7 AD-AI0 024 K IMBALL (L ROBERT) AND ASSOCIATES EBENSBURG PA
FI 13/13NATIONAL DAM SAFETY PROGRAM. LAGUNA P ALMA DAM MNO 30404) MI SS! -ETCIU)
AUG 79 R J KIMBALL, J T HOCKENSMITH DACW43"79-C-0034
UNCLASSIFIED NL
EEEEEEEEDB BrEND
LEVELOMISSISSIPPI - KASKASKIA - ST. LOUIS BASIN
A ., : 0 2 4
LAGUNA PALMA DAM
JEFFERSON COUNTY, MISSOURI
MO 30404 DTICS-ELECTE
OCT 0 6 1981E
PHASE 1 INSPECTION REPORTNATIONAL DAM SAFETY INSPECFON
LUnited kates Army
Corps of Engineers...Seruing the Army
Serving the Nation
St. Louis District
original coontailns 0010
plates: All DTIC reproduot-ions will be in black Md1
PREPARED BY: U.S. ARMY ENGINEFR DISTRICT, ST sThia docurrint has beeri approved
FR SAEOO I for public release and ale; itsFOR: STATE OF MISSOURI d€bibumon Is Unlmite. .
AUGUST 1979
81 10 2 182
I UNCLASSIFIED
SECURITY CLASSIFICATION OF THIS PAGE ( Dohei Dai Entered)_
READ INSTRUCTIONSREPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM
1. REPORT NUMBER 2. GOVT ACCESSION NO. 3. RECIPIENT'S CATALOG NUMBER
4. TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVERED
Phase I Dam Inspection Report
National Dam Safety Program / Final eport,,
Laguna Palma Dam (MO 30404) 6. PERFORMING OG. REPORT NUMBER
Jefferson County, Missouri7. AUTHOR(.) S. CONTRACT OR GRANT NUMBER(&)
L. Robert Kimball and Associates
.... DACW43-79-C-0-34g. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PWoGWOAWr L-ENT'PROJECT, TASK
AREA & WORK UNIT NUMBERS
U.S. Army Engineer District, St. LouisDam Inventory and Inspection Section, LMSED-PD210 Tucker Blvd., North, St. Louis, Mo. 63101 _ o_ _
1. CONTROLLING OFFICE NAME AND ADDRESS J7. REPORT DATE
U.S. Army Engineer District, St. Louis jAugu X979Dam Inventory and Inspection Section, LMSED-PD - 0- "=210 Tucker Blvd.. North. St. Louise Mo. 6ql0l Approximately SO
14. ONIjORhNG AGENCY NAME & ADORESS('If dlrleent from Controlling Office) IS. SECURITY CLASS. (of thle report)
(4 National Dar Safety Program. Laguna
Palma Dam (MO 30404), Mississippi - Kask- UNCLASSIE
askia - St. Louis Basin, Jefferson County.. SCHEDULEMissouri. Phase I Inspection Report.
IS. DISTRIB I
Approved for release; distribution unlimited.
i -"/ [ .... I J117. DISTRIBUTION STATEMENT (of the absttct entered in Blockt t, if dffferent Iem. Reporf)IViiI&. SUPPLEMENTARY NOTES
19. KEY WORDS (Continue on reverse aide If neceeasry and identify by block number)
Dam Safety, Lake, Dam Inspection, Private Dams
A A@STNAC' a Cionth.e so geno able N .esmsy d ideatttp by block number)
This report was prepared under the National Program of Inspection ofNon-Federal Dams. This report assesses the general condition of the dam with
respect to safety, based on available data and on visual inspection, to
determine if the dam poses hazards to human life or property.
SJD " q 1473 EDITION OF I NOV S IS OBSOLETEAn 3 I NCI.A.R.RT FTI .D
SECURTY CLASFICATION Of THIS PAGE ('When Doe Entered)
SICURITY CLASSIFICATION OF THIS PA0S(Whum Data Entm()
SECURITY CLASSIFICATION OF THIS PAGEIUMbe, Data antegd)
PREFACEtThis report is prepared under guidance contained in theRecomended Guidelines for Safety Inspection of Dams, forPhase I Investigacions. Copies of these guidelines may beobtained from the Office of Chief of Engineers, Washington,D.C. 20314. The purpose of a Phase I investigation is toidentify expeditiously those dams which may pose hazards tohuman life or property. The assessment of the general con-dition of the dam is based upon available data and visualinspections. Detailed investigation, and analyses involvingtopographic mapping, subsurface investigations, testing, anddetailed computational evaluations are beyond the scope of aPhase I investigation; however, the investigation is intendedto identify any need for such studies.
In reviewing this report, it should be realized that thereported condition of the dam is based on observations offield conditions at the time of inspection along with dataavailable to the inspection team. In cases where the reservoirwas lowered or drained prior to inspection, such action,while improving the stability and safety of the dam, removesthe normal load on the structure and may obscure certain con-ditions which might otherwise be detectable if inspectedunder the normal operating environment of the structure.
