FORT COBB RESERVOIR

1993 SEDIMENTATION SURVEY

U.S. Department of the Interior

Bureau of Reclamation
7-2090 (4-81)

,f TECHNICAL REPORT STANDARD TITLE PAGE

- 1 REPORT NO 3 RECIPIENTS CATALOG NO

4. TITLE AND SUBTITLE 5. REPORT DATE

May 1994

Fort Cobb Reservoir 6. PERFORMING ORGANIZATION CODE

1993 Sedimentation Survey

D-5753

7. AUTHOR(S) 8. PERFORMING ORGANIZATION

Ronald L. Ferrari REPORT NO.

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. WORK UNIT NO.

Bureau of Reclamation 11. CONTRACT OR GRANT NO.

Denver Office

Denver CO 80225 13. TYPE OF REPORT AND PERIOD COVERED

12. SPONSORING AGENCY NAME AND ADDRESS

DIBR

Same

14. SPONSORING AGENCY CODE

D-5753

15. SUPPLEMENTARY NOTES

Microfiche and hard copy available at the Denver Office, Denver, Colorado

16. ABSTRACT

The Bureau of Reclamation completed a survey of Fort Cobb Reservoir in the spring of 1993.

The survey report presents the results of an investigation to monitor changes caused by

sediment accumulation in Fort Cobb Reservoir after 34.0 years of reservoir operation. The

report also describes the surveying procedures and equipment used in the 1993 investigation

and provides data for future surveys. The primary purpose of the 1993 survey was the

collection of data to compute the area-capacity relationships for operation of Fort Cobb

Reservoir.

As of April 1993, the survey determined that the reservoir has a storage capacity of 135,898

acre-feet and a surface area of 5,882 acres at spillway crest elevation 1354.8. Since closure in

March 1959, the reservoir has accumulated a volume of 6,966 acre-feet of sediment below

spiliway crest elevation 1354.8. This volume represents a 4.88-percent loss in total capacity

and an average annual loss of 204.9 acre-feet for the operation period of March 1959 through

May 1993.

17. KEY WORDS AND DOCUMENT ANALYSIS

a. DESCRIPTORS-- reservoir area and capacity! sedimentation! reservoir surveys! sonar!

sediment distribution! contour area! reservoir area! sedimentation survey!

b. IDENTIFIERS- Fort Cobb Reservoir! Oklahoma-Texas Projects Office! Fort Cobb Reservoir

Master Conservancy DistrictJ

c. COSATI Field/Group 13/B COWRR: 1302.66 SRIM:

18. DISTRIBUTION STATEMENT 19. SECURITY CLASS 21. NO. OF PAGES

HIS REPORT) 33 UNCLASSIF!ED

20. SECURITY CLASS 22. PRICE

(THIS PAGE)

UNCLASSIFIED
FORT COBB RESERVOIR

1993 SEDIMENTATION SURVEY

by

Ronald L. Ferrari

Sedimentation Section

Surface Water Branch

Division of Earth Sciences

Denver Office

Denver, Colorado

May 1994
ACKNOWLEDGMENTS

The Bureau of Reclamation's Sedimentation Section prepared

and published this report. The hydrographic survey was

supervised by Ronald Ferrari, Hydraulic Engineer, and assisted

by Charles Feuerboun and Carol Newcomb of the OklahomaTexas Projects Office and personnel from the FCRMCD (Fort

Cobb Reservoir Master Conservancy District of Anadarko,

Oklahoma). The preliminary field work of locating and flagging

the existing sediment range end markers and surveying the

above-water portions of the sediment range lines was performed

by Charles Feuerboun and Carol Newcomb of the OklahomaTexas Projects Office and personnel from the FCRMCD. Ronald

Ferrari completed the data processing, sediment computations,

area-capacity tables, and the report. Gerald Schultz assisted in

the processing of the coflected range line data.

U.S. Department of the Interior

Mission Statement

As the Nation's principal conservation agency, the Department of the

Interior has responsibility for most of our nationally-owned public

lands and natural resources. This includes fostering sound use of our

land and water resources; protecting our fish, wildlife, and biological

diversity; preserving the environmental and cultural values of our

national parks and histhrical places; and providing for the enjoyment

of life through outdoor recreation. The Department assesses our

energy and mineral resources and works to ensure that their

development is in the best interests of all our people by encouraging

stewardship and citizen participation in their care. The Department

also has a major responsibility for American Indian reservation

communities and for people who live in island territories under U.S.

administration.

