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The Springs Specific Plan LAND USE AND CIRCULATION ALTERNATIVES REPORT APPENDIX B Utility Infrastructure Needs Report
TheSpringsSpecificPlanLAND USE AND CIRCULATION
ALTERNATIVES REPORT
APPENDIXB
UtilityInfrastructureNeedsReport
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Table of Contents
Section 1 Introduction
1.0 Introduction 1‐1 1.1 Existing Conditions 1‐2 1.2 General Overview of Infrastructure Needs 1‐3 1.3 Special Concerns Related to Infrastructure Improvements 1‐3
Section 2 Water Infrastructure
2.0 Water Distribution Collection Facilities 2‐1 2.1 Analysis 2‐2 2.2 Conclusion 2‐9
Section 3 Sanitary Sewer Infrastructure
3.0 Sanitary Sewer Collection Facilities 3‐1 3.1 Analysis 3‐2 3.3 Conclusion 3‐9
Section 4 Storm Drain Infrastructure
4.0 Storm Drain Infrastructure and Collection Facilities 4‐1
4.1 Analysis 4‐3
4.2 Conclusion 4‐5
Section 5 Dry Utility Infrastructure and Facilities
5.0 Dry Utility Infrastructure and Facilities 5‐1 5.1 Analysis 5‐2 5.2 Conclusion
Appendix A
Tables Figures
Appendix B
Attachments
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1.0 ‐ Introduction
EBA Engineering (EBA) has prepared this technical review to provide existing utility infrastructure
information for use in developing The Springs Specific Plan. The intent of this document is to analyze
the land use density increases proposed by The Springs Specific Plan Alternatives in order to evaluate
the infrastructure needs for water distribution, sewer collection, and storm water conveyance. In
addition, a cursory survey of available dry utilities including electric, gas, and telecommunications has
been completed. This work will provide recommendations on what utility infrastructure should be
upgraded, replaced, or extended to accommodate future buildout.
The Springs Specific Plan area consists of approximately 179 acres located in the County of Sonoma. The
area is located just northwest of City of Sonoma and outs Urban Growth Boundary, Sphere of Influence,
and Urban Services Area. The information contained within this report is based on available information
obtained from various agencies and municipalities servicing the area. These areas include Valley of the
Moon Water District (VOMWD), the Sonoma Valley Sanitation District (SVSD), Sonoma County Water
Agency, the County of Sonoma, and the Sonoma County Department of Transportation and Public
Works (SCDTPW).
Land Use and Circulation Alternative Map 1 (Alternative 1) embodies the buildout of the Springs Specific
Plan area at the highest land use densities. As the area is mostly developed, this projection assumes
significant changes in use and complete redevelopment of many portions of the Specific Plan area.
Land Use and Circulation Alternative Map 2 (Alternative 2) represents the buildout of the Springs
Specific Plan area at moderate land use density increases. Again, as the area is mostly developed, this
projection assumes major changes in use and complete redevelopment of many portions of the Specific
Plan area.
Land Use and Circulation Alternative Map 3 (Alternative 3) represents the buildout of the Springs
Specific Plan area at the current land use zoning designations. Given that the area is mostly developed,
this projection generally accounts for infill development and yields small increase in dwellings units,
population, and non‐residential square footages.
Disclaimer
Modeling of the existing or proposed systems is beyond the scope of this report; further study,
calculations, and modeling are necessary to determine the actual extent of infrastructure changes and
should be conducted as part of incremental development and buildout of the area.
Dry utility information is based on mapping information provided by each supplier and field
reconnaissance. This information is approximate and should be individually verified before any
development proceeds.
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1.1 ‐ Existing Conditions
Existing Utility Infrastructure Location
EBA worked with the VOMWD, SVCSD, SCWA, SCDTPW, PG&E and Comcast to review the existing utility
infrastructure within the limits of the Springs Specific Plan boundary; which included gathering base
mapping, existing improvement plans, and existing master utility plans.
EBA prepared the following tables, found in Appendix A, based upon the complied information:
Table 1‐1 Existing Wet Utility Infrastructure Availability Summary
Table 1‐2 Existing Water System Infrastructure Summary
Table 1‐3 Existing Sewer System Infrastructure Summary
Table 1‐4 Existing Storm Drain Infrastructure Summary
Table 1‐1, Existing Wet Utility Infrastructure Summary, provides a summary of the availability of water,
sewer, and storm drain for each road located within the Springs Specific Plan boundary. Table 1‐2, Existing
Water System Infrastructure Summary, provides a summary of the size, type, and available pressures of
each water main for each road located within the Springs Specific Plans boundary. Table 1‐3, Existing
Sewer System Infrastructure Summary, provides a summary of the size, type, and flows of each sewer
main for each road located within the Springs Specific Plans boundary. Table 1‐4, Existing Storm Drain
System Infrastructure Summary, provides a summary of the size and type of each storm drain for each
road located within the Springs Specific Plans boundary.
To further clarify the existing water, sewer, and storm drain infrastructure; base maps were prepared for
each of these utilities and over laid onto a map with the Springs Specific Plan boundary outlined.
EBA prepared the following figures, found in Appendix A, based upon the complied information:
Figure 1‐1 Water System Base Map April 2016
Figure 1‐2 Sanitary Sewer Base Map April 2016
Figure 1‐3 Storm Drain Base Map April 2016
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1.2 ‐ General Overview of Infrastructure Needs
Based on the information reviewed, there appears to be wet utility infrastructure available to serve the
area within the Springs Specific Plan boundary. Water and sanitary sewer infrastructure is available
within streets and/or easements adjacent to all parcels but it should be noted that depending upon the
Land Use Plan adopted; there may be areas where this infrastructure will need to be upsized due to flow
and pressure requirements.
Storm drain infrastructure is available mainly along the State Highway 12 corridor, Donald Street, and
Verano Avenue with some minor infrastructure available in other streets. Depending upon the Land Use
Plan adopted; storm drain infrastructure will likely need to be extended to service parcels that do not
have storm drain infrastructure readily available adjacent to their parcel. For the storm drain
infrastructure it should be noted that there are areas along the westerly side of State Highway 12
corridor where topography will require most likely require extensive storm drain infrastructure
improvements.
Upon review of various dry utility information received, there appears to be an established network of
services adequate to support all three Specific Plan Land Use Alternatives. It is recommended that
overhead utilities continue to be placed underground with future infill development projects. In
addition, there may be streets where infrastructure upgrades are needed to meet demand requirements
for future needs.
1.3 – Special Concerns Related to Infrastructure Improvements
Potential Issues with Existing Utility Infrastructure: Many streets with the Specific Plan Area are serviced by Asbestos Cement Pipe (ACP). Use of this product
was abandoned in the 1970s and the installed pipe is believed to be approaching the end of its 50‐year
design lifespan. Replacement of the Existing ACP pipe is recommended on a project by project basis. The
industry consensus is that ACP use does not pose a health risk to the public, but crushing, cutting, or
removal of the pipe must meet applicable standards for hazardous waste. Both pipe bursting and reaming
are common replacement practices, however recent regulatory advisories state that these methods result
in the creation of regulated asbestos material and contaminated sites
ACP Pipe Replacement Methods Three potential construction methods for ACP pipe replacement are evaluated in the following section. Lining Existing Water Main Installation of a new liner by trenchless construction methods commonly uses a process called cured‐in‐place pipe (CIPP). A resin saturated felt tube is inverted or pulled through an existing main and cured to a hardened state by hot water or steam. This method is more commonly used to rehabilitate sewer mains and large diameter water mains with few bends and service connections. Lining with CIPP is not commonly used for small water systems and would not be cost effective and is therefore, not recommended for water main replacement within The Springs Specific Plan area.
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Pipebursting Existing Water Main Installation of a new pipeline by pulling a bursting device through the existing pipeline and at the same pulling a new pipeline into place is called pipebursting. Since pipebursting would leave all ACP materials in place, the U.S Environmental Protection Agency has determined that this process would create an active asbestos waste disposal site. Therefore, pipebursting is not recommended for use within The Springs Specific Plan area. New Water Main There are two options for the construction of a new water main by open cut excavation. One option consists of the removal and proper disposal of the existing ACP water main and replacement with a new water main in the same trench. The other option is to construct a new parallel water main and abandon the existing ACP water main in place.
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2.0 ‐ Water Distribution Collection Facilities
EBA Engineering (EBA) reviewed existing reports and studies relevant to the Springs Specific Plan area
along with available assessor’s parcel data and complied mapping information. The following
information served as the basis of this evaluation:
County of Sonoma. Sonoma County Assessor’s Parcel Data & GIS
County of Sonoma. General Plan and Existing Zoning Maps
Valley of the Moon Water District (VOMWD). Standard Plans, 2015.
Valley of the Moon Water District. 2015 Urban Water Management Plan (UWMP), June 2016.
Valley of the Moon Water District. 2015 Urban Water Management Plan Water Demand
Analysis and Water Conservation Measures Update (UWMP), July 2015.
Valley of the Moon Water District. Urban Water Shortage Contingency Plan (UWSCP), 2014.
Sonoma Local Agency Formation Commission (LAFCO), Municipal Services Review (MSR),
November 2004.
Existing Infrastructure Summary Appendix A, Table 1‐2 provides a summary of the existing water infrastructure available to each public street within the Specific Plan area. This table catalogs pipe sizes, materials, and available pressure information. This information is based on record plan information and data provided from VOMWD. Further verification should be performed on a project by project basis before new infrastructure design is performed.
Water is supplied to the VOMWD by the SCWA, a regional wholesaler, and it is delivered to the Specific
Plan area by the Sonoma Aqueduct. Turnout points are spread out along the Highway 12 corridor where
the regional system is supplied by metered connections. In addition, VOMWD owns seven wells of
which five are in operation. The system is comprised of water mains ranging in size from 4” to 12”
diameter, and the overwhelming majority are between 6” and 8” diameter.
Existing Supply Connections and Municipal Production Wells within or adjacent to the Specific Plan area:
Hanna Turnout – 10” SCWA meter at 16” SCWA Aqueduct
Agua Caliente Turnout – 6” SCWA meter at 16” SCWA Aqueduct
Altimira Turnout – 6” SCWA meter at 16” SCWA Aqueduct
Boyes Boulevard Turnout – 6” SCWA meter at 16” SCWA Aqueduct
Verano and Main Turnout – 6” SCWA meter at 16” SCWA Aqueduct
Verano and Fifth Turnout– 6” SCWA meter at 16” SCWA Aqueduct
Agua Caliente – Well and pump station (active, 120 gpm)
Park Avenue – Well (active, 90gpm)
Mountain Avenue – Well (not in service)
Donald Street – Well, tanks, and pump station (active)
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According to the Urban Water Management Plan a significant number of smaller mains have been
replaced in the last 10 years due to aggressive capital improvement programs, which are ongoing. Most
properties within the Specific Plan Area are supplied from the Sonoma Aqueduct’s Pressure. Parcels
located at higher elevation are served by separate pressure zones, the VOMWD has a total of eleven
pressure zones.
Design Criteria In general, water system facilities will be designed in accordance with accepted engineering principles and will conform to the Valley of the Moon Water Districts’ Standard Plans and Specifications.
2.1 ‐ Analysis
The following methodology for analysis was based on data obtained from the Valley of the Moon Water
District’s UWMP and conversations with District Staff. Additional review and comment from the
VOMWD is needed to confirm assumptions and methodology used in this report.
Water Usage Projections
Water use projections are based on population and use assumptions developed for each of the
proposed Specific Plan Land Use Alternatives. Total actual and projected retail demand by customer
type is shown in Table 2‐1. These volumes were derived by dividing the total water demand in each
category by the total number of customer accounts of that category to determine the average annual
water demand per connection. This data was obtained from the 2015 Urban Water Management Plan
Water Demand Analysis and Water Measures Update. Actual and projected water demand per customer
connection, for the years 2020 to 2040, are as follows:
Table 2‐1 Actual and Projected Water Demand per Customer Connection
Year*
2015 0.30 afy 1.20 afy 1.70 afy 1.19 afy 1.58 afy 2.94 afy
2020 0.29 afy 1.18 afy 1.67 afy 1.17 afy 1.58 afy 2.94 afy
2025 0.29 afy 1.16 afy 1.67 afy 1.17 afy 1.46 afy 2.97 afy
2030 0.29 afy 1.13 afy 1.71 afy 1.17 afy 1.54 afy 2.94 afy
2035 0.29 afy 1.11 afy 1.71 afy 1.17 afy 1.54 afy 2.97 afy
2040 0.29 afy 1.09 afy 1.68 afy 1.17 afy 1.54 afy 2.95 afy
Single Family Multi Family Commercial InstitutionalMulti Family
Irrigation Irrigation
Commercial
*From the 2015 Urban Water Management Plan Water Demand Analysis and Water Measures Update (UWMP), July 2015
**Excluded Non‐Revenue Water
The bold values indicate the highest demand from each customer category in Table 2‐1 as the basis for a
conservative estimate of annual customer water demand. Per the UWMP losses are defined as the
difference between total water produced and total water sold to customers. Unmetered water use
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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includes system maintenance flushing, system leaks, fire protection use, meter errors, and unauthorized
connections. The following Table 2‐2 illustrates the average loss per account within the district.