It is important to note that the condition of a dam dependson numerous and constantly changing internal and externalconditions, and is evolutionary in nature. It would beincorrect to assume that the present condition of the damwill continue to represent the condition of the dam at somepoint in the future. Only through frequent inspections canunsafe conditions be detected and only through continuedcare and maintenance can these conditions be prevented orcorrected.
Phase I inspections are not intended to provide detailedhydrologic and hydraulic analyses. In accordance with theestablished Guidelines, the spillway design flood is basedon the estimated "Probable Maximum Flood" for the region(greatest reasonably possible storm runoff), or fractionsthereof. The spillway design flood provides a measure ofrelative spillway capacity and serves as an aid in deter-mining the need for more detailed hydrologic and hydraulicstudies, considering the size of the dam, its general con-dition and the downstream damage potential.
DEPARTMENT OF THE ARMY AcceIo GEArDTIC Tl?i \ ... - ST. LOUIS 0ISrmIC', CORPS OF EN iNE.RS NT'IS GF A
210 NORTH 12TH STREET Unanncc, j
ST. LOUIS, MISSOURI 63101 just i_
By
LMSED-FI Di st ri ut i on/
Avai la i±ity Cods 1
SUBJECT: Laguna Palrna Damn Phase I Inspection Report - Avail rio
Dist Special
This report presents the results of field inspection and evaluationof the Laguna Palma Dam.
It was prepared under the National Program of Inspection ofNon-Federal Dams.
This dam has been classified as unsafe, emergency by the St. LouisDistrict as a result of the application of the following criteria:
1. Spillway will not pass a 10-year frequency flood withoutovertopping of the dam. The spillway is, therefore,considered to be unusually small and seriously inadequate.
2. Overtopping could result in dam failure.
3. Dam failure significantly increases the hazard to life andproperty downstream.
BY: SIGNED 26 FEB1980
Chief, Engineering Division Date
SIGNED 26 FEB 1380APPROVED BY:
Colonel, CE, District Engineer Date
PHASE I REPORT
NATIONAL DAM SAFETY PROGRAM
NAME OF DAM1 Laguna Palma
STATE LOCATED MissouriCOUNTY LOCATED JeffersonSTREEAM West Fork of Plattin CreekDATE OF INSPECTION May 2, 1979
Laguna Palma Dam was inspected using the "RecommendedGuidelines for Safety Inspection of Dams". These guidelineswere developed by the Chief of Engineers, U.S. Army, Washington,D.C., with the help of federal and state agencies, professionalengineering organizations, and private engineers. The resultingguidelines are considered to represent a consensus of theengineering profession.
Based on the criteria in the guidelines, the dam is in thehigh hazard potential classification, which means that loss oflife and appreciable property loss could occur in the event offailure of the dam. The dam is in the small size classificationsince it is greater than 25 feet high,but less than 40 feet high.Within the estimated damage zone approximately three milesdownstream of the dam are ninedwellings, county roads andHighway T.
Based on the downstream affected area the Spillway DesignFlood for this dam is the PMF (probable maximum flood). Thespillway is capable of controlling approximately 3% of thePMF without overtopping the embankment. In addition, thespillway cannot control the 10 year storm.
Deficiencies visually observed for Laguna Palma Dam were noriprap on the upstream slope, cracking of the concrete gravitysection and possible inoperable drain line valve. There isno warning system in effect or a safety inspection program.Stability, stress and seepage analyses comparable to the require-ments of the "Recommended Guidelines for Safety Inspections ofDams" are not available which is considered a deficiency.These deficiencies should be remedied at the direction of aprofessional engineer knowledgeable in the design and constructionof concrete and earth fill dams.
ii
Laguna Palma Dam - MO. 30404
The owner should take action to correct or control thesedeficiencies.
R. JEFFREY KIMBALL, P.E.L. Robert Kimball & AssociatesVice President, Earth Sciences
JAS T. HOCKENSMITHL. Robert Kimball & AssociatesGeologist
XUAG MEI CHUANG, P.E .
L. Robert Kimball & AssociatesHydraulic Engineer
iii
VI
TABLE OF CONTENTS
PAGE
SECTION I - PROJECT INFOELATION I
1.1 General 11.2 Description of Project I1.3 Pertinent Data 2
SECTION 2 - ENGINEERING DATA 5
2.. Design 52.2 Construction 5
2.3 Operation 52.4 Evaluation 5
SECTION 3 - VISUAL INSPECTION 6
3.1 Findings 63.2 Evaluation 8
SECTION 4 - OPERATIONAL PROCEDURES 9
4.1 Procedures 9
4.2 Xaintenance of the Dam 9
4.3 Maintenance of Operating Facilities 9
4.4 Description of any Warning System in Effect
4.5 Evaluation 9
SECTION 5 - HYDRAULIC/HYDROLOGIC 10
5.1 Evaluation of Features 10
SECTION 6 - STRUCTURAL STABILITY 11
6.1 Evaluation of Structural Stability I1
SECTION 7 - ASSESSMENT .UD RECOMMENDATIONS/REMEDIALMEASURES 12
7.1 Dam Assessment 127.2 Recommendations/Remedial Measures 12
v
LIST OF APPENDICES
APPENDIX A - DRAWINGS
APPENDIX B - HYDROLOGY AND HYDRAULICS
APPENDIX C - PIOTOGRAPHS
vi
PHASE I INSPECTION REPORTNATIONAL DAM SAFETY PROGRAm
LAGUNA PALMA DAM - ID NO. 30404
SECTION 1 - PROJECT INFORMATION
1.1 GENERAL
a. Authority. The National Dam Inspection Act, PublicLaw 92-367, authorized the Secretary of the Army, through theCorps of Engineers, to initiate a program of safety inspectionof dams throughout the United States. Pursuant to the above,the St. Louis District, Corps of Engineers, District Engineerdirected that a safety inspection of the Laguna Palma Dam bemade.