The information contained in this report regarding commercial

products or firms may not be used for advertising or promotional

purposes and is not to be construed as an endorsement of any

product or firm by the Bureau of Reclamation.

The information contained in this report was developed for the

Bureau of Reclamation; no warranty as to the accuracy,

usefulness, or completeness is expressed or implied.

11
CONTENTS

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Page

Introduction 1

Summary and conclusions 2

Surveys 2

Survey history 2

1993 resurvey 2

Reservoir area and capacity 3

Development of 1993 contour areas 3

1993 revised storage capacity 4

Sediment analyses 4

Sedimentation accumulation 4

Sedimentation summary 5

Reservoir sediment distribution 5

Longitudinal distribution 5

Lateral distribution 5

References 6

TABLES

Table

1 Reservoir sediment data summary (page 1 of 2) 7

1 Reservoir sediment data summary (page 2 of 2) 8

2 Summary of 1993 survey results 9

3 Segmented reservoir areas 10

FIGURES

Figure

1 Fort Cobb Reservoir location map 11

2 Fort Cobb Dam, plan and section 12

3 Fort Cobb Reservoir range location map 13

4 Width adjustment method for revising contour areas 15

5 Area and capacity curves - Fort Cobb Reservoir 16

6 Longitudinal profile - Pond (Cobb) Creek 17

7 Longitudinal profile - Willow Creek 18

8 Sediment Range 1 - Pond Creek 19

9 Sediment Range 2 - Pond Creek 20

10 Sediment Range 3 - Pond Creek 21

11 Sediment Range 4 - Pond Creek 22

12 Sediment Range 5 - Pond Creek 23

13 Sediment Range 6 - Pond Creek 24

14 Sediment Range 7 - Pond Creek 25

15 Sediment Range 8 - Pond Creek 26

16 Sediment Range 20 - Willow Creek 27

17 Sediment Range 21 - Willow Creek 28

18 Sediment Range 22 - Willow Creek 29

19 Sediment Range 23 - Willow Creek 30

20 Sediment Range 30 - Lake Creek 31

21 Sediment Range 31 - Lake Creek 32

22 Sediment Range 40 - Camp Creek 33

111

INTRODUCTION

Fort Cobb Dam and Reservoir are major features of the Washita Basin Projects in

southwestern Oklahoma. Other principal features are Foss Dam and Reservoir. The project

supplies municipal and industrial water and provides flood control, fish and wildlife, and

recreation benefits.

Fort Cobb Dam and reservoir are located in Caddo County, about 22 miles northwest of

Anadarko and 5 miles north of Fort Cobb, Oklahoma. The dam is on Pond (Cobb) Creek,

roughly 5 miles above the confluence of Cobb Creek with the Washita River (fig. 1). The dam

and reservoir are operated by the FCRMCD (Fort Cobb Reservoir Master Conservancy

District).

Fort Cobb Dam was constructed during 1958 and 1959, and storage began on March 30, 1959.

The conservation pool filled in June 1962, which is when normal operation began. The dam

(fig. 2) is a nearly homogeneous, rolled earthflll structure 122 feet above the Pond Creek

streambed. The dam crest has a maximum elevation of 1,380 feet mean sea level, a crest

length of 9,900 feet, and a crest width of 30 feet.

The spiliway is an ungated morning-glory type located on the left abutment and has a

capacity of 3,050 cubic feet per second at a water surface elevation of 1374.4 feet. A concrete

inlet feeds into a 9.5-foot-diameter concrete conduit which passes through the abutment. The

conduit empties into a concrete chute which feeds a stilling basin downstream from the dam.

The outlet works consists of a river outlet works (with a capacity of 2,570 cubic feet per

second at water surface elevation 1374.4) and an adjacent municipal outlet works on the right

abutment. The river outlet works, which has a crest elevation of 1300 feet, has a concrete

intake structure fitted with trashracks. The intake structure feeds into a 9.0-foot-diameter

concrete conduit which leads through the abutment to a gate chamber located about 60 feet

upstream from centerline. The gate chamber contains two high-pressure regulating gates and

two emergency gates which control flow into a concrete conduit which passes through the

downstream portion of the dam into a concrete chute and stilling basin.