Table 2‐2 Actual and Projected Losses per Connection
Year*
2015 345 afy 6,884 0.050 afy
2020 352 afy 7,084 0.050 afy
2025 354 afy 7,186 0.049 afy
2030 352 afy 7,288 0.048 afy
2035 351 afy 7,390 0.047 afy
2040 352 afy 7,492 0.047 afy
Losses Accounts
Total System Total Loss per
Account
*From the 2015 Urban Water Management Plan Water Demand Analysis and Water Measures Update (UWMP), dated July 2015
**Excluded Non‐Revenue Water
Adding losses to the Projected Water Demand per Customer Connection results in an Average Net Projected Water Demand for each customer connection type as shown in Table 2‐3. The largest demand for each connection type, from Table 2‐1, was selected and added to projected losses from Table 2‐2 to yield a conservative demand factor of Average Net Projected Water Demand per Connection, as shown in the Table below.
Table 2‐3 Average Net Projected Water Demand per Connection ‐ Conservative Estimate
Year
Retail* 0.30 afy 1.20 afy 1.71 afy 1.19 afy 1.58 afy 2.97 afy
Losses** 0.05 afy 0.05 afy 0.05 afy 0.05 afy 0.05 afy 0.05 afy
Total 0.35 afy 1.25 afy 1.76 afy 1.24 afy 1.63 afy 3.02 afy
CommercialMulti Family Commercial Institutional
Irrigation Irrigation
Single Family Multi Family
*Per Retail Connection, Based on Worst Case Demand From the 2015 Urban
Water Management Plan Water Demand (UWMP), dated July 2015
**Losses based on Total Losses/ Total Accounts From the 2015 UWMP
These demand per connection factors can then be applied to each proposed Land Use Alternative’s
density change to determine the projected increase in number of connections and future possible
demand. Using these factors we are able to estimate the net increase in density for each land use
category proposed by the Specific Plan Alternatives and provided general evaluation for each street.
In doing so, a number of assumptions were made based on the number of multi family dwelling units
per water connection, the square footage of commercial/ retail space per water connection, and the
future number of irrigation connections associated with buildout. These assumptions are outlined in
Table 2‐4, Future Water Connection Factors, and are used to approximate the number of future
connections and determine total demand for each land use alternative.
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Table 2‐4 Future Water Connection Factors
Factor Applied per
Land Use Category Unit of Measurement Unit of Measurement to
Customer Connection Type Determine Future Connections
Single Family
Low Density Res. 1 D.U. 1.0
Med. Density Res. ‐ Alternatives 2 D.U. (Duplexes ‐ 8D.U./ Acre)1
1.0
Rural Residential 1 D.U. 1.0
Multi Family
High Density Res. ‐ Alternative 1 10 D.U. (Assume 20 D.U./ Acre)2
1.0
High Density Res. ‐ Alternative 2 7 D.U. (Assume 14 D.U./ Acre)3
1.0
Limited Commercial Res. Units 1 D.U. (Assume separate meters) 1.0
Neighborhood Com. Res. Units 1 D.U. (Assume separate meters) 1.0
Retail Bus. & Service Res. Units 1 D.U. (Assume separate meters) 1.0
Spring Mixed Use ‐ Alternative 1 12 D.U. (Assume 36.3 D.U./ Acre)4
1.0
Spring Mixed Use ‐ Alternative 2 8 D.U. (Assume 23.8 D.U./ Acre)5
1.0
Springs Recreation Res. Units 1 D.U. (Assume separate meters) 1.0
Multi Family Irrigation
All 6 Multi Family Connections6
1.0
Commercial
Admin. and Pro. TS Overlay 1,000 Sq. ft.7
1.0
Admin. and Professional Office 1,000 Sq. ft.7
1.0
Limited Commercial 1,000 Sq. ft.7
1.0
Neighborhood Commerial 1,000 Sq. ft.7
1.0
Retail Bus. & Service 1,000 Sq. ft.7
1.0
Spring Mixed Use 1,000 Sq. ft.7
1.0
Commercial Irrigation
All 6 Multi Family Connections8
1.0
Institutional
Springs Recreation 5,000 Sq. ft.8
1.0 1Assumed ultimate development is average 0.25 acre projects at 8 D.U./ Acre 2Assumed ultimate development is average 0.5 acre projects at 20 D.U./ Acre 3Assumed ultimate development is average 0.5 acre projects at 14 D.U./ Acre 4Assumed ultimate development is average 0.33 acre projects at 36.3 D.U./ Acre 5Assumed ultimate development is average 0.33 acre projects at 23.8 D.U./ Acre 6Assumed 1 Irr. Connection to every 6 Multi Family Connections, to be verified by VOMWD 7Assumed 1 Connection per 1,000 Sq. feet Matching Sewer ESD Factors 8Assumed 1 Connection per 5,000 Sq. feet to account for varied uses for developed space
Fire supply connections have negligible demand and therefore are assumed not to be included in the UWMP’s number of accounts by customer category. Per VOMWD, it is common for some mixed use, retail, and multi family developments to have separate connections for individual units, because of this assumptions were made regarding the number of dwelling units and would be separately metered. In
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addition, in this estimate 1,000 square feet of projected commercial/ retail square footage is equal to 1 commercial connection. This matches ESD factor used to estimate sanitary sewer flows. Based on the future water connection factors, from Table 2‐4, along with the estimated dwelling units and square footages of residential and commercial buildout of each Land Use Plan Alternative the following is an estimate of the future water demand for The Springs Specific Plan area.
Comparison of Projected Water Use Demands
Alternative 1 Assumed buildout projection of the Specific Plan Area as proposed in
Land Use Circulation Alternative Map 1.
Proposed Density Increase:
652 Dwelling Units + 256,328 Non‐Residential Square Footage
Proposed Water Use Demand:
481.17 acre feet/ year See Table 2‐5
Alternative 2 Assumed buildout projection of the Specific Plan Area as proposed in
Land Use Circulation Alternative Map 2.
Proposed Density Increase:
277 Dwelling Units + 183,540 Non‐Residential Square Footage
Proposed Water Use Demand:
329.31 acre feet/ year See Table 2‐6
Alternative 3 Assumed buildout projection of the Specific Plan Area per the existing
General Plan land use designations.
Proposed Density Increase:
44 Dwelling Units + 141,093 Non‐Residential Square Footage
Proposed Water Use Demand:
205.16 acre feet/ year See Table 2‐7
The following Tables illustrate how net increases in new dwelling units and non‐residential square footages are used to approximate the projected net increase in new water connections and demand for each customer type with each Specific Plan Alternative.
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Table 2‐5 Alternative 1: Development Buildout Projection of Increased Demand
Net Increase in Net Increase in
Connection New Dwelling Non‐Residential
Type Units Sq. Feet
Single Family 95 0.35 afy 24.95 afy
Low Density Res. 49 49
Med. Density Res. 46 23
Multi Family 557 1.25 afy 78.11 afy
High Density Res. 194 19
Spring Mixed Use 349 29
Neighborhood Com. Res. Units 6 6 **
Springs Recreation Res. Units 8 8
Multi Family Irrigation 1.76 afy 18.33 afy
Commercial 225,619 1.24 afy 279.79 afy
Admin. and Professional Office 16,072 16
Spring Mixed Use 189,957 190
Neighborhood Commerial 19,590 20
Commercial Irrigation 1.63 afy 61.42 afy
Institutional 30,709 3.02 afy 18.56 afy
Springs Recreation 30,709 6
Total Projected Net Increased Demand: 481.17 afy
Net Increase in
Water Demand
Projected Water
Demand Per Connection
Including Losses
62
10
226
38
6
Projected
Net Increase in New
Water Connections
72
**Assumes separate metered connections ‐ Conservative Estimate
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Table 2‐6 Alternative 2: Development Buildout Projection of Increased Demand
Net Increase in Net Increase in
Connection New Dwelling Non‐Residential
Type Units Sq. Feet
Single Family 104 0.35 afy 21.88 afy
Rural Residential 1 1
Low Density Res. 20 20
Med. Density Res. 83 42
Multi Family 173 1.25 afy 54.22 afy
High Density Res. 42 6
Spring Mixed Use 107 13
Neighborhood Com. Res. Units 15 15 **
Springs Recreation Res. Units 9 9 **
Multi Family Irrigation 1.76 afy 12.72 afy
Commercial 142,822 1.24 afy 177.10 afy
Admin. and Professional Office 35,502 36
Spring Mixed Use 76,221 76
Neighborhood Commerial 31,099 31
Commercial Irrigation 1.63 afy 38.80 afy
Institutional 40,718 3.02 afy 24.59 afy
Springs Recreation 40,718 8
Total Projected Net Increased Demand: 329.31 afy
Projected Water
Demand Per ConnectionNet Increase in New
Projected
Net Increase in
Including Losses Water DemandWater Connections
63
43
7
143
24
8
**Assumes separate metered connections ‐ Conservative Estimate
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Table 2‐7 Alternative 3: Development Buildout Projection of Increased Demand
Net Increase in Net Increase in
Connection New Dwelling Non‐Residential
Type Units Sq. Feet
Single Family 28 0.35 afy 8.40 afy
Low Density Res. 20 20
Med. Density Res. 8 4
Multi Family 16 1.25 afy 20.00 afy
Retail Bus. & Service Res. Units 3 3 **
Limited Commercial Res. Units 13 13 **
Multi Family Irrigation 1.76 afy 4.69 afy
Commercial 95,677 1.24 afy 118.64 afy
Admin. and Professional Office 5,397 5
Admin. and Pro. TS Overlay 6,779 7
Retail Bus. & Service 36,486 36
Limited Commercial 47,015 47
Commercial Irrigation 1.63 afy 25.99 afy
Institutional 45,416 3.02 afy 27.43 afy
Springs Recreation 45,416 9
Total Projected Net Increased Demand: 205.16 afy
Projected Water
Demand Per Connection Net Increase in
9
Net Increase in New
Water Connections
24
16
3
96
16
Projected
Including Losses Water Demand
**Assumes separate metered connections ‐ Conservative Estimate
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Proposed Utility Capital Improvement Projects:
The VOMWD has indicated that they have the following capital improvement projects proposed in the
near vicinity of the Springs Specific Plan boundary:
1) Lomita Avenue Mainline Upgrades (north end of Lomita Avenue and outside of the Springs
Specific Plan boundary)
2) Boyes Boulevard Bridge Mainline and Valve Replacements (west side of Boyes Boulevard and
outside of the Springs Specific Plan boundary)
3) Malek Road Mainline Upgrades
4) Mainline Valve Replacement at Various Locations
2.2 ‐ CONCLUSION
Existing water utility infrastructure generally appears adequate to support the needs of increased
density for all three Specific Plan Land Use Alternatives. Upgrades to existing aging pipe networks and
appurtenances should be considered with future capital improvement projects and with individual
developments. Water supply issues related to overall demand increase are beyond the scope of this
report and should be further evaluated with Valley of the Moon Water District and their supplier(s).
Recommendations
Infrastructure recommendations are similar for each proposed land use plan. Table 2‐8 summarizes
these recommendations and notes where existing infrastructure is adequate or where new
infrastructure should be considered to adequately service the LUP Alternatives. As development occurs
throughout the Specific Plan, each project will need to be analyzed on a project by project basis to
determine the extents of water infrastructure upgrades needed. Factors that will determine the extents
of the improvements will include at a minimum:
• The type and size of the project;
• Any known pressure issues associated with the greater area where a project is proposed;
• The location of the project in relation to the existing infrastructure; and
• The capacity of the existing infrastructure to account for the planned development.