b. Purpose of Inspection. The purpose of the inspectionwas to make an assessment of the general condition of the damwith respect to safety, based upon available data and visualinspection, in order to determine if the dam poses hazards tohuman life or property.
c. Evaluation Criteria. Criteria used to evaluate thedam were furnished by the Department of the Army, Office of theChief of Engineers, in "Recommended Guidelines for SafetyInspections of Dams". These guidelines were developed with thehelp of several federal agencies and many state agencies,professional engineering organizations, and private engineers.
1.2 DESCRIPTION OF PROJECT
a. Description of Dam and Appurtenances.
(1) Laguna Palma Dam is an earthfill dam with a concretegravity spillway section. The concrete gravity section isapproximately 90 feet long and 26 feet high. The earth portionof the dam is approximately 440 feet long and 15 feet high. Aearth embankment has a bend in the upstream direction. Theconcrete core wall is located in the earth embankment sectionbetween the concrete gravity section and the bend in the earthembankment. The upstream slope does not contain any riprap.The slope varies from l.5H:lV to 2.5H:IV. The downstream slopeis variable and averages 3H:lV. The downstream slope is grassed.
The spillway is located in the concrete gravity section. Thespillway is trapezoidal in shape with a bottom width of 60 feet. Inthe concrete gravity section six feet below the crest is a 24"cast iron pipe. This pipe is used as a drainline.
Upstream of Laguna Palma Dam is Lake Lacawanna which isan earthfill dam approximately 40 feet high. The spillwayis a trapezoidal shaped earth cut with a bottom width of 12feet.
.. ... ... , - _ .. , . .. . , _ - -- .., ,:,iE -. _ , . . . . , . .1 . . ,u . .I.
b. Location. Laguna Palma Dam is located approximately4.5 miles east of Vales Mines, Missouri on the Test Fork ofPlattin Creek. The dam can be located (Section 36, Township 39North, Range 5 East) on the Halifax, Missouri 7.5 minute U.S.G.Squadrangle.
c. Size Classification. Laguna Palma Dam is a small sizestructure (26 feet high, 166 acre-feet).
d. Hazard Classification. Laguna Palma Dam is a high hazarddam. Downstream conditions indicate that loss of life is probableshould failure of the dam occur. Within the estimated damage zone
approximately three miles downstream of the dam are nine dwellings,county roads and Highway T.
e. Ownership. Laguna Palma Dam is owned by Harold Whitman.Correspondence should be addressed to:
Mr. Harold WhitmanRoute 1Desoto, Missouri 63020314-937-8377
f. Purpose of Dam. Laguna Palma Dam is used for recreation.
g. Design and Construction History. Based on interviewswith the owner Laguna Palma Dam was reportedly built in the
early 1940's. The present owner bought the dam in 1970. No
design drawings, reports or construction history exist.
h. Normal Operating Procedures. No operating records exist.
The drainline has not been operated by the present owner. Excess
inflow discharges over the spillway crest.
1. 3 PERTINEN T DATA
a. Drainage Area.
Laguna Palma Dam 7.07 square miles(U.S.G.S. quadrangle)
Lake Lackawanna Dam 2.30 square miles(U.S.G.S. quadrangle)
b. Discharge at Damsite (cfs).
(1) Maximum known flood at dam site Unknown(2) Spillway capacity at top of dam 1413(3) Drainlines Unknown
2
c. Elevation (feet) - Field survey based on spillway elevation
585 shown on U.S.G.S. quadrangle.
(1) Top of dam 588.7(2) Spillway crest 585.0(3) Normal pool 585.0(4) Maximum pool (PMF) 597.8(5) Invert on 24" CIP 579.0(6) Tailwater on day of inspection 569.0
(7) Streambed at centerline of dam 563.0
d. Reservoir (feet).
(1) Length of maximum pool (top of dam) 3000(2) Length of normal pool :200
e. Storage (acre-feet).
(1) Top of dam 166(2) Spillway crest 98(3) Normal pool 98(4) Maximum pool (PMF) 422
f. Reservoir Surface (acres).
(1) Top of dam 26(2) Spillway crest 16(3) Normal pool 16(4) Maximum pool (PMF) 36
g. Dam.