The upstream portion of the municipal outlet works consists of two 26-inch-diameter steel

pipes encased in concrete which lead from the river outlet works intake structure to the

above-mentioned gate chamber. The gate chamber contains two gate valves which control

flow into a 26-inch-diameter steel pipe passing through the downstream portion of the dam.

The steel pipe, contained in a 7.0-foot-high by 5.2-foot-wide concrete adit, continues through

the control house at the dam toe to a stilling well at the intake of the Anadarko aqueduct.

The reservoir length is 12.5 miles, summation of Pond, Wifiow, and Lake Creeks, and has an

average width of 0.51 miles at reservoir pool elevation 1342.0. Average width is determined

by dividing the surface area by the reservoir length at elevation 1342.0. Total drainage area

above the dam is 317 square miles, of which 262 square miles contributes sediment inflow.

The sediment contributing area is the total drainage area minus 51 square miles as identified

by the Bureau of Reclamation as probably noncontributing during a 1956 flood study.

* The definition of terms such as "structural height," 'hydraulic height," etc., may be found in manuals such as

Reclamation's Design of Small Dams and Guide for Preparation of Standing Operating Procedures for Dams and

Reservoirs, or ASCE's Nomenclature for Hydraulics.
At the beginning of reservoir storage in March 1959, Fort Cobb Reservoir had a calculated

surface area of 5,915 acres and a capacity of 143,740 acre-feet at elevation 1354.8.

SUMMARY AND CONCLUSIONS

This report presents the results of an investigation to monitor changes caused by sediment

accumulations in Fort Cobb Reservoir after 34.0 years of reservoir operations. The report

also describes the surveying procedures and equipment used in the 1993 investigation and

provides data for future surveys. The primary purpose of the 1993 survey was the collection

of data to compute the area-capacity relationships for operation of Fort Cobb Reservoir.

Tables 1 and 2 contain a summary of reservoir sediment data for the 1993 survey. The 1993

survey determined that the reservoir has a storage capacity of 135,898 acre-feet and a surface

area of 5,882 acres at spiiway crest elevation 1354.8. Since closure in March 1959, the

reservoir has accumulated a volume of 6,966 acre-feet of sediment below elevation 1354.8.

This volume represents a 4.88-percent loss in total capacity and an average annual loss of

204.9 acre-feet for the operation period of March 1959 through April 1993.

SURVEYS

Survey History

The original sediment ranges were surveyed by the Bureau of Reclamation prior to

inundation of water behind Fort Cobb Reservoir dam and are referred to as the original, or

1959, data. Figure 3 illustrates the range line network for Fort Cobb Reservoir. The original

surface areas for Fort Cobb Reservoir were determined by planimetering topographic maps

of the reservoir area developed prior to inundation. The reservoir topography consists of 28

maps (No. 853-500-16 through 853-500-43) with a scale of 1 inch equals 400 feet and 5-foot

contour intervals.

1993 Resurvey

The preliminary field work of locating and flagging the existing sediment range end markers

and surveying the above-water portions of the sediment range lines was performed by the

Oklahoma-Texas Projects Office and FCRMCD. The hydrographic survey was performed

from March 31 through April 2, 1993 (reservoir elevation 1341.88 through 1342.08), using

Reclamation's small boat bathymetric survey system. The small boat system consisted of a

sonic depth recorder and reflector prism mounted on the boat. The distances from a known

point, usually one of the range end markers, to the small boat were determined as the boat

proceeded along the range line by an EDM (electronic distance measuring) instrument set up

on shore aimed at the mounted reflector target. Range distances were communicated, by

radio, from shore to the boat at preselected intervals and marked on the sonar charts as the

boat proceeded across the reservoir. The boat was held on course as closely as possible by

radio communication from the EDM operator to the survey boat. This system was used to

collect the data for range lines 1 through 6, 20, and 21. The rest of the range lines were

located above water and collected by the Oklahoma-Texas Projects Office using standard

surveying procedures.

2
RESERVOIR AREA AND CAPACITY

Development of 1993 Contour Areas

For the purposes of the 1993 sedimentation analysis and to better represent storage changes,

the reservoir was subdivided into segments using the range lines to delineate the limit of

each segmental boundary. The segmental surface areas of the 5-foot contours for elevations

1280.0 through 1375.0 were digitized and summarized to determine the original reservoir

surface areas. This method was used to determine the original surface area of the reservoir,

but the resulting segmented areas could not be located for the 1993 study. For the 1993

analysis the Reclamation Service Center redigitized the segmental areas of the 5-foot

contours using microfilmed copies of the original 1 inch equals 400 feet topographic maps.