Capital Improvement Projects to replace Asbestos cement pipe (ACP), also known as transite, may need
to be considered as most municipal waters systems utilizing ACP are nearing the end of their lifespans.
See Section 1.3, Special Concerns Related to Infrastructure Improvements, for additional information
related to ACP replacement’s health and environmental issues.
The VOMWD has indicated that if there are large quantities of proposed infill projects occurring in the vicinity of Verano Avenue and Donald Street that there could be issues with their water storage facilities. Additional analysis is needed to determine if storage capacity is adequate or if enlargement is needed.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Table 2‐8 Suggested Water Infrastructure Improvements
Street Name Proposed Improvements Notes
Agua Caliente Road• The 8" Water main in road is adjacent to the Specific Plan Boundary.
Assess Condition of ACP main and develop replacement strategy for
future failures.
2
Academy Lane
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Arroyo Road
• Partial service available on Arroyo Road withing the Specific Plan
boundary. Suggest connection between Hwy 12 and uppper reach be
installed with future buildout to complete grid distribution system.
2
Balsam Avenue 3
Bernhard Avenue
• No service available on Bernhard Avenue withing the Specific Plan
boundary. Suggest connection between Hwy 12 and Balsam Street be
installed with future buildout to complete grid distribution system.
1, 2
Bonita Way 2
Boyes Boulevard
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Calle Del Monte
• The 8” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Central Avenue
Depot Road 2
East Thomson Ave.
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Encinas Lane 2
ACP = Asbestos Cement, PVC = Polyvinyl Chloride, N/A = Not Available, UNK = Unknown
DIP = Ductile Iron Pipe, PSI = Pound Per Square Inch
Cedar Street 2
Donald Street
• The ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
Fairview Lane 2
• The ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
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Table 2‐8 cont. Suggested Water Infrastructure Improvements
Street Name Proposed Improvements Notes
Fetters Avenue 2
Greger Street 2
Hawthorne Avenue 2
Johnson Avenue
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Keaton Avenue 2
Litchenberg Avenue 2
Madera Road 2
Main Street 2
Malek Road 2
Manzanita Road
Marin Avenue 2
Monterey Avenue 2
Mountain Avenue
• The 8” ACP main located in Mountain Avenue is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
2
Mulford Lane 2
Old Maple Lane
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Robinson Road
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
Sierra Drive
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
First Avenue 2
2
3
Lomita Avenue 2
Harley Street
Hooker Avenue
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
• Very low pressure, additional infastructure improvements may be
needed to support the build‐out of land use alternatives 1 and 2.
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Table 2‐8 cont. Suggested Water Infrastructure Improvements
Street Name Proposed Improvements Notes
Sunnyside Avenue 2
Vailetti Drive
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
2
Vallejo Avenue 2
Waterman Avenue
• The 6” ACP main located in thg road is nearing the end of its design
l ifespan. Assess Condition of ACP and develop replacement strategy for
future failures/ upgrades. Recommend replacement with PVC C‐900 or
equal.
3
ACP = Asbestos Cement, PVC = Polyvinyl Chloride, N/A = Not Available, UNK = Unknown
DIP = Ductile Iron Pipe, PSI = Pound Per Square Inch
2
Notes:
1) Infrastructure improvements may require the extension of existing infrastructure to developed
location. Extents of improvements will be determined based on project type and location.
2) Pressure data not availavle, within the Specific Plan area, at the time of this evaluation.
3) Low pressure my be encountered depending a variety of factors. Private deveopment to install booster
pumps or possible CIP to increase system pressure.
2
3State Highway 12
Verano Avenue
West Thomson Ave.
Siesta Way
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
• The portion of ACP main located in thg road is nearing the end of its
design lifespan. Assess Condition of ACP and develop replacement
strategy for future failures/ upgrades. Recommend replacement with PVC
C‐900 or equal.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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3.0 ‐ Sanitary Sewer Collection Facilities
EBA Engineering (EBA) reviewed existing reports and studies relevant to the Springs Specific Plan area
along with available assessor’s parcel data and complied mapping information. The following
information served as the basis of this evaluation:
County of Sonoma. Sonoma County Assessor’s Parcel Data & GIS.
County of Sonoma. Sonoma County General Plan and Existing Zoning Maps.
Sonoma Valley County Sanitation District (SVCSD). Sanitation Code, December 2013.
SVCSD. Sewer System Management Plan (SSMP), June 2016.
SVCSD. Sphere of Influence (SOI) Expansion Master Plan, December 2013.
Sonoma Local Agency Formation Commission (LAFCO). Municipal Services Review (MSR),
November 2004.
Sonoma County Water Agency (SCWA). Design and Construction Standards for Sanitation
Facilities, updated February 2009.
SCWA. Capital Projects Plan FY 2016/2017 ‐ 2020/2021, 2016.
SCWA, SVCSD, RRCSD, & OCSD. Sewer System Overflow Emergency Response Plan, June 2016.
Existing Infrastructure Summary The Springs Specific Plan areas is with the Urban Services Area of the SVCSD. The Northern one third of
The Springs Specific Plan area is serviced by and existing 18” RCP sewer trunk main located in Malek
Road and existing the Specific Plan area at Lichtenberg Avenue. This trunk main runs in tandem with an
18” DIP/ VCP I & I relief sewer line.
Inflow & Infiltration (I&I) consists of non‐sanitary flows that enter the sanitary sewer system. The SVSD
has indicated that they have issues with Inflow & Infiltration (I&I) in their existing sewer infrastructure
throughout the Sonoma Valley, including areas within the limits of the Springs Specific Plan boundary.
Exact locations of the issues were not provided but EBA has provided civil engineering services on
projects within the limits of the Springs Specific Plan boundary in which SVSD has indicated issues with
sewer overflowing the system during large rain events. These areas include sewer mains located in
Vailetti Drive near State Highway 12 and the sewer trunk main located in the Rancho Vista Trailer Park.
The SVCSD treatment plant is located south of the City of Sonoma in Schellville. The plant is the largest
County sanitation treatment plant and is currently treating an Average Dry Weather Flow of 2.7 million
gallons per day (mgd). Per the SCWA the facility is permitted to treat an Average Dry Weather Flow of
up to 3.0 mgd. The winter an average wet weather maximum flow of 11 mgd is can be treated of an
average Peak Wet Weather Flow of 22 mgd.
Inflow and Infiltration Per the Sonoma Valley County Sanitation District (SCVSD) many of the pipes in the Springs Specific Plan
Area are more than 50 years old. During heavy rain events the system overloads and sewage can flow
into local creeks. One of the major contributing factors to sewer system overflow is ‘inflow and
infiltration’ of storm water runoff and groundwater. These additional flows are the result of seepage
into existing deteriorated laterals and sewer mains and increase the amount of water flowing to the
District’s treatment facility. This additional water entering the system increases both pumping and
sewage treatment costs.
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During large storms, sewer often overflows into creeks that flow into San Pablo Bay; as a result the
Sonoma Valley County Sanitation District (SCVSD) was fined, in 2011 and 2015, by the San Francisco Bay
Regional Water Quality Control Board. The SCVD is currently in the process of creating an ordinance
addressing inflow and infiltration from private homes and businesses. Per the SVCSD an estimated two‐
thirds of the sewer laterals in Sonoma Valley are at least 30 years old and likely in need of repair. The
proposed Sewer Lateral Ordinance would require property owners of homes and businesses that are 30
years or older to have private sewer laterals inspected and repaired, if necessary, to prevent sewer
overflows. Under the proposed ordinance the SVCSD will offer free inspections of private sewer laterals,
rebates of up to $1,000 for repairs (offered for a limited time), and possibly a low interest loan program
to aid property owners in paying for repairs.
Design Criteria Generally public sewer main should be sized to serve the entire tributary area at buildout densities
conforming to the General Plan’s Land Use. Engineers for future individual developments may be
required to provide collection system upgrades based on sewer system calculations or wastewater
modeling. Upgrades will also require additional calculations to determine if minimum velocities are
achieved to ensure proper conveyance and ‘scour’ within sewer mains.
In general, sewer system conveyance shall be designed in accordance with accepted engineering principles and will conform to the Sonoma County Valley Sanitation District’s Standard Plans and specifications. Per SVCSD and SCWA Sanitation Code and Design and Construction Standards public sewer main size shall be a minimum eight (8) inches diameter.
3.1 – Analysis
The following methodology for analysis was based on data obtained from the Sonoma Valley County
Sanitation District’s Sewer Management Plan, industry standard practices, and Sonoma Valley CSD SOI
Expansion Master Plan prepared for the Sonoma County Water Agency. Additional review and
comment from the SVCSD and the SCWA is needed to confirm assumptions and methodology used in
this report.
Flow Determination
Preliminary waste water flow projections for the existing land use as well as the three proposed Land
Use Plan Alternatives were analyzed for Average Dry Weather Flow (ADWF), Peak Dry Weather Flow
(PDWF), and Peak Wet Weather Flow (PWWF).
Average Dry Weather Flow (ADWF) values were used as the basis for Peak Dry Weather Flow (PDWF)
and Peak Wet Weather Flow (PWWF) projections that are used for sizing infrastructure. For the Specific
Plan area, ADWF projections were estimated by utilizing Assessor’s parcel data to determine the
approximate number of residential dwelling units and the square footages of commercial and industrial
space. These counts were then converted to Equivalent Single‐Family Dwelling Units (ESD) and flows
per the SCWA’s Design and Construction Standards for Sanitation Facilities, Sanitary Area Flow
Characteristics (Drawing Number 138), see Appendix B, Attachment 1. Per the SCWA the ADWF per ESD
in the Sonoma Valley District is 200 gpd/ESD.
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Additional Land Use ESD Factors were estimated, based on SCWA data and the City of Sonoma’s
standards; these were used to convert square footages of existing and proposed Commercial, Retail and
Business Service, Administrative and Professional Office, Mixed Use, Recreation, and Community/ Public
facility land uses to Equivalent Single‐Family Dwelling Units. Table 3‐1 lists the ESD factors applied to
various units of measurement.
Table 3‐1 Summary of the ESD Factors Utilized
ESD Factor Applied per
Unit of Measurement to
Determine Land Use's ESD
Other Business and Commercial 1,000 Sq. ft. 1.00
Business and Professional Offices 1,000 Sq. ft. 1.00
Restaurants ‐ Dine In Estimated Seating Capacity 0.20
Restaurants ‐ Take Out 1,000 Sq. ft. 2.50
Sevice Station ‐ Gas Gas Pumps 0.50
Sevice Station ‐ Repair Service Bays 0.20
Warehouse/ Self Storage 1,000 Sq. ft. 0.20
Theater Seats 0.05
Medical/ Dental Offices 1,000 Sq. ft. 1.00
Hospital ‐ Covalescent/ Rest Homes Estimated Beds 0.30
Church/ Hall/ Lodge Connections 1.00
School ‐ Elementry Acre 9.3**
Use Category Unit of Measurement
**Approx. 1860 ADWF per Acre, based on City of Santa Rosa Sewer Stds. Estimated 93 occupants at 20 gal/day
Peak dry weather flow was based on the peaking factor equation provided in the SCWA design standards and is determined by multiplying the ADWF by the peak to average ratio of 1.94. Per the SCWA the PDWF per ESD in the Sonoma Valley district is 388 gpd/ESD. The peak wet weather flow was calculated by adding PDWF to rainfall derived inflow and infiltration (RDII); this was done using the SCWA design criteria of 800 gallons per acre per day for RDII. RDII accounts for non‐sanitary flows that enter a sanitary sewer collection system during wet weather events. Collection systems are most often designed to handle PWWF, because RDII values are significant and result in greatly reduced sewer system capacity. Flow Projections
Land Use Alternatives 1‐3, prepared for The Springs Specific Plan, were analyzed against estimated base ESDs and projected flows. An existing base estimate of 1,077 ESD units was approximated based on existing residential connections, second dwelling units, mobile homes, and non‐residential uses as described above using ESD adjustment factors. This base count includes the Fetter’s Apartments, Multifamily and Senior Housing projects under construction at Highway 12 and Vailetti Drive.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Using this base estimate combined with the projected number of dwelling units and square footages of
non‐residential uses for each of the Land Use Alternatives, the following ESD unit estimates were
produced.
ALTERNATIVE 1 Assumed buildout projection of the Specific Plan Area as proposed in
Land Use Circulation Alternative Map 1.