(1) Type Earth embankment with concretegravity spillway
(2) Length 530 feet(3) Height 26 feet(4) Top width - earth embankment 6 feet
- concrete gravity section 2.5 feet(5) Side slopes
Earth embankment - upstream Varies from 1.5H:lV to2.5H:lV
- downstream 3H:IVConcrete gravity section - upstream Unknown
- downstream lH:5V(6) Zoning None(7) Grout curtain None
h. Spillway.
(1) Type Concrete gravity-trapezoidal shape(2) Length 60 feet(3) Crest elevation 585(4) Upstream channel Lake
(5) Downstream channel West Fork(6) Weir shape Trapezoidal
3
A
i. Drawdown Facilities.
(1) Type 24" CIP(2) Elevation 579.0(3) Length 5.5 feet
(4) Closure Unknown
4
SECTION 2 - ENGINEERING DATA
2.1 DESIGN. No design drawings, reports or data are known toexist.
2.2 CONSTRUCTION. Based on interviews with the owner it isreported that the dam was constructed in the early 1940'. Noinformation exists on the construction the dam.
2.3 OPERATION. No operating records exist.
2.4 EVALUATION.
a. Availability. There are no engineering data available.
b. Adequacy. The field surveys and visual inspectionspresented herein are considered adequate to support the con-clusion of this report. Seepage and stability analyses comparableto the requirements of the guidelines are not on record. Thisis a deficiency which should be rectified.
c. Validity. Not applicable.
5
SECTION 3 - VISUAL INSPECTION
3.1 FNDINGS
a. General. The onsite inspection of Laguna Palma Damwas conducted by personnel of L. Robert Kimball and Associateson May 2, 1979. The inspection team consisted of a hydrologist,structural/soils engineer and a geologist. The inspectionconsisted of:
1. Visual inspection of the retaining structure, abutments,and toe.
2. Examaination of the spillway facilities, exposedportions of any outlet works, and other appurtenantworks.
3. Observations affecting the runoff potential of thedrainage basin.
b. Project Geology. The bedrock underlying Laguna PalmaLake consists primarily of the Roubidoux formation which ispart of the Canadian Series of the Ordovician System. TheGasconade formation underlies the Roubidoux formation and isalso exposed under part of the lake and probably the dam aswell.
The Roubidoux formation contains sandstone, dolomiticsandstone and cherty dolomite. Except in the central part ofthe state, the sandstone accounts for little more than 10% ofthe formation, the remainder consisting mostly of cherty dolomite.The dolomite is light gray to brown, finely crystalline, andthinly to thickly bedded. The Roubidoux formation ranges inthickness from 100 to 250 feet, but is probably thinner here,since much of it has been eroded away.
The Gasconade is primarly a light brownish-gray chertydolomite in this area. The lower part of the dolomite is coarselycrystalline and chert often makes up more than 50% of the volumeof the rock. The upper part of the dolomite, which is presentaround Laguna Palma, is finely crystalling and contains muchsmaller amounts of chert. The chert may be white and porcelain-like or with brown and gray bands. Many of the nearly verticalcliffs in the central Ozarks are formed by the Gasconade.Springs and caves are also common in this formation, which maybe from 300 to 700 feet thick.
Only one rock outcrop was observed during the inspection.This was at the right abutment of the dam and consisted ofcherty dolomite. This may be either the Upper Gasconade orthe lower Roubidoux. The rock was slightly weathered and exhibitedsome jointing while the beds were of moderate thickness. Solutioncavities are ofter found in these rock types, but no evidenceof karst terrain was observed in the vicinity. It is difficult
to distinguish any more detailed information on the basis ofone brief inspection with only one outcrop. The publishedliterature contains little else of value concerning theseto formations.
Structural features in the vicinity of Laguna Palma includethe Plattin Creek anticline, the axis of which passes the lakeimmediately to the west in a northeast-southwest direction.The axis plunges gently northwards. The eastern limb is slightlysteeper, but both limbs are reported as gentle (no dips aregiven). The Rugley School fault block and fault are anotherstructural feature lying two to three miles south of the lake.A component of the Valles Mines - Vineland fault zone which is,in turn, a part of the Ste. Genevieve fault system, the Rugleyschool fault is the largest of a series of faults bounding theRugley school fault block. This is an untilted wedge ofsediment marked by faults on the northwest, north and north-east. To the south, however, it merges with the Farmingtonanticline. The Rugley shcool fault brings the Davis Shaleinto contact with Gasconade Dolomite while the other faultshave small displacements of only about 75 feet. Some seismicactivity is still noted in this part of the state.
c. Dam and Spillway. Visual inspection of the dam indicatedthe structure was in fair condition. From a brief survey conductedduring the inspection, it was determined that a low point on thedam is at elevation 588.7 adjacent to the concrete gravity spill-way. The earth embankment section of the dam generally rises fromthe spillway section toward the left abutment. The earthembankment section is 440 feet long with a maximum height ofapproximately 15 feet. The upstream slope varies from l.5H:IV to2.5H:lV. The upstream slope of the dam is used as a boat dock.Small row boats and fishing craft are docked and pulled up on
the upstream slope of the dam. The crest width is a maximum ofapproximately 6 feet wide. The downstream slope is variable andaverages approximately 3H:lV. The downstream slope is grassed.No seepage or erosion was noted on the downstream slope at thetime of inspection.
