTION FACILITY BY THE METHOD OF EXCAVATION. EMBANKMENT WILL BE MEASURED AND PAID AS ITEM 203, EMBANKMENT, USING NATURAL SOIL, 703.16.A. THE BIORETENTION SOIL SHALL BE A UNIFORM MIX THAT IS FREE OF STONES, STUMPS, ROOTS, OR ANY OTHER OBJECT THAT IS LARGER THAN TWO INCHES. THE SOIL MAY CONSIST OF EXISTING SOIL, FURNISHED SOIL, OR A COMBINATION OF BOTH PROVIDED THAT IT MEETS THE FOLLOWING REQUIREMENTS: THOROUGHLY MIX THE BIORETENTION SOIL PRIOR TO PLACEMENT. TEST AND ADJUST THE PH AS PER CMS 659.02.B. ALL SAND USED SHALL MEET CMS 203.02.H, NATURAL GRANULAR MATERIALS. PLACE THE SOIL IN 12 INCH LIFTS AND CONSOLIDATE BY WATERING UNTIL SATURATED. CONSTRUCT THE UNDERDRAIN SYSTEM AS PER CMS 605. PLACE THE GRANULAR BACKFILL MATERIAL TO THE INVERT OF THE BIORETENTION SOIL. ENSURE A MINIMUM OF 2 INCHES OF GRANULAR COVER OVER THE UNDERDRAIN PRIOR TO PLACEMENT OF THE BIORETENTION SOIL. PLACE OBSERVATION WELLS AND CLEANOUTS WHERE SHOWN IN THE PLANS. CONNECT THE WELLS/CLEANOUTS TO THE PERFORATED UNDERDRAIN WITH THE APPROPRIATE MANUFACTURED CONNECTIONS. THE WELLS/CLEANOUTS SHALL EXTEND 6 INCHES ABOVE THE TOP ELEVATION OF THE BIORETENTION FACILITY MULCH. CAP THE WELLS/CLEANOUTS
PH RANGE: 5.2-7.0
COMPOSITION BY VOLUME
4 PARTS SAND – CMS FINE AGGREGATE AS PER 703
2 PARTS COMPOST – CMS 659.06
2 PARTS TOPSOIL – CMS 659.05
Appendix B – Sample Plan Notes
April 2010
WITH A THREADED SCREW CAP. CAP THE ENDS OF UNDERDRAIN PIPES NOT TERMINATING IN AN OBSERVATION WELL/CLEANOUT OR CONNECTED TO OTHER CONDUITS. PLACE TREES, SHRUBS, AND OTHER PLANT MATE RIALS SPECIFIED FOR BIORETENTION FACILITIES AS SPECIFIED IN THE PLANS. PLANT MATERIALS WILL BE MEASURED AND PAID FOR PER CMS ITEM 661. APPLY NO PESTICIDES, HERBICIDES, AND FERTILIZERS DURING PLANTING, ESTABLISHMENT, OR MAINTENANCE UNDER ANY CIRCUMSTANCES. BIORETENTION CELLS WILL BE PAID FOR AS ITEM SPECIAL, BIORETENTION CELL AT THE CONTRACT BID LUMP SUM PRICE. THE PAYMENT WILL BE FULL COMPENSATION FOR ALL APPLICABLE INCIDENTA LS NECESSARY TO SATISFACTORILY COMPLETE THE WORK. Designer Note: This plan note shall be used on all projects that have bioretention cell(s) identified in the plan. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, using natural soils, 703.16.A.
W102 INFILTRATION TRENCH (OR BASIN)
THIS PLAN UTILIZES INFILTRATION FOR POST CONS TRUCTION STORM WATER TREATMENT. CONSTRUCT THE COMPLE TED INFILTRATION TRE NCH(ES) (AND OR BASIN(S)) AFTER ALL CONTRIBUTING DRAINAGE AREAS ARE STABILIZED AS SHOWN IN THE CONTRACT PLANS AND TO THE SATISFACTION OF THE ENGINEER. DO NOT USE INFILTRATION DEVICES AS TEMPORARY SEDIMENT CONTROL FACILITIES DURING CONSTRUCTION. DO NOT OPERATE HEAVY EQUIPMENT WITHIN THE PERIMETER OF AN INFILTRATION DEVICE DURING EXCAVATION OR BACKFILLING OF THE FACILITY. Designer Note: This plan note shall be used on all projects that have infiltration trenches and or basins identified in the plan. Embankment work to create the impoundment will be constructed and paid for as Item 203 Embankment, using natural soils, 703.16.A.
W103 MANUFACTURED WATER QUALITY STRUCTURE
THIS PLAN UTILIZES MANUFACTURED WATER QUALITY STRUCTURES FOR WATER QUALITY TREATMENT. AREAS HAVE BEEN SHOWN IN THE PLANS FOR PLACEMENT OF AN OFF-LINE SYSTEM. PAYMENT FOR THESE DEVICES SHALL BE MADE AT THE CONTRACT UNIT PRICE FOR ITEM 895, MANUFACTURED WATER QUALITY STRUCTURE, TYPE ____. Designer Note: This plan note shall be used on all projects that have manufactured water quality structures identified in the plan. If more than one manufactured water quality structure is provided in the plans, a table shall be provided to indicate the location and type of each structure used. Supplemental specification 895 outlines the different types of structures (1-4). Manufactured systems may not be used without approval of the Hydraulics Section through a feasibility study. Contact the Hydraulics Section for an area dimension that shall be shown in the plan.