Proposed Density Increase:
652 Dwelling Units + 256,328 Non‐Residential Square Footage = 872 ESDs
Total Development Buildout Projection:
1,077 Existing ESD + 872 Projected ESDs = 1,949 ESDs
ALTERNATIVE 2 Assumed buildout projection of the Specific Plan Area as proposed in
Land Use Circulation Alternative Map 2.
Proposed Density Increase:
277 Dwelling Units + 183,540 Non‐Residential Square Footage = 418 ESDs
Total Development Buildout Projection:
1,077 Existing ESD + 418 Projected ESDs = 1,495 ESDs
ALTERNATIVE 3 Assumed buildout projection of the Specific Plan Area per the existing
General Plan land use designations.
Proposed Density Increase:
44 Dwelling Units + 141,093 Non‐Residential Square Footage = 103 ESDs
Total Development Buildout Projection: 1,077 Existing ESD + 103 Projected ESDs = 1,180 ESDs
Table 3‐2 lists the projected sewer flows for The Springs Specific Plan area. The PWWF increase from Base Estimate to Alternative 3 is insignificant because Alternative 3 represents area buildout. The slight difference is accounted for by a few minor infill opportunities rather than land use density changes proposed in Alternative 1 and 2.
Table 3‐2 The Springs Specific Plan Area – Projected Sewer Flows
Land Use Plan
AlernativeADWF, gdp PDWF, gdp RDII, gpd PWWF, gpd
Base Estimate 215,295 417,672 123,568 541,240
Alternative 3 236,033 457,904 123,568 581,472
Alternative 2 299,059 580,175 123,568 703,743
Alternative 1 389,819 756,249 123,568 879,817
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The following are cursory analysis of significant sewer flow tributary areas within the Specific Plan’s boundary and serviced by the SVCSD.
Highway 12 Aqua Caliente Road to Sonoma Springs Mixed Use Project, 17310 Sonoma Hwy
Proposed land use densities will increase from Low and Medium Density Residential to Neighborhood
Commercial (Alt. 1&2), Medium Density Residential (Alt. 1&2), and High Density Residential (Alt. 1&2).
With the proposed Alternative 1 land use increase to High Density Residential this area will see some of
the greatest increase in peak sewer flows warranting additional analysis, as described in the Vailetti
Drive Section. See Table 3‐3 for Highway 12 Projected Sewer Flows.
There are additional segments of sewer main, in public easements, running parallel to Sonoma Highway; these are located between private parcels fronting Highway 12 or Cedar Street. From record information, these appear to be primarily 6” VCP sewer main and they may need to be upgraded to 8” diameter to meet the current sanitation design standards. This upgrade should be addressed with future build out of the area.
The estimated increase in flows, along the entire length of Highway 12 within the Specific Plan area, are
shown below:
Table 3‐3 Highway 12 – Projected Sewer Flows
Land Use Plan
AlernativeADWF, gdp PDWF, gdp RDII, gpd PWWF, gpd
Existing Condition 126,746 245,887 47,498 293,384
Alternative 3 141,211 273,948 46,992 320,941
Alternative 2 177,327 344,014 46,992 391,006
Alternative 1 220,506 427,781 46,992 474,773
Highway 12 Sonoma Springs Mixed Use Project, 17310 Sonoma Hwy to Balsam Street
Proposed land use densities will increase from primarily Limited Commercial, Retail, and Medium
Density Residential to Neighborhood Commercial (Alt. 1&2), Springs Mixed Use (Alt. 1&2), Medium
Density Residential (Alt.1), and Spring Recreation (Alt.2). The High Density Residential parcels (Alt. 1&2)
are currently under development and connect to the 18” sewer trunk at Rancho Drive via a new 8” PVC
sewer. In addition, a manually controlled 5,000 gallon private sewer holding tank was installed with the
parcels under development to alleviate peak flow concerns. Density changes will result in increased
flows, but the existing pipe sizes appear to be adequate to accommodate the increase barring no
extenuating problems downstream. Peak flow sewer issues should be analyzed and addressed on a
project by project basis as previously mentioned. See Table 3‐3 for Highway 12 Projected Sewer Flows.
Midway between Sunnyside Avenue and Keaton Avenue the existing sewer should be extended, from
either direction, to accommodate future land uses across the highway from the Sonoma Springs Mixed
Use Project. There is an existing 6” VCP sewer main which conveys south to the manhole at Mountain
Avenue; this segment should be upgraded to 8” diameter to meet the current sanitation design
standards.
This area collects and coveys west through an existing 8” VCP from Highway 12, along and crossing
Pequeno Creek, through private parcels near Fetters Avenue to an existing 18” RCP in Johnson Avenue.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Highway 12 Balsam Street to Calle Del Monte
Proposed land use densities will increase from Limited Commercial and Professional Offices to Springs
Mixed Use (Alt. 1&2), Medium Density Residential (Alt.2), and Commercial (Alt.2). This will result in
increased flows, but the existing pipe sizes appear to be adequate to accommodate the increase barring
no extenuating problems downstream. See Table 3‐3 for Highway 12 Projected Sewer Flows.
Vailetti Drive and Tributary Streets As mentioned in the previous section greater peak flows will results from proposed High Density
Residential land use increases near Aqua Caliente Road. As a result, the 8” VCP in Vailetti Drive may be
under sized and become impacted. Greater study of the sewer system, including modeling, should be
undertaken for the tributary area of Hooker Avenue, Aqua Caliente Road, Highway 12, Cedar Street,
Marin Avenue, Sunnyside Avenue, Casabella Drive to determine impacts downstream.
Highway 12 Calle Del Monte to East Thomson Avenue
Proposed land use densities will increase from Limited Commercial and Professional Offices to Springs
Mixed Use (Alt. 1&2), Medium Density Residential (Alt.2), and Commercial (Alt.2). This will result in
increased flows, but the existing pipe sizes appear to be adequate to accommodate the increase barring
no extenuating problems downstream. Extension of the existing sewer mains between Calle Del Monte
and East Thomson Avenue will, most likely, be required to accommodate future development and
increased density. Depending on the scope of future infill projects a portion of 6” VCP north of East
Thomson Avenue should be upgraded to 8” diameter in order to meeting the current sanitation design
standards.
Sierra Drive and West Thomson Avenue
Proposed land use densities will increase from Low Density Residential to High Density Residential (Alt.2)
or Springs Mixed Use (Alt. 1), Medium Density Residential (Alt.2). This will result in increased flows this
area will see significant increases in peak sewer flows and additional analysis is needed. At a minimum
the 6” VCP in West Thomson Avenue should be upgraded to 8” VCP to accommodate the Hight Density
Residential as well as the Mixed Use density increase along the Sonoma Highway tributary.
Highway 12 East Thomson Avenue to Aqua Caliente Creek
Proposed land use densities will increase from Limited Commercial and Retail to Springs Mixed Use (Alt.
2), and Neighborhood Commercial (Alt. 1&2). This will result in increased flows, but the existing pipe
sizes appear to be adequate to accommodate the increase barring no extenuating problems
downstream. This is an existing 6” VCP on the West side of the highway servicing individual parcels. In
addition there is an 8” VCP on the East side collecting flows from the following tributaries: Siesta Way,
Barcelona Drive, Malaga Street, East Thomson Avenue, the area from 1st Avenue up gradient, Baines
Avenue, and Vallejo Avenue up gradient. See Table 3‐3 for Highway 12 Projected Sewer Flows.
These sewer mains converge and convey via public easement to the West, at Aqua Caliente Creek, just
south of Encinas Lane. Depending on the scope of future infill projects the 6” VCP should be upgraded
to 8” diameter in order to meeting the current sanitation design standards. Analyzing the full tributary
area of the existing 8” VCP is beyond the scope of this report and additional investigation should be
undertaken with infill projects to determine the that existing sewer main with provided adequate
capacity.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Manzanita Road
Proposed land use densities may increase from Low Density Residential to Medium Density Residential
(Alt.1). This will result in increased flows, but the existing pipe sizes appear to be adequate to
accommodate the increase barring no extenuating problems downstream. Due to this area’s
conveyance to the 6” VCP in Academy Lane there is little opportunity to upgraded the sewer to 8” VCP
with our significant work downstream. The estimated increase in flows, along Manzanita Road, are
shown below:
Table 3‐4 Highway 12 – Projected Sewer Flows
Land Use Plan
AlernativeADWF, gdp PDWF, gdp RDII, gpd PWWF, gpd
Existing Condition 8,400 16,296 4,728 21,024
Alternative 3 8,600 16,684 4,728 21,412
Alternative 2 8,800 17,072 4,728 21,800
Alternative 1 8,800 17,072 4,728 21,800
Verano Avenue
Increases in land use density along Verano Avenue, between Highway 12 and 5th Street, will vary with
Alternatives 1 and 2. In general increases in zoning with be from B8 (low density residential) to R2 B6
6DU (medium density residential). In addition, this analysis assumes that areas not included in the
Specific plan, on either side of Highway 12 along Verano Ave are at build out and will see little increase
in density. This analysis also accounts for the parcel owned by Sonoma Valley Health and Recreation
Association know as Paul’s Field and its ultimate development potential. The estimated increase in
flows, along Verano Avenue, are shown below:
Table 3‐5 Highway 12 – Projected Sewer Flows
Land Use Plan
AlernativeADWF, gdp PDWF, gdp RDII, gpd PWWF, gpd
Existing Condition 10,000 19,400 12,555 31,955
Alternative 3 11,000 21,340 12,555 33,895
Alternative 2 * 15,800 30,652 12,555 43,207
Alternative 1 * 15,800 30,652 12,555 43,207 *Density increases are spatially different, but analysis of build out yields the same estimate
There are three (3) sections of existing 6” ACP/ VCP sewer located in the roadway and the majority of
the proposed increase in housing units is proposed between Robinson Road and the City of Sonoma
Limits. The eastern portion of this area, between Highway 12 and Robinson Road, is near estimated
build out of the current General Plan and the existing sewer should be more than adequate to handle
the minor increase in projected ADWF and PDWF for Alternative 3.
Assuming that the existing sewer mains are installed at the minimum slope per the current design
guideline (0.0050 ft/ft) the existing mains should be adequate to support the build out of Alternatives 1
and 2. However, sections of sewer main may need to be replaced to ensure a proper velocity of two (2)
feet per second, repair damaged or compromised sections, or prevent other existing adverse conditions
that may exist downstream. This work should be evaluated on a project by project basis against the
SVCSD’s anticipated needs and sewer replacement should be brought up to the current minimum size of
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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8” diameter. ACP and VCP nearing the end of their design lifespans should be replaced as described in
Section 1.3.
A significant area conveys to the existing 6” sewer main in Old Maple Avenue and enters the 21” RCP
trunk, crossing Verano Avenue, just East of Sonoma Creek. This buildout of the ‘Paul’s Field Parcels
bordering Old Maple Avenue opportunities to more efficiently reroute this 6” pipe and upgrade it to 8”
diameter should be analyzed.
Donald Street
Increases in land use density along Donald Street will vary with Alternatives 1 and 2. In general
increases in zoning with be from B8/B7 (low density residential) to R2 B6 6DU (medium density
residential), or R3 B5 15DU (High Density Residential). The estimated increase in flows are shown
below:
Table 3‐6 Highway 12 – Projected Sewer Flows
Land Use Plan
AlernativeADWF, gdp PDWF, gdp RDII, gpd PWWF, gpd
Existing Condition 12,840 24,910 19,250 44,160
Alternative 3 13,440 26,074 19,250 45,324
Alternative 2 17,840 34,610 19,250 53,860
Alternative 1 29,086 56,426 19,250 75,676
There are three (3) sections of existing 6” ACP/ VCP sewer located in the roadway and the majority of
the proposed increase in housing units is proposed between Robinson Road and 5th Street. The Donald
Street area is close to estimated build out of the current General Plan and the existing sewer should be
more than adequate to handle the minor increase in projected ADWF and PDWF for Alternative 3.
Assuming that the existing sewer mains are installed at the minimum slope per the current design
guideline (0.0050 ft/ft) the existing mains should be adequate to support the build out of Alternatives 1
and 2.
However, sections of sewer main may need to be replaced to ensure a proper velocity of two (2) feet
per second, repair damaged or compromised sections, or prevent other existing adverse conditions that
may exist downstream. This work should be evaluated on a project by project basis against the SVCSD’s
anticipated needs and sewer replacement should be brought up to the current minimum size of 8”
diameter. ACP and VCP nearing the end of their design lifespans should be replaced as described in
Section 1.3.