The right abutment section of the dam is formed by a concretegravity section. This section is approximately 90 feet long ofwhich 60 feet acts as a spillway. The concrete wall extends tothe left of the spillway and forms part of the upstream slopeof the earth embankment for about 50 feet. The spillway istrapezoidal in shape. The concrete in this section was in fairto poor condition. The concrete is deteriorating and severallong diagonal cracks were noted on the downstream face. Thesediagonal cracks ran from near the spillway crest elevation tothe tailwater. Condition of the upstream portion of the concreteand earth section were not visible because of the lake level. Thedownstream portion of the concrete gravity section below thetailwater was unobserved.
7
The right abutment section of the dam is formed by a concretegravity section. This section is approximately 90 feet long ofwhich 60 feet acts as a spillway. The spillway is trapezoidal inshape. The concrete in this section was in fair to poor condition.The concrete is deteriorating and several long diagonal crackswere noted on the downstream face. These diagonal cracks ranfrom near the spillway crest elevation to the tailwater. Conditionof the upstream portion of the concrete and earth section were notvisible because of the lake level. The downstream portion of theconcrete gravity section below the tailwater was unobserved.
d. Drainlines. Approximately 6 feet below the spillwaycrest in the concrete gravity section is a 24" cast iron pipe.No controls were noted on the exposed downstream portion ofthis 24" cast iron pipe.
e. Reservoir Area. No pertinent problems were noted in thereservoir area. The watershed is moderately steep and wooded.Approximately 2 miles upstream of Laguna Palma Dam is an earthdam (Lake Lacawanna).
f. Downstream Channel. West Fork downstream of Laguna PalmaDam travels approximately 1000 feet before joining Plattin CreekPlattin Creek downstream of the dam has a moderately wide channel.
3.2 EVALUATION. The visual inspection did not reveal anyimmediate signs of instability. The earth embankment sectionof the dam appears to be in good condition. The concrete gravitysection appears to be in fair condition. Detailed examinationof the cracks in the concrete gravity section cannot be madewithout the reservoir level being dropped. The upstream conditionof these cracks if they extend through the dam was unobserved.In addition, with the water discharging over the spillway crest,it was impossible to determine whether any seepage zones exist inthe concrete section. Any undercutting of the toe was notdetermined because of the tailwater.
Complete evaluation of the structure cannot be made withouta detailed stability, stress or seepage analysis with tests ofconcrete or soil, mapping of the cracks and geometry of the concreteand earth embankment section.
8
SECTION 4 - OPERATIONAL PROCEDURES
4.1 PROCEDURES. The reservoir is maintained at the spillwaycrest. The reservoir has not been drawn down by the presentowner.
4.2 MAINTENANCE OF DAM. No maintenance of the dam is conducted.
4.3 MAINTENANCE OF OPERATING FACILITIES. The operating facilitiesare not maintained.
4.4 DESCRIPTION OF ANY WARNING SYSTEM IN EFFECT. Upon checkingwith the owner, the inspection team is unaware of any warningsystem in effect.
4.5 EVALUATION. Maintenance of the dam and-operating facilitiesare considered poor. There is no warning system in effect towarn downstream residences of large spillway discharges offailure of the dam.
9
SECTION 5 - HYDRAULIC/HYDROLOGIC
5.1 EVALUATION OF FEATURES
a. Design Data. There are no hydrualic and hydrologicaldesign data available as discussed in Section 2.
b. Experience Data. The drainage area was developedusing the U.S.G.S. quadrangle sheet. The lake surface areawas determined by planimetering the quadrangle sheet. Surfacearea - elevations were determined by planimetering variouscontour lines within the drainage area on the U.S.G.S. quad-rangle sheets. The spillway and dam layout was made from surveysconducted during the inspection. Despite no record of reservoirwater levels, there is no evidence or history of the dam beingovertopped.
c. Visual Observations. The spillway (60 feet long trapezoid)is located at the right abutment in the concrete gravity section.The right abutment is approximately 10 feet long and 1 foot higherthan the spillway crest elevation. This right abutment is formedfrom concrete and rock and can take overflow. Thus the top ofdam is considered 588.7 (left of the spillway). The earthportion of the dam cannot take overtopping for a long period oftime. The crest width is narrow and the embankment is formedfrom sandy clay with gravel. Approximately 2 miles upstream ofLaguna Palma Dam is an earth embankment approximately 40 feethigh (Lake Lacawanna). The spillway on Lake Lacawanna isapproximately 12 feet wide. Failure of Lake Lacawanna maycause overtopping and eventual failure of Laguna Palma Dam.The drainage area is wooded with gentle slopes and the soilcondition is considered to be fair regarding hydrologic conditions(hydrologic soil group B).
d. Overtopping Potential. Overtopping potential wasinvestigated through the development of the probable maximumflood (PMF) for the watershed and the subsequent routing ofthe PMF and fractions of the PMF through the reservoir andspillway.
The Corps of Engineers, St. Louis District, hasdirected that the HEC-l Dam Safety Version systemized computerprogram be utilized. The program was prepared by the HydraulicEngineering Center (HEC) U.S. Army Corp of Engineers, DavisCalifornia, July, 1978. The major methodologies or key inputdata for this program are discussed in Appendix B.
To enable us to complete the hydraulic and hydrologicanalysis for this structure, it was necessary to make thefollowing assumptions:
I. Top of dam was considered 588.7.
2. No flow through the drainline was considered.
3. The flood was routed through the upstream reservoir(Lake Lacawanna).
10
4. Failure of Lake Lacawanna was not considered.
Complete summary sheets of the computer output arepresented in Appendix B. To facilitate review, the majorresults of the overtopping analysis are presented below:
Peak Inflow 44157 cfsSpillway Capacity 1413 cfs
Ratio of Maximum Reservoir Maximum Depth Maximum DurationPMF Water Surface over Dam Outflow of over-
(embankment) cfs topping, hours
.10 590.42 1.72 4215 3.33
.50 594.39 5.69 22042 10.501.00 597.84 9.14 44364 13.83
The Corps of Engineers Spillway Design Flood for a highhazard-small dam is 1/2 PMF to the PMF. Based on the downstreamhazard exposure, the Spillway Design Flood for this dam is thePMF. The spillway is capable of controlling only approximately3% of the PMF without overtopping the embankment. Overtoppingthe embankment for an extended period of time or with depthwill cause failure of the dam. In addition, the upstream dam(Lake Lacawanna) can control only 2% of the P!tF without over-topping the embankment. If Lake Lacawanna should fail dueto overtopping an additional 152 acre-feet of water would besuddenly released and probable would cause failure of LagunaPalma.
Because of the low spillway capacity the 10 year stormwas routed through the reservoir. The spillway and reservoircan not control the 10 year storm. Despite no record ofreservoir water levels there is no evidence or history thatthe dam has been overtopped.
s . . . . ..
SECTION 6 - STRUCTURAL STABILITY
6.1 EVALUATION OF STRUCTURAL STABILITY
a. Visual Observations. Visual observations did notreveal any signs of immediate instability. The earth embankmentportion appeared to be in good condition. The slopes aremoderately flat and covered with grasses. No erosion or seepagewas noted on the embankment portion during the inspection.The concrete gravity section appeared to be in fair condition.The lake level and discharge through the spillwayprevented close observation of the downstream and upstreamslopes of the concrete gravity section. However, some deter-ioration of the concrete was noted. In addition, several longdiagonal cracks in the concrete were observed.
b. Design and Construction Data. No design or constructiondata is available on the dam. The dimensions of the dam cross-section are unknown. No testing of the concrete or earth embank-ment has been performed. Stability, stress and seepage analysescomparable to the requirements of the "Recommended Guidelinesfor Safety Inspections of Dams" were not available, which is
considered a deficiency.
c. Operating Records. No operating records are kept on thestructure.
d. Post Construction Changes. No post-construction changesare known for this structure.
e. Seismic Stability. The dam is located in seismic zone2, to which the guidelines assign a "moderate" damage potential.No seismic stability analysis has been conducted.
12
p -
SECTION 7 - ASSESSMIENT/EREDIAL MEASURES
7.1 DAM ASSESSMENT
a. Safety. The visual observations, review of availabledata, and hydrologic calculations indicate that Laguna PalmaDam's spillway is seriously inadequate. The spillway is capableof controlling approximately 3% of the PMF without overtoppingthe embankment. In addition, the spillway and reservoir cannot control the 10 year storm.
The earth embankment portion of the dam appeared tobe in good condition. No erosion or seepage zones were notedin the earth embankment section. The concrete gravity sectionappears to be in fair condition. Some deterioration of theconcrete and several long diagonal cracks were noted on thedownstream face. Water discharging over the downstream facemay have obscured some features. The high lake level preventedobservation of the upstream portions of the concrete gravitysection and the earth embankment section. The long term effectof the deterioration and weakening of the concrete is unknown.The concrete in the dam will deteriorate with age and shouldbe analyzed at periodic intervals. Stability, stress andseepage analyses comparable to the requirements of the "Rec-ommended Guidelines for Safety Inspections of Dams" were notavailable, which is considered a deficiency.
b. Adequacy of Information. Complete assessment of thestructural stability of the structure cannot be made becauseof the limited design data and construction data. Stability,stress and seepage analyses comparable to the requirement ofthe "Recommended Guidelines for Safety Inspections of Dams" werenot available, which is considered a deficiency.
c. Urgency. The deficiencies described herein are seriousand corrective actions listed below should be initiated immediately.Special note should be made of items listed in paragraph 7.2.a. andthese recommendations should be pursued on a high priority basis.
d. Need for Phase I. In order to accomplish some of therecommendations/remedial measures outlined below, further inves-tigations will be required.