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
*
*
*
*
*
*
*
*
*
*
*
A
B
C
D
E
F
G
HI
J
K
THE SPRINGS SPECIFIC PLAN
SEWER SERVICE AREAS
DECEMBER 2016
Figure 3-1
*
D
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Proposed Utility Capital Improvement Projects:
The SVCSD and SCWA have indicated that they have the following capital improvement projects proposed
in the vicinity of the Springs Specific Plan boundary:
1) According to the SCWA’s Capital Projects Plan, in 2015, the SFBRWQCB issued a cease and desist order to SVCSD for wet weather discharges from its collection system. The order requires SVCSD to complete certain capital improvements by 2024 to address capacity deficiencies in the collection system. This Capital Projects Plan includes substantial investment in trunk main replacement/rehabilitation projects to comply with this order.
2) Upgrade collection system pipe crossings at waterways to prevent damage during high stream flow events. (by 2021)
3) Replace and/or Rehabilitate collection system, pipe and related infrastructure to reduce inflows and infiltration into the system, and accommodate existing peak flows. (by 2023)
4) Trunk Main and Relief Main Replacement in Vista Drive. (scheduled to be replaced by 2024) 5) Agua Caliente Creek Wastewater Pipe Replacement Project. 6) Trunk Sewer Replacement MH90‐3 to MH 136‐5 of an existing 21‐inch Reinforced Concrete Pipe
trunk sewer and manholes constructed around 1958. According to the SCWA’s Capital Projects Plan, in 2015 “This project will replace approximately 9,100 feet of the sewer trunk and appurtenance manholes with new 27‐inch diameter sewer trunk from the intersection of 6th St. West at Studley St. to Happy Lane, including a double siphon crossing of Agua Caliente Creek. The overall project has been split into 3 segments of roughly the same size, in addition to a separate segment for the crossing of Agua Caliente Creek. The 2001 Sonoma Valley County Sanitation District wet Weather Sewer Analysis of the existing trunk system found that much of the existing sewer trunk is inadequately sized to carry the discharge for future District buildout plus the inflow and infiltration from a 20‐year frequency design storm. Additionally, the original RCP trunk sewer is reaching the end of its service life.”
3.3 ‐ Conclusion
The sanitary sewer facilities within the specific plan area appear to be properly sized and in general will
support ultimate buildout of all three Land Use Alternatives prepared for The Springs Specific Plan.
Flows from the Specific Plan area are conveyed to the treatment plant by Trunk Sewer. Flow monitoring
data for trunk sewers was not reviewed as part of this study. Further analysis should confirm that flows
from increased density in the Specific Plan area can be added to these gravity mains without exceeding
the hydraulic capacity of the trunk pipelines. In addition, future analysis should consider the capacities
of existing I&I relief lines running parallel to the trunks and the impacts of increased density upstream.
However, it appears that the trunk pipelines have available capacity to accept The Springs Specific Plan
flows without backups or surcharging; this should be confirmed with additional sewer studies and
modeling to support individual developments. In addition, the SVCSD’s Sewer System Management Plan
should address population increases and increased sewer flows within the Specific Plan area.
Limited research indicates the SVCSD’s Wastewater Treatment Plant had adequate capacity to accept
increased flows from The Springs Specific plan. This should be confirmed with the SCWA and SVCSD
prior to The Springs Specific Plan land use plan finalization.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Recommendations Infrastructure recommendations are similar for each proposed land use plan. The previous text summarizes
these recommendations and notes where existing infrastructure is adequate or where new
infrastructure should be considered to adequately service the LUP Alternatives. As development occurs
throughout the Specific Plan, each project will need to be analyzed on a project by project basis to
determine the extents of sanitary infrastructure upgrades needed. Factors that will determine the
extents of the improvements will include at a minimum:
• The type and size of the project;
• Any known I&I issues associated with the greater area where a project is proposed;
• The location of the project in relation to the existing infrastructure; and
• The capacity of the existing infrastructure to account for the planned development.
Capital Improvement Projects to replace Asbestos cement pipe (ACP), also known as transite, may need
to be considered as most municipal waters systems utilizing ACP are nearing the end of their lifespans.
See Section 1.3, Special Concerns Related to Infrastructure Improvements, for additional information
related to ACP replacement’s health and environmental issues.
Peak flow sewer issues should be analyzed and addressed on a project by project basis, as build out
occurs, with future ordinance changes to address I & I, and with future Capital Improvement Projects.
Inflow from aging sewer mains and private sewer laterals contribute to these overflows. Due to serious
Inflow and Infiltration issues within the existing sewer system. It is our recommendation that
development projects within the Specific Plan area that undertake building renovation, expansion, or
replacement be required to inspect and replace, as needed, existing sewer laterals and private mains in
order to comply with the proposed sewer lateral ordinance and limit any inflow and infiltration.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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4.0 ‐ Storm Drain Infrastructure and Collection Facilities
EBA Engineering (EBA) reviewed existing reports and studies relevant to the Springs Specific Plan area
along with USGS topographic information, assessor’s parcel data and complied land use information.
The following information served as the basis of this evaluation:
U.S. Geological Survey. Sonoma, CA 7.5 Minute Quadrangle Map, 2015.
Sonoma County Water Agency. Flood Control Design Criteria manual, November 1966 revised
August 1983.
Sonoma Valley Storm water Management and Groundwater Recharge Scoping Study,
October 2011.
Sonoma County Water Agency. Boyes Springs/ Agua Caliente Master Drainage, June 1987.
County of Sonoma Department of Transportation and Public Works. Drainage Report for the
State Route 12 Corridor Improvement Project Phase II Stage 2, October 2011.
Federal Emergency Management Agency. Flood Insurance Study ‐ Volume 3, Study Number
06097CV003A, December 2008.
National Flood Insurance Program. Flood Insurance Rate Map (FIRM) 06097C0930E,
06097C0936E, December 2008.
Storm drainage facilities within The Springs Specific Plan area should be designed to prevent localized
flooding by collecting surface runoff through properly sized inlets and conveyance systems. Storm water
ditches, swales and pipes should discharge to existing outfalls at natural waterways wherever possible.
The County’s Department of Transportation and Public Works (DTPW) is responsible for constructing
and maintaining drainage channels and culverts related to all County roadways. In addition, the DTPW
maintains roadside ditches, storm drains, and inlets to enable proper drainage of storm water from
roadways. Additionally, storm drainage within the Highway 12 right of way is under the responsibility of
the State of California and Caltrans. In general, the County of Sonoma is not responsible for drainage
problems occurring on private property.
The Spring Specific Plan area is located within the Phase 2, Term 1 National Pollutant Discharge
Elimination System (NPDES) boundary. The boundary indicates the area is subject to special NPDES
storm water requirements to improve water quality. In particular this boundary is used to determine
where low impact development post‐construction best management practices (LID BMPS) are required
to improve water quality. The greater watershed is regulated by the San Francisco Bay Regional Water
Quality Control Board and Low Impact Development (LID) design should be implemented complying
with County requirements and the Bay Area Stormwater Management Agencies Association’s (BASMAA)
Post‐Construction Manual as applicable. The manual provides design guidance for storm water
treatment and engineered controls that, in general, closely mimic pre‐development hydrology and
utilize on‐site natural features.
All construction sites disturbing 1 or more acres of soil must obtain an NPDES General Permit for
Discharges of Storm Water Associated with Construction Activity from the State Water Resources
Control Board (SWRCB). Construction activities that are subject to this permit include clearing, grading
and ground disturbances.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐2
Existing Infrastructure Summary
The existing storm drain infrastructure and collection facilities contained within the limits of The Springs
Specific Plan (Specific Plan) consist of a mixture of roadside ditches and swales, drain inlets, culverts,
underground drainage facilities, and creeks; which collects and routes sheet flow storm water flowing in
a northeast to southwest direction and into Sonoma Creek. The existing infrastructure is distributed
throughout the limits of the Springs Specific Plan and appears to have been installed as development
occurred within the area. The areas where the majority of the existing infrastructure is present include
the corridor directly adjacent to Highway 12, the area directly adjacent to Boyes Boulevard, and the areas
directly adjacent to Donald Street and Verano Avenue. These improvements appear to have been
constructed as part of public infrastructure and capital improvement projects within the area. Even
though these areas contain drainage infrastructure, they appear to have been planned to improve
drainage for the existing development conditions within the area at the time of their construction. With
potential build out of the area and current drainage regulations and ordinances; such as Phase 2, Term 1
NPDES and LID, the existing infrastructure appears to be inadequate for potential future development
conditions within the Specific Plan.
Table 4‐1 provides a summary of the existing storm drain infrastructure available to each of the watersheds delineated in Figure 4‐1. In addition, a more general street by street summary of the existing infrastructure can be found in Appendix A, Table 1‐3. This information is based on record plan information and field reconnaissance. Further verification should be performed on a project by project basis before new infrastructure design is performed.
FEMA Flood Areas The Springs Specific Plan area is generally located outside of the FEMA 100 year floodplain defined as
Floodway Areas in Zone AE per FIRM 06097C0930E and 06097C0936E. However, parcels located along
Aqua Caliente Creek, south of Encinas Lane and Meadowbrook Avenue, but north of Donald Street are
flood prone areas subject to periodic inundation (1% Annual Chance Flood). These parcels are currently
occupied by mobile homes and any redevelopment in this area will require special review and possible
federal permitting.
Design Criteria In general, storm drain facilities will be designed in accordance with accepted engineering principles and will conform to the Sonoma County Water Agency’s Flood Control Design Criteria manual, Sonoma County Construction Standards, and applicable NPDES and SWRCB requirements.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐3
4.1 ‐ Analysis
Using available existing hydrology, hydraulic calculations, and record improvement drawing information
obtained from the County of Sonoma Permit and Resource Management Department (PRMD) and the
Sonoma County Department of Transportation and Public Works (SCDTPW), in conjunction with field
reconnaissance, EBA reviewed the existing drainage infrastructure within the Specific Plan and is
providing recommendations for new storm drain infrastructure and collection facilities for the three (3)
Land Use Plan (LUP) Alternatives for the Specific Plan; hereby referred to as LUP Alternative 1, LUP
Alternative 2, and LUP Alternative 3. By using the record drawing information and performing field
reconnaissance, EBA was able to determine approximate watershed boundaries, to locate existing
infrastructure within those watersheds, and provide general recommendations for future infrastructure
improvements that would support each of the three LUP Alternatives.
Watershed Delineation
To establish a base condition for the site and the contiguous areas, a watershed runoff review was
conducted using the pre‐construction site conditions (current conditions) for the Specific Plan’s
watershed. Figure 4‐1 provides a graphical representation of each of the watersheds used to analyze
the existing storm drain infrastructure within the Specific Plan boundary. These watersheds were
determined based on existing infrastructure available in which new infrastructure could be developed to
service the Land Use Plan Alternatives. The watersheds depicted in Figure 4‐1 are for graphical
representation and should not be used for a basis of future hydrology and hydraulic design calculations.
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
1
2
4
3
3
3
3
3
3
7
8
5
6
9
10
11
13
14
17
16
15
18
19
12
20
21
23
24
25
22
THE SPRINGS SPECIFIC PLAN
APPROXIMATE WATERSHEDS
DECEMBER 2016
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Figure 4-1
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐4
Table 4‐1 Available Storm Drain Infrastructure Locations
3
4
5
6
7
8
9
12
17
19
20
21
24
25
23Existing underground storm drain system located near the intersection of Verano Road and
Robinson Road.
Existing underground storm drain system located within Verano Avenue.
Existing unnamed drainage channel located on the westerly side of APN 056‐433‐027.
18Existing underground storm drain system located near the intersection of Manzanita Road
and West Thompson Avenue.
Agua Caliente Creek drainage located south of Fairview Lane.
22Existing underground storm drain system located near the intersection of Verano Avenue
and Lomita Avenue.
Existing underground storm drain system located within Donald Street.
Existing underground storm drain system located within Encinas Lane.
Agua Caliente Creek drainage located on the northerly side of the parcels.
Nearest Available Location
1Existing underground storm drain system located at the northeast corner of the intersection
of Agua Caliente Road and Cedar Street.
2Existing underground storm drain system located at the northeast corner of the intersection
of Vailetti Drive and Cedar Street.