7.2 RECOMMENDATIONS/REMEDIAL MEASURES
a. Alternatives. A detailed hydraulic and hydrology studyshould be conducted by a registered professional engineer know-ledgeable in dam design to increase the spillway capacity. Thestudy should be gin immediately and remedial modifications begunimmediately after the study is complete.
13
b. Operation and Maintenance Procedures. The followingoperation and maintenance procedures are recommended:
1. Stability, stress and seepage analyses should be con-ducted of the earth embankment portion of the concrete gravitysection by a registered professional engineer knowledgeable indam design.
2. Concrete samples of the concrete gravity section shouldbe obtained to determine the condition and strength of theconcrete.
3. The deteriorated concrete should be repaired.
4. Institute a formal inspection program to be conductedat regular intervals.
5. Institute a formal warning system to warn downstreamresidences of high spillway discharges or failure of the dam.
6. The drainline should be made operable. The drainlineshould be exercised and lubricated at six month intervals.
7. Riprap the upstream slope of the dam.
14
DRAWINGS
&I I -.
J'v
_ -J
;R \UT7 \ (.
" VICINITY WA
-I i- ~LAGUNA PALMA DAINISCALE lit -2000'FIGURE1
-ww
Ca, -
- 04
to
C,
0 00'1 1
HYDROLOGY AND HYDRAULICS
LL-2
APPENDIX B
HYDROLOGIC AND HYDRAULIC COMPUTATIONS
The hydrologic analysis used in development of the overtoppingpotential is based on applying a hypothetical storm to a unithydrograph to obtain the inflow hydrograph for a reservoir routing.The Probable Maximum Precipitation is derived and determined fromregional charts prepared by the National Weather Service in"Hydrometeorological Report No. 33." Reduction factors have notbeen applied. A 48 hour storm duration is assumed with totaldepth distributed over 6 hour periods in accordance withprocedures outlined in EH 1110-2-1411 (SPF Determination). Themaximum 6 hour rainfall period is then distributed to hourly incre-ments by the same criteria. Within-the-hour distribution isbased upon NOAA Technical Memorandum NWS HYDRO-35. The non-peak6 hour rainfall periods are distributed uniformly. All distributedvalues are arranged in a critical sequence by the SPF criteria.The final inflow hydrograph is produced by deduction of infil-tration losses appropriate to the soil, land use, and antecedentmoisture conditions.
The reservoir routing is accomplished by using ModifiedPuls routing techniques wherein the flood hydrograph is routedthrough lake storage. Hydraulic capacities of the outlet works,spillways, and crest of dam are used as outlet controls in therouting. Storage in the pool area is defined by an elevation-storage capacity curve. The hydraulic capacity of the outletworks, spillways, and top of dam are defined by elevation-discharge curves.
Dam overtopping analysis has been conducted by hydrologicmethods for this dam and lake. This computation determines thepercentage of the PMF hydrograph that the reservoir can containwithout the dam being overtopped. An output summary in thehydrologic appendix displays this information as well as othercharacteristics of the simulated dam overtopping.
The above analysis has been accomplished for this reportusing the systemized computer program HEC-l (Dam Safety Version),July, 1978, prepared by the Hydrologic Engineering Center, U.S.Army Corps of Engineers, Davis, California. The numeric para-meters estimated for this site are listed in the computer printout.Definitions of these variables are contained in the "User's Manual"for the computer program.
The inflow hydrograph was routed through the reservoir usingHEC-l's Modified Puls option.
B-I
DAMNAME P-\2~LMI> Ck PA
I.D. NUMBER 3 0+ 4-
L ROBERT KIMBALL & ASSOCIATES SEET O . _ _CONSULTING ENGINEERS & ARCHITECTS OF +
EBENSBURG PENNSYLVANIA BY OltJ DATE --
k~A.Nr -70- SQ, SM
LlNT c -4r H vo Ro 6.. .m ,,, ._ e .a
I *
=o."S WE-/{
Cul-.YE5 )iW\3L:EF M Jr oD.0
L_'-~,. C( _)'_______0 C __ '0 (zboQ' .-
(/0 I /o Ac ' -10 &-No 0 V v,, :,"S.,_0
.c.3 L 7 c S/o .r J ex ' , Cc.J
R T I c;R " p.,5
B-2
K 7/1 D~~~~~~~~AM NAME. J '
. ,,. , .v
1.0. NUMBER 2FO C 4-
L. ROBERT KIMBALL & ASSOCIATESCT CONSULTING ENGINEERS & ARCHITECTS SHEETNO." ".- -.-OF
, EBENSBURG PENNSYLVANIA BY 0" DATE °
--
/a
Wrzom• /..z. l . 3
'__- V' Co -c <:c _ = ,- 4T' L..Tc-. .Ftc~ cN ME0 A. 0 ON'E -7 Z Yc Lo
RIFT
..k.C ' C- 7-_ A,
S, , C, R Sr I
L 5. 4-1kc)
Ov~i.- N PP'c MP1E -rA Y 0
1.i4 . -s \/ 1A =~( -5 A-A-1c i--r /. 2
+II
B-3
DAM NAME L 2 .- h4-
L. ROBERT KIMBALL & ASSOCIATES .. NUMBER
C2 CONSULTING ENGINEERS & ARCHITECTS SHEET NO. -_OF "
= EBENSBURG PENNSYLVANIA BY 0 72 DATE - " --
S~ L W . kit (h, Iv [N'. GC C- LJ
'.51
0h' .5 A3(0,7
b I
z:/ v o
59T.5
58G.6
59-7 a
.588. o.535
588.5 ,a589 45?. 5 Z2so
59) -5080~
59 4 99o
/0
Yks.%jEz 1umo6o 1'o N8.5.Lr. ; /0 rso
B-4
5 .( -~
DAM NAME -
1.0. NUMBERL . ROBERT KIMBALL & ASSOCIATES
C7 CONSULTING ENGINEERS &ARCHITECTS SHEET NO..........OFEBENSBURG PENNSYLVANIA BY 02'. DATE
zue4 0 kj .
B-5
I. 10
CLL 0
0 IK
0
aca
99 44
44 0- a P w i
aJ 4 r- 4
04Nus0 oanid W' cv a CI r-
C-
id.1
4 0 4 w4 de4
O* 0-
-0!! At
00 -0
C4
co ** 0
o A
4L *31"- U .9Va
4 fa do @
a - 41 .
1- 0 -C4 * P*aw t- a p 0 0UL .0% o. ik 0.f !.
0 4 .44 40 V* E
A 4A
.... ...
CC I
IIfI IL
0 > lac
-C 40 ku -
9-
-j -1 0CL CL".%
As V CL a
or A
Cie 0.
uccc
me--
x IL .-
u~B-8
'In
10Lo a
0 0
ewIK
o a 4
0 t" us
I 00oc
401
0 6
cc) m4 Z
a- C4 As-a
0 re ea a
a. * B.9
'AAn
at 0P
ata
10 0
dc 23c 0c
3 9
64 a
o1 a
* a
-9 a
%0 '-
U, U.N
P1'
4
-O S.
0. 4M *
Wo-
-41
cc xv fq
ID a. -4b
k2 0
-A*
%A 0
oo 4;
1" 4 *3-
a3 4
ii Li
IV
al In 0.- Q
0 wo w ,a- u10a. - (2
o 0 0 s- _O ~0
4 a
w 0%
-. - .Inin.
eq 4n
2 0 0.
fm0do* S
0 0 0 %D .
o q -
0 - '* -30'
a in
00in 010 0 P.0 *
I-C~o 4f444 .
0J ii .. -4 aF.
0 . -1 0 n
CI 0
IJ Ic _ I . cc
44
4-- .ja
lAIn
v P- 4
4 O*~~v I 0
IC .
wo W"
of D. &C *. k 0*~c 40i 4 C
CC dc 9-0 ££ £ U
J 0I B. CL1
m ~ 4 VO~
0 0U 11.
z. ' 4
14 -C fa U -de .J 1.4-
a cc
14.B0 14
on an 0
00 0
0 a
IIn
- 0 C 0
a~ 0 0
- a 0 A 0 at 0
- * a 0a C - :
. 0 . 4e--I-- 40 * g*
- P P- e w in .to 0 a.
V- 0 0
a.4 0 O4,
p. . -15 4. g
J a
4n 0
in .
04
AL 20 a4 A 6
4 *l
319 bdai * i
IL 06
0.. B- .9
i i0j
m z aA a t a .- a - 0- ft
0- ~ .24in i
90 IC wk 0 4 t f
w .h
cc 64% 04 0 * P' V
0lU.4 N Uf4 a
-4 4
4 I - - - -
39 1
oo
ft 'no. NI~ 'no4 - z -Z
A:s; N. v
4K -
af me i84
ccC
mobs
0000
!qc~ 008
C::44c t-
x 4 0
%9 .J 4p
4c -_j M O P.
cc > 0 0 0 .O@
uo 0 . 0
;OZ- I.
I i
z-. 00
L0. o
0
61) 0*
0Q0
inA 0 ine4r
us 0 P%~ ~
tooIt 4 .
0 I
s-UA;a s-
0
19
5*550 .. . .
0..) OA
*0B-11
PHOTOGRAPHS
Photos 6 and 7 Upstream Dam(Lake Locawonno)
P5
P-INDICATES PHOTO LOCATION LAGUNA PALMA DAMPHOTO INDEX
C-1
~t4
Photograph No. 1
Spillway.
C-2
Photograph No. 2
Upstream slope of earth embankment section.Note concrete wall in foreground.
Photograph No. 3
Upstream slope of earth embankment section.
C-3
Photograph No. 4
Earth embankment.
4-
Photograph No. 5
Downstream slope of earth embankment.
C-4
Photograph No. 6
Lake Lacawanna.
Photograph No. 7
Lake Lacawanna spillway.
C-5