Watershed
Area
Existing underground private storm drain system located within Rancho Drive.
Fetters Creek drainage located on adjacent private parcel towards the west.
Fetters Creek drainage located within parcel.
10Existing underground storm drain system located at the northeast corner of De Chene
Avenue and Northside Avenue
11
16Existing underground storm drain system located near the intersection of Sierra Drive and
West Thompson Avenue.
13Existing underground storm drain system located near the intersection of Highway 12 and
Sierra Drive.
14Existing unnamed drainage channel located near the intersection of Mulford Lane and Sierra
Drive.
Fetters Creek drainage located at the easterly side of the parcel.
Fetters Creek drainage located on the westerly side of parcels
Existing underground storm drain systems located at multiple locations along Highway 12.
Existing underground public and private storm drain systems located on private property.
15Existing unnamed drainage channel located near the intersection of Mulford Lane and Sierra
Drive.
Existing underground storm drain system located near Greger Street and Northside Avenue,
which connects to an existing underground storm drain
Existing underground storm drain system located within private parcel.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐5
Table 4‐1 cont. Available Storm Drain Infrastructure Locations
Notes:
1) Watershed boundaries as shown and described were determined from field observations and may
vary from actual conditions. Topographic surveys and design calculations should be compiled to
determine actual boundaries for final design of any future storm drain infrastructure.
2) Available hydrology/hydraulic calculations on existing drainage infrastructure is minimal and may
require new infrastructure to provide additional calculations showing capacities of the existing
infrastructure.
In the existing, pre‐buildout condition, of the Specific Plan area the majority of watersheds are
substantially developed, with most of the area being gently sloping/ flat with a range of 5 to 15 percent
slopes. The majority of current storm water conveyance with the Specific Plan area is by sheet flow
across multiple private properties to them Public Right. Storm water is then transported by limited
storm drain piping or road side ditches to existing outfalls at Sonoma Creek or its tributaries.
Proposed Utility Capital Improvement Projects: The SCDTPW has indicated that they have the following capital improvement projects proposed in the
vicinity of the Springs Specific Plan boundary:
1) State Highway 12 Improvements from Agua Caliente Road to Boyes Boulevard (currently under construction)
4.2 ‐ CONCLUSION
Buildout of any of the prosed Land Use Plan Alternatives will require flood management controls that
decrease flood flows, increase conveyance, and modify susceptibility to flooding. In addition, low
impact best management practices (BMPs) should be utilized to mimic natural site hydrology. Features
to enhance groundwater recharge should be utilized.
Recommendations
New infrastructure recommendations for each LUP are summarized in Tables 4‐2 thru 4‐4. These
recommendations summarize areas where existing infrastructure is adequate and areas where new
infrastructure would be required to adequately service the LUP Alternatives. As development occurs
throughout the Specific Plan, each project will need to be analyzed on a project by project basis to
determine the extents of the new storm drain infrastructure which will need to be developed for the
project. Factors that will determine the extents of the improvements will include at a minimum:
• The type and size of the project;
• The amount of impervious and pervious surfaces associated with the project;
• The location of the project in relation to the existing infrastructure; and
• The capacity of the existing infrastructure to account for the planned development.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐6
Table 4‐2 LUP Alternative 1 ‐ Proposed Storm Drain Infrastructure Improvements
12• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area.
10
• Public underground drainage infrastructure as required within
Lichtenberg Avenue and De Chene Avenue.
• Connection to existing drainage infrastructure located near the
intersection of De Chene Avenue and Northside Avenue.
1, 4, 5
11
• Public/private underground drainage infrastructure as required within
Greger Street and Boyes Boulevard.
• Connection to existing public drainage infrastructure within Greger Street
and Boyes Boulevard.
1, 4, 5
8
• Private underground drainage infrastructure as required.
• Drainage easements through neighboring parcel(s) with new outlet(s) into
Fetters Creek as required.
1, 2, 4, 5, 6
9• Private underground drainage infrastructure as required.
• New outlet(s) into Fetters Creek as required.1, 2, 4, 5
7• Private underground drainage infrastructure as required.
• New outlet(s) into Fetters Creek as required.1, 2, 4, 5, 6
5
• Public/private underground drainage infrastructure as required within
Malek Road.
• Drainage easement(s) with connection to existing private drainage
infrastructure within Rancho Drive.
1, 4, 5, 6
1
1, 4, 5, 6
6
• Private underground drainage infrastructure as required.
• Drainage easement(s) through neighboring parcel(s) with new outlet(s)
into Fetters Creek as required.
1, 2, 4, 5, 6
Watershed
AreaProposed Improvements Notes
3
• Extension of existing underground drainage systems as required within
Highway 12, Sunnyside Avenue, Keaton Avenue, Mountain Avenue, Fetters
Avenue, Bernhard Avenue, Vallejo Avenue, Arroyo Avenue Hawthorn Avenue,
Siesta Way, and Donald Street.
• Connect to existing drainage infrastructure at various locations along
Highway 12.
1, 3, 4, 5, 6
4• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area. 3, 4, 5
2
1, 4, 5, 6
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure near the intersection of
Agua Caliente Road and Cedar Street.
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure located near the
intersection of Vailetti Drive and Cedar Street.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐7
Table 4‐2 cont. LUP Alternative 1 ‐ Proposed Storm Drain Infrastructure Improvements
24
• Public underground drainage infrastructure as required within Robinson
Road, and Verano Avenue.
• Connection to existing drainage infrastructure located in Verano Avenue.
1, 4, 5, 6
25• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
22• Curent land use for this area is low density residential and drainage
infrastructure is considered to be adequate for this area.
23
• Public underground drainage infrastructure as required within Donald
Street, Robinson Road, and Verano Avenue.
• Connection to existing drainage infrastructure located near the
intersection of Verano Avenue and Robinson Road.
1, 4, 5, 6
20• Area considered to be built out.
• Existing private drainage infrastructure serving the area.
21
• Private underground drainage infrastructure as required.
• Drainage easements through neighboring parcel(s) with new outlet(s) into
Agua Caliente Creek as required.
1, 2, 4, 5, 6
18
• Public underground drainage infrastructure as required within Manzanita
Road.
• Connection to existing public drainage infrastructure located near the
intersection of Manzanita Road and West Thompson Avenue.
1, 4, 5
19
• Public underground drainage infrastructure as required within Manzanita
Road and Fairview Lane.
• New outlet into Agua Caliente Creek through a drainage easement across
APN 056‐611‐045.
1, 2, 4, 5, 6
16
• Public underground drainage infrastructure as required within West
Thompson Avenue.
• Connection to existing drainage infrastructure located within West
Thompson Avenue.
1, 4, 5
17
• Public underground drainage infrastructure as required within West
Thompson Lane and/or private underground infrastructure located on
private property.
• Drainage easement(s) with new outlet(s) to an unnamed drainage channel
located on the westerly side of APN 056‐433‐027.
1, 2, 4, 5, 6
14
• Public underground drainage infrastructure as required within Sierra
Drive and Mulford Lane.
• New outlet(s) into unnamed drainage channel near the Mulford Lane.
1, 2, 4, 5
15
• Public underground drainage infrastructure as required within Sierra
Drive.
• New outlet into unnamed drainage channel near the Mulford Lane.
1, 4, 5
13
• Public underground drainage infrastructure as required within Sierra Dr.
• Connection to existing drainage infrastructure located near the
intersection of Sierra Drive and Highway 12.
1, 4, 5
Watershed
AreaProposed Improvements Notes
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐8
Table 4‐2 cont. LUP Alternative 1 ‐ Proposed Storm Drain Infrastructure Improvements
Notes:
1) Drainage infrastructure improvements may require the extension of existing infrastructure to
developed location. Extents of improvements wil l be determined based on project type and location
within the drainage watershed.
2) Drainage infrastructure improvements wil l require new outfall into existing creek/drainage channel
and may require permitting agency permitting.
3) Hydrology/hydraulic information on existing drainage infrastructure is available.
4) Topographic survey will be required to determine watershed boundaries.
5) Hydrology/hydraulic calculations wil l be required to determine capacity of proposed and existing
storm drain infrastructure.
6) Drainage easements may be required depending upon the extents of the development.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐9
Table 4‐3 LUP Alternative 2 ‐ Proposed Storm Drain Infrastructure Improvements
12• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area.
10
• Public underground drainage infrastructure as required within
Lichtenberg Avenue and De Chene Avenue.
• Connection to existing drainage infrastructure located near the
intersection of De Chene Avenue and Northside Avenue.
1, 4, 5
11
• Public/private underground drainage infrastructure as required within
Greger Street and Boyes Boulevard.
• Connection to existing public drainage infrastructure within Greger Street
and Boyes Boulevard.
1, 4, 5
8
• Private underground drainage infrastructure as required.
• Drainage easements through neighboring parcel(s) with new outlet(s) into
Fetters Creek as required.
1, 2, 4, 5, 6
9• Private underground drainage infrastructure as required.
• New outlet(s) into Fetters Creek as required.1, 2, 4, 5
6
• Private underground drainage infrastructure as required.
• Drainage easement(s) through neighboring parcel(s) with new outlet(s)
into Fetters Creek as required.
1, 2, 4, 5, 6
7• Private underground drainage infrastructure as required.
• New outlet(s) into Fetters Creek as required.1, 2, 4, 5, 6
4• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area. 3, 4, 5
5
• Public/private underground drainage infrastructure as required within
Malek Rd.
• Drainage easement(s) with connection to existing private drainage
infrastructure within Rancho Drive.
1, 4, 5, 6
2
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure located near the
intersection of Vailetti Drive and Cedar Street.
1, 4, 5, 6
3
• Extension of existing underground drainage systems as required within
Highway 12, Sunnyside Avenue, Keaton Avenue, Mountain Avenue, Fetters
Avenue, Bernhard Avenue, Vallejo Avenue, Arroyo Avenue Hawthorn Avenue,
Siesta Way, & Donald St.
• Connect to existing drainage infrastructure at various locations along
Hwy 12.
1, 3, 4, 5, 6
Watershed
AreaProposed Improvements Notes
1
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure near the intersection of
Agua Caliente Road and Cedar Street.
1, 4, 5, 6
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐10
Table 4‐3 cont. LUP Alternative 2 ‐ Proposed Storm Drain Infrastructure Improvements
24
• Public underground drainage infrastructure as required within Robinson
Road, and Verano Avenue.
• Connection to existing drainage infrastructure located in Verano Avenue.
1, 4, 5, 6
25• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
22• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
23• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
20• Area considered to be built out.
• Existing private drainage infrastructure serving the area.
21
• Private underground drainage infrastructure as required.
• Drainage easements through neighboring parcel(s) with new outlet(s) into
Agua Caliente Creek as required.
1, 2, 4, 5, 6
18
• Public underground drainage infrastructure as required within Manzanita
Road.
• Connection to existing public drainage infrastructure located near the
intersection of Manzanita Road and West Thompson Avenue.
1, 4, 5
19
• Public underground drainage infrastructure as required within Manzanita
Road and Fairview Lane.
• New outlet into Agua Caliente Creek through a drainage easement across
APN 056‐611‐045.
1, 2, 4, 5, 6
16
• Public underground drainage infrastructure as required within West
Thompson Avenue.
• Connection to existing drainage infrastructure located within West
Thompson Avenue.
1, 4, 5
17
• Public underground drainage infrastructure as required within West
Thompson Lane and/or private underground infrastructure located on
private property.
• Drainage easement(s) with new outlet(s) to an unnamed drainage channel
located on the westerly side of APN 056‐433‐027.
1, 2, 4, 5, 6
14
• Public underground drainage infrastructure as required within Sierra
Drive and Mulford Lane.
• New outlet(s) into unnamed drainage channel near the Mulford Lane.
1, 2, 4, 5
15
• Public underground drainage infrastructure as required within Sierra
Drive.
• New outlet into unnamed drainage channel near the Mulford Lane.
1, 4, 5
13
• Public underground drainage infrastructure as required within Sierra
Drive.
• Connection to existing drainage infrastructure located near the
intersection of Sierra Drive and Highway 12.
1, 4, 5
Watershed
AreaProposed Improvements Notes
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐11
Table 4‐3 cont. LUP Alternative 2 ‐ Proposed Storm Drain Infrastructure Improvements
Notes:
1) Drainage infrastructure improvements may require the extension of existing infrastructure to
developed location. Extents of improvements wil l be determined based on project type and location
within the drainage watershed.
2) Drainage infrastructure improvements wil l require new outfall into existing creek/drainage channel
and may require permitting agency permitting.
3) Hydrology/hydraulic information on existing drainage infrastructure is available.
4) Topographic survey will be required to determine watershed boundaries.
5) Hydrology/hydraulic calculations wil l be required to determine capacity of proposed and existing
storm drain infrastructure.
6) Drainage easements may be required depending upon the extents of the development.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐12
Table 4‐4 LUP Alternative 3 ‐ Proposed Storm Drain Infrastructure Improvements
1
2
3
4
5
6
7
8
9
10
11
12
13
Watershed
AreaProposed Improvements Notes
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure near the intersection of
Agua Caliente Road and Cedar Street.
1, 4, 5, 6
• Public underground drainage infrastructure as required within Cedar
Avenue and Marin Avenue.
• Connection to existing drainage infrastructure located near the
intersection of Vailetti Drive and Cedar Street.
1, 4, 5, 6
• Extension of existing underground drainage systems as required within
Highway 12, Sunnyside Avenue, Keaton Avenue, Mountain Avenue, Fetters
Avenue, Bernhard Avenue, Vallejo Avenue, Arroyo Avenue Hawthorn Avenue,
Siesta Way, & Donald St.
• Connect to existing drainage infrastructure at locations along Hwy 12.
1, 3, 4, 5, 6
• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area. 3, 4, 5
• Public/private underground drainage infrastructure as required within
Malek Road.
• Drainage easement(s) with connection to existing private drainage
infrastructure within Rancho Drive.
1, 4, 5, 6
• Private underground drainage infrastructure as required.
• Drainage easement(s) through neighboring parcel(s) with new outlet(s)
into Fetters Creek as required.
1, 2, 4, 5, 6
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Private underground drainage infrastructure as required.
• New outlet(s) into Fetters Creek as required.1, 2, 4, 5
• Public underground drainage infrastructure as required within
Lichtenberg Avenue and De Chene Avenue.
• Connection to existing drainage infrastructure located near the
intersection of De Chene Avenue and Northside Avenue.
1, 4, 5
• Public/private underground drainage infrastructure as required within
Greger Street and Boyes Boulevard.
• Connection to existing public drainage infrastructure within Greger Street
and Boyes Boulevard.
1, 4, 5
• Area considered to be built out.
• Existing private and public drainage infrastructure serving the area.
• Public underground drainage infrastructure as required within Sierra Dr.
• Connection to existing drainage infrastructure located near the
intersection of Sierra Drive and Highway 12.
1, 4, 5
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
4‐13
Table 4‐4 cont. LUP Alternative 3 ‐ Proposed Storm Drain Infrastructure Improvements
14
15
16
17
18
19
20
21
22
23
24
25
Watershed
AreaProposed Improvements Notes
• Public underground drainage infrastructure as required within Sierra
Drive and Mulford Lane.
• New outlet(s) into unnamed drainage channel near the Mulford Lane.
1, 2, 4, 5
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Public underground drainage infrastructure as required within Manzanita
Road.
• Connection to existing public drainage infrastructure located near the
intersection of Manzanita Road and West Thompson Avenue.
1, 4, 5
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Area considered to be built out.
• Existing private drainage infrastructure serving the area.
• Private underground drainage infrastructure as required.
• Drainage easements through neighboring parcel(s) with new outlet(s) into
Agua Caliente Creek as required.
1, 2, 4, 5, 6
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
Notes:
1) Drainage infrastructure improvements may require the extension of existing infrastructure to
developed location. Extents of improvements wil l be determined based on project type and location
within the drainage watershed.
2) Drainage infrastructure improvements wil l require new outfall into existing creek/drainage channel
and may require permitting agency permitting.
3) Hydrology/hydraulic information on existing drainage infrastructure is available.
4) Topographic survey will be required to determine watershed boundaries.
5) Hydrology/hydraulic calculations wil l be required to determine capacity of proposed and existing
storm drain infrastructure.
6) Drainage easements may be required depending upon the extents of the development.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
• Current land use for this area is low density residential and drainage
infrastructure is consider to be adequate for this area.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
5‐1
5.0 – Dry Utility Infrastructure and Facilities
EBA Engineering (EBA) reviewed existing utility information supplied by the key service providers with
The Springs Specific Plan area, assessor’s parcel data and complied land use information. The following
information served as the basis of this evaluation:
AT&T. External Map Request for EBA Engineering, March 2016.
Comcast. Facility Request Project SR‐12, Agua Caliente to Fetters ASAG/ Sonoma, March 2016.
Comcast. Facility Request Project SR‐12, Fetters to Hawthorne ASAE/ Sonoma, March 2016.
Comcast. Facility Request Project SR‐12, Hawthorne to Verano ASAD/ Sonoma, March 2016.
Comcast. Facility Request Project SR‐12, Lomita to 5th Street West ASAC/ Sonoma, March 2016.
Pacific Gas & Electric Company. Springs SP Sonoma Electric Distribution Maps 1‐4, March 2016.
Pacific Gas & Electric Company. Springs Specific Plan, Sonoma County Index 8399 Gas Maps,
March 2016.
Dry utility facilities within The Springs Specific Plan area should be designed to provide complete
coverage of services at area buildout. It is anticipated that existing facilities we be need to be upgraded
on project by project basis to meet the demands of each proposed development. In general, the County
of Sonoma is not responsible for dry utility infrastructure and private suppliers will continue to provide
input to and requirements of private development during project entitlement.
Existing Infrastructure Summary
The existing AT&T utility infrastructure and facilities contained within the limits of The Springs Specific
Plan (Specific Plan) consist of a mixture of underground and aerial transmission lines. The existing
infrastructure is distributed throughout the limits of the Springs Specific Plan and appears to have been
installed as development occurred within the area.
An existing Comcast underground fiber is installed within the Highway 12 right of way; this coupled with
overhead lines services nearly the entire Specific Plan area. The existing Comcast infrastructure appears
to be adequate for potential future development within the Specific Plan.
In general Pacific Gas & Electric Company (PG&E) electrical transmission lines have been undergrounded
within the Highway 12 corridor. Overhead lines are still in use along the majority of other streets including
Thomson Avenue, Siesta Way, and Donald Street. The existing electrical infrastructure appears to be
adequate for potential future development within the Specific Plan.
Pacific Gas & Electric Company (PG&E) gas transmission lines are located within Highway 12, W. Agua
Caliente Road, Manzanita Road, Donald Street, Lomita Avenue, and Verano Avenue. Distribution mains
can be found in the majority of other streets with service lines branching to individual parcels. There are
leak survey areas located along the Highway 12 corridor between Mountain Ave. and Agua Caliente Creek.
The existing gas infrastructure appears to be adequate for potential future development within the
Specific Plan.
Table 5‐1 provides a summary of the existing infrastructure available to each street. This information is based on record plan information and field reconnaissance. Further verification should be performed on a project by project basis before new infrastructure design is performed.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
5‐2
5.1 ‐ Analysis
In the existing, pre‐buildout condition, of the Specific Plan area the majority of pacels are substantially
developed and already received dry utility services. The Specific Plan Alternative A will yield the greatest
increase intensity overall and at select locations.
With Land Use Plan Alternative 1, the area along Highway 12 just south of Aqua Caliente Road will
increase in density from low density (single family) residential to High Density Residential. In addition, a
pocket south of Donald Street just west of Robinson Road will increase in density from low density
residential to high density residential, because this area is located in the middle of a larger area of low
density residential this change will see the most disparity between existing services and future needs.
However, the existing services in Donald Street appear to be adequate and may require only minor
upgrades.
Conversely, with Land Use Plan Alternative 2, the area north of Thomson Avenue will experience the
greatest increase in density from low density (single family) residential to High Density Residential.
5.2 ‐ Conclusion
In general, existing PG&E (gas and electric), AT&T, and Comcast infrastructure should be adequate to
support the needs of higher densities, for each land use Alternative, at Specific Plan area build out.
Upgrades to existing systems will need to be considered on a project by project basis. Each utility
provider should evaluate their use projections along with maintenance needs in order to determine the
requirements of future density increases.
Recommendations
The following recommendations summarize areas where existing infrastructure upgrades should be
evaluated along with general recommendations. However, this list is cursory overview and should not
be considered all inclusive.
• The location of future projects in relation to existing infrastructure should be evaluated with each service provider; • The capacity of the existing infrastructure to account for the planned development as well as the future development of the surround area should be considered for each project; • Landlocked parcel should be provided private connections to relevant services as area build out occurs; • Parcels without services should be provided private connection points to relevant services as area build out occurs and infrastructure is extended or upgraded; • Selection of trees species compatible with overhead and underground utilities should be considered with all future development;
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
5‐3
Table 5‐1 Suggested Dry Utility Infrastructure Improvements
Street Name Electric Gas Cable Telecom.
Academy Lane 1, partial 1, partial
Agua Caliente Road N/A
Arroyo Road 1, partial tbd
Balsam Avenue tbd
Bernhard Avenue tbd
Bonita Way 1, partial tbd
Boyes Boulevard 1, partial tbd tbd
Calle Del Monte tbd
Cedar Street 1, partial Central Avenue tbd tbd
Depot Road 1, partial tbd tbd Donald Street East Thomson Avenue Encinas Lane 1 tbd tbd
Fairview Lane 1, partial tbd tbd
Fetters Avenue First Avenue tbd
Greger Street tbd Harley Street Hawthorne Avenue tbd
Hooker Avenue Johnson Avenue 1, partial tbd Keaton Avenue 1, partial Litchenberg Avenue 1, partial Lomita Avenue tbd Madera Road tbd
Main Street 1, partial Malek Road 1, partial 1, partial
Manzanita Road Marin Avenue 1 1, partial 1
Monterey Avenue tbd
Mountain Avenue tbd Mulford Lane tbd tbd tbd
Old Maple Lane tbd
Robinson Road tbd Sierra Drive tbd
Siesta Way State Highway 12 Sunnyside Avenue Vailetti Drive 1, partial tbd tbd
Vallejo Avenue tbd
Verano Avenue 1, partial 1, partial 1, partial
Waterman Avenue tbd
West Thomson Avenue tbd
= Available, N/A = Not Available
1) Utiltiy is not existing in street; utility may not be needed due to service connection point.
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐1
Appendix A
EBA Engineering reviewed existing reports and studies relevant to the Springs Specific Plan area along
with available assessor’s parcel data and complied mapping information. The following information
served as the basis of this evaluation:
Tables – Existing Wet Utility Infrastructure
Table 1‐1 Existing Wet Utility Infrastructure Availability Summary
Table 1‐2 Existing Water System Infrastructure Summary
Table 1‐3 Existing Sewer System Infrastructure Summary
Table 1‐4 Existing Storm Drain Infrastructure Summary
Figures – Base Maps
Figure 1‐1 Water System Base Map December 2016
Figure 1‐2 Sanitary Sewer Base Map December 2016
Figure 1‐3 Storm Drain Base Map December 2016
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐2
Table 1‐1 Existing Wet Utility Infrastructure Availability Summary
Street Name Water Sewer Storm Drain Notes
Agua Caliente Road Arroyo Road Balsam Avenue N/A
Bernhard Avenue N/A
Bonita Way N/A
Boyes Boulevard N/ACalle Del Monte Cedar Street N/A Central Avenue Depot Road N/A
Donald Street East Thomson Avenue N/A
Encinas Lane N/A
Fairview Lane N/A
Fetters Avenue First Avenue N/A
Greger Street Harley Street N/A
Hawthorne Avenue N/A N/A
Hooker Avenue N/A
Johnson Avenue N/A
Keaton Avenue Litchenberg Avenue N/A
Lomita Avenue Madera Road N/A N/A
Main Street Malek Road N/A
Manzanita Road N/A
Marin Avenue N/A N/A
Monterey Avenue N/A N/A
Mountain Avenue Mulford Lane N/A
Old Maple Lane N/A
Robinson Road Sierra Drive N/A
Siesta Way State Highway 12 Sunnyside Avenue Vailetti Drive Vallejo Avenue Verano Avenue Waterman Avenue N/A
West Thomson Avenue = Available, N/A = Not Available
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
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Table 1‐2 Existing Water System Infrastructure Summary
Street Name Size Pipe Type Available Pressure Notes
Agua Caliente Road 8” ACP N/A
Arroyo Road 6” DIP N/A
Balsam Avenue UNK UNK 45 – 55 PSI
Bernhard Avenue N/A N/A N/A
No water available in
street within Specific Plan
Area.
Bonita Way 6” PVC N/A
Boyes Boulevard 6” ACP N/A
Calle Del Monte 8” ACP N/A
Varies
4”‐6”
Central Avenue 6” PVC 55 PSI
Depot Road 6” PVC N/A
Varies
6”‐8”
East Thomson Avenue 6” ACP N/A
Refer to Water System
Base Map for
approximate locations.
Encinas Lane 8” PVC N/A
ACP
PVC
Fetters Avenue 8” PVC N/A
Varies ACP (6”)
6”‐8” PVC (8”)
Greger Street 6” ACP N/A
ACP = Asbestos Cement, PVC = Polyvinyl Chloride, N/A = Not Avai lable, UNK = Unknown
DIP = Ductile Iron Pipe, PSI = Pound Per Square Inch
Refer to Water System
Base Map for
approximate locations.
Refer to Water System
Base Map for
approximate locations.
Refer to Water System
Base Map for
approximate locations.
6” N/A
Refer to Water System
Base Map for
approximate locations.
Fairview Lane
Cedar Street ACP N/A
First Avenue N/A
Donald Street ACP 60 – 70 PSI
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐4
Table 1‐2 cont. Existing Water System Infrastructure Summary
Street Name Size Pipe Type Available Pressure Notes
DIP
Refer to Water System
Base Map for
approximate locations.
PVC
Hawthorne Avenue 6” PVC N/A
PVC
ACP
Johnson Avenue 6” ACP N/A
Keaton Avenue 6” DIP N/A
Litchenberg Avenue 6” ACP N/A
ACP
PVC
Madera Road N/A N/A N/A
Units are served off either
State Highway 12 or First
Avenue.
Main Street 12” PVC N/A
Malek Road 3” UNK N/A
Manzanita Road 6” PVC 55 – 60 PSI
Marin Avenue 6” PVC N/A
Monterey Avenue 6” PVC N/A
Mountain Avenue 8” ACP N/A
Mulford Lane 6” PVC N/A
Old Maple Lane 6” ACP N/A
Robinson Road 6” ACP 55‐75 PSI
Sierra Drive 6” ACP N/A
Varies ACP (6”)
6” – 10” PVC (10”)
Varies ACP (6”) Varies
6” – 12” PVC (12”) 45 – 65 PSI
Sunnyside Avenue 6” DIP N/A
Vailetti Drive 6” ACP N/A
Vallejo Avenue 6” PVC N/A
PVC
ACP
Waterman Avenue 6” ACP 45 – 60 PSI
ACP
PVC
ACP = Asbestos Cement, PVC = Polyvinyl Chloride, N/A = Not Avai lable, UNK = Unknown
DIP = Ductile Iron Pipe, PSI = Pound Per Square Inch
8” 60‐75 PSI
State Highway 12
West Thomson Avenue 6” N/A
Refer to Water System
Base Map for
approximate locations.
N/ALomita Avenue 6”
Refer to Water System
Base Map for
approximate locations.
Siesta Way N/A
6”Hooker Avenue
Verano Avenue
N/A6”
24 – 44 PSI
Harley Street
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐5
Table 1‐3 Existing Sewer System Infrastructure Summary
Flow
Rate
Agua Caliente Road 6” VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Arroyo Road 6” VCP N/A
Balsam Avenue 6” VCP N/A
Bernhard Avenue 6” VCP N/A
Bonita Way 6” VCP N/A
Boyes Boulevard 6” VCP N/A
Calle Del Monte 6” VCP N/A
Cedar Street N/A N/A N/A
Units adjoining street
frontage are serviced
through backyard sewer.
Central Avenue 6” VCP N/A
Depot Road 6” VCP N/A
Donald Street 6” ACP/VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
East Thomson Avenue 6” VCP N/A
Encinas Lane 8” PVC N/A
Fairview Lane 6” ACP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Fetters Avenue 6” VCP N/A
First Avenue 6” VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Greger Street 6” VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Harley Street 6” VCP N/A
Hawthorne Avenue N/A N/A N/A
No sewer available in
street within Specific Plan
Area.
Hooker Avenue 6” ACP N/A
VCP (6”)
RCP (18”)
Keaton Avenue 6” VCP N/A
Litchenberg Avenue 18” RCP N/ATrunk main. No sewer
lateral connections.
Lomita Avenue 6” VCP N/A
Madera Road 6” VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Johnson Avenue 6” & 18” N/A
18” is trunk main. Existing
sewer lateral connections
are to 6”.
VCP = Vitrified Clay Pipe, ACP = Asbestos Cement Pipe, N/A = Not Available
Street Name Size Pipe Type Notes
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐6
Table 1‐3 cont. Existing Sewer System Infrastructure Summary
Flow
Rate
Main Street 6” VCP N/A
VCP (6”)
RCP (18”)
Manzanita Road 6” VCP N/A
Marin Avenue N/A N/A N/A
No sewer available in
street within Specific Plan
Area.
Monterey Avenue N/A N/A N/A
No sewer available in
street within Specific Plan
Area.
Mountain Avenue 8” VCP N/A
Mulford Lane 6” VCP N/A
Old Maple Lane 6” VCP N/A
Robinson Road 6” ACP N/A
Sierra Drive 6” VCP N/A
Varies
6” – 8”
Varies
6” – 8”
Sunnyside Avenue 6” VCP N/A
Vailetti Drive 8” VCP N/A
Vallejo Avenue 6” VCP N/A
Varies
6” – 8”
Waterman Avenue 6” VCP N/A
West Thomson Avenue 6” VCP N/A
VCP (6”)
ACP (6”)
RCP (18”)
Notes
Verano Avenue ACP/ VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
State Highway 12 VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
VCP = Vitrified Clay Pipe, ACP = Asbestos Cement Pipe, N/A = Not Available
Misc. Easements 6” & 18” N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Siesta Way PVC/VCP N/A
Refer to Sanitary Sewer
Base Map for
approximate location.
Malek Road 6” & (2)18” N/A
18” are trunk main &
bypass. Existing sewer
later connections
Street Name Size Pipe Type
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐7
Table 1‐4 Existing Storm Drain Infrastructure Summary
Street Name Size Pipe Type Notes
Agua Caliente Road UNK UNK
Roadside ditches w/ (2) catch basins located of
the easterly side of intersection with State
Highway 12.
Arroyo Road UNK UNK
Roadside ditches w/ (1) catch basin located of
the southeasterly side of intersection with State
Highway 12.
Balsam Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Bernhard Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area
Bonita Way N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Boyes Boulevard N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Calle Del Monte UNK UNK
Mainly sheet flow conditions with (1) catch
basin located near the intersection with State
Highway 12.
Cedar Street UNK UNK
Mainly sheet flow conditions with (2) catch
basin located near the intersection with Vailetti
Drive.
Central Avenue 36” RCP
36” underground storm drain and (3) catch
basins located near the intersection with State
Highway 12.
Depot Road N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Varies
18”‐24”
East Thomson Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Encinas Lane N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Fairview Lane N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Fetters Avenue UNK UNK
Mainly sheet flow conditions with (1) catch
basin located near the intersection with State
Highway 12.
First Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Greger Street UNK UNK
Mainly sheet flow conditions with (1) catch
basin located near the intersection with Pine
Avenue.
Harley Street N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Donald Street RCPRefer to Storm Drain Base Map for approximate
locations.
N/A = Not Available, UNK = Unknown, RCP = Reinforced Concrete Pipe
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐8
Table 1‐4 cont. Existing Storm Drain Infrastructure Summary
Street Name Size Pipe Type Notes
Hawthorne Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Hooker Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Johnson Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Keaton Avenue UNK UNK
Roadside ditches w/ (1) catch basin located of
the northeasterly side of intersection with State
Highway 12.
Litchenberg Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Lomita Avenue UNK UNK
Roadside ditches w/ (2) catch basins located of
the northerly side of intersection with Verano
Avenue
Madera Road N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Main Street UNK UNK
Curb and gutter w/ (1) catch basin located of
the northeasterly side of intersection with
Verano Avenue
Malek Road N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Manzanita Road N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Marin Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Monterey Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Mountain Avenue UNK UNK
Roadside ditches w/ (1) catch basin located of
the southeasterly side of intersection with State
Highway 12.
Mulford Lane N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Old Maple Lane N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Robinson Road UNK UNK
Roadside ditches w/ (2) catch basins located of
the northerly side of intersection with Verano
Avenue and Donald Street.
Sierra Drive N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
Siesta Way UNK UNKCurb and gutter w/ (2) catch basin located near
the intersection with State Highway 12.
N/A = Not Available, UNK = Unknown, RCP = Reinforced Concrete Pipe
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
A‐9
Table 1‐4 cont. Existing Storm Drain Infrastructure Summary
Street Name Size Pipe Type Notes
State Highway 12 Varies VariesRefer to Storm Drain Base Map for approximate
locations.
Sunnyside Avenue UNK UNK
Roadside ditches w/ (2) catch basins located of
the easterly side of intersection with State
Highway 12.
Vailetti Drive Varies VariesRefer to Storm Drain Base Map for approximate
locations.
Vallejo Avenue UNK UNK
Sheet flow with (1) catch basin located of the
southeasterly side of intersection with State
Highway 12.
Verano Avenue Varies Varies
Refer to Storm Drain Base Map for approximate
locations. Need further record drawings for
unknown area.
Waterman Avenue N/A N/ANo known underground storm drain available
in street within Specific Plan Area.
West Thomson Avenue UNK UNKUnderground drainage system present near the
intersection with State Highway 12.
N/A = Not Available, UNK = Unknown, RCP = Reinforced Concrete Pipe
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS SPECIFIC PLAN
WATER SYSTEM BASE MAP
DECEMBER 2016
Figure 1-1
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS SPECIFIC PLAN
SANITARY SEWER BASE MAP
DECEMBER 2016
Figure 1-2
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS
SPECIFIC PLAN
BOUNDARY
THE SPRINGS SPECIFIC PLAN
STORM DRAIN BASE MAP
DECEMBER 2016
Figure 1-3
County of Sonoma The Springs Specific Plan December 9, 2016 Utility Infrastructure Needs Report
B‐1
Appendix B
Sonoma County Water Agency Sanitary Sewer – Sanitary Area Flow Characteristics
SCWA Standard Drawing Number 138
A. THIS PLAN IS BASED UPON NUMBERS FOUND IN THE 2000 U.S. CENSUS.
B. THIS IS THE FLOW FOUND IN THE BILLING BASIS TABLES FOR EACH SANITATION AREA.
C. THIS IS THE AVERAGE DRY WEATHER FLOW PER ESD BASED UPON FLOW RECORDS.
D. THE PEAK DRY WEATHER FLOW IS DETERMINED BY MULTIPLYING THE ADWF (C) BYTHE PEAK TO AVERAGE RATIO (E).
E. THE PEAK TO AVERAGE RATIO WAS DETERMINED BY MULTIPLYING THE ADWF (C) BY ACONSTANT K PRODUCED BY THE FORMULA:
K=5.453/P0.0963 WHERE P=ESTIMATED POPULATION
F. THIS NUMBER COMES FROM THE AGENCY'S MASTER LIST OF BILLING RECORDS ANDIS THE TOTAL NUMBER OF ESDs LISTED FOR EACH SANITATION AREA.
G. THIS IS ARRIVED AT BY MULTIPLYING THE NUMBER OF PEOPLE PER ESD (A) TIMESTHE CONNECTED ESD LOAD (F)
H. PDWF PLUS 800 GALLONS PER ACRE PER DAY RAINFALL DERIVED INFLOW ANDINFILTRATION PRODUCES THE DESIGN PEAK WET WEATHER FLOW (DWWF).
EFFECTIVE JANUARY 1, 2009
1. THE NUMBERS AND FORMULAS USED IN THISTABLE ARE SUBJECT TO CHANGE.
2. PDWF PLUS 800 GALLONS PER ACRE PER DAYRAINFALL DERIVED INFLOW AND INFILTRATIONPRODUCES THE DESIGN PEAK WET WEATHERFLOW (PWWF).
DRAWINGNUMBER:
SCALE: NONE
REVIEWED BY: APPROVED:02/03/09
DATE: 138SANITARY SEWER - SANITARY AREA FLOW CHARACTERISTICS