The total segmented areas for the digitized 5-foot contours compared fairly well with the

original areas and required only minor adjustments to match the original total areas. Table

3 gives a summary of the areas by segments and elevations.

The 1993 reservoir surface areas were computed by the width adjustment method described

by Blanton (1982) and illustrated on figure 4. The method entails computing the new

segmented contour area,A1, between any two ranges by applying an adjustment factor to the

original segmental contour area, A0. The computed adjustment factor for each segment was

the ratio of the new average width to the original average width for both the upstream and

downstream ranges at the specified contour elevation. These calculations were completed by

Reclamation's computer program RESSED. The input data included the original and 1993

range line data along with the segmented areas for the specified contour elevation. The

program computes the 1993 surface area for each segment at the given contour elevations.

A comparison of simultaneous plots of original and 1993 range profiles indicated the lateral

distribution of sediment at the different measured contour elevations. Where these plots

indicate changes have occurred on the side slopes of the reservoir, a decision was made to

determine whether the change was caused by survey inaccuracies or actual deposition or

erosion. The adjustment factor was set to 1.0 if the measured change was judged to be

caused by survey inaccuracy. Additional modifications to the calculated width adjustment

factor were done to better represent the contour surface area changes. Because the original

topography of Fort Cobb Reservoir had only 5-foot contours, obtaining a better representation

of the sediment surface areas was deemed necessary. These sediment surface areas were

developed by calculating the 1993 average bottom profile versus the original thalweg profile

and transferring the location of the 1993 contour crossing to the original topography, and

digitizing the resulting sediment surface areas. This procedure was done for the contour

crossings that terminated within a segment.

The RESSED program output listed the revised areas for each segment and noted where

judgement led to overriding the adjustment factors, The output also noted where the

adjustment factors were overridden to reflect the digitized surface areas of the contours that

terminated within the segments. The 1993 total reservoir surface area at a given contour

was the summation of all segmental areas at that elevation. The 1993 total area computation

results are listed in column 4 of table 2.
1993 Revised Storage Capacity

The storage-elevation relationships based on the 1993 underwater survey data were

developed using Reclamation's area-capacity computer program ACAP (Reclamation, 1985).

The 1993 surface areas resulting from the RESSED computations at 5-foot contour intervals

from elevation 1290.0 through 1375.0 were used as the control parameters for computing

reservoir capacity. The 1993 study only surveyed ranges that measured changes from

contour elevations 1280.0 through 1370.0. The original surface area for the 1375.0 contour

was used for capacity calculations because it was judged that the reservoir has not affected

this contour area. The program computes an area at 0.01- to 1.0-foot area increments by

linear interpolation between the given contour intervals. The program begins by testing the

initial capacity equation over successive intervals to ensure that the equation fits within an

allowable error limit, which was set at 0.00000 1 for Fort Cobb Reservoir. This capacity

equation is then used over the full range of intervals fitting within this allowable error limit.

For the first interval at which the initial allowable error limit is exceeded, a new capacity

equation (integrated from the basic area curve over that interval) begins testing the fit until

it also exceeds the error limit. Thus, the capacity curve is defmed by a series of curves, each

fitting a certain region of data. Final area equations are derived by differentiating the

capacity equations, which are of second order polynomial form:

y = a + a2x + a,x2

where:

y capacity,

x = elevation above a reference base,

a intercept, and

a2 and a3 = coefficients

Results of the 1993 Fort Cobb Reservoir area and capacity computations are listed in tables

1 and 2 and plotted on figure 5. A separate set of 1993 area and capacity tables was

published for the 0.01-, 0.1-, and 1-foot elevation increments. The 1993 area and capacity

computations results are listed in columns (4) and (5) of table 2. Column 2 in the table gives

the original measured contour areas used in the original area and capacity computation, and

column 3 gives the original capacity recomputed using ACAP. Both the original and 1993

area and capacity curves are plotted on figure 5 for a visual comparison of changes. The 1993

survey determined that the reservoir has a storage capacity of 135,898 acre-feet and a surface

area of 5,882 acres at spillway crest elevation 1354.8.

SEDIMENT ANALYSES

Sedimentation Accumulation

Since storage began in March 1959, sediments have accumulated in Fort Cobb Reservoir to

a estimated volume of 6,966 acre-feet below the spillway crest elevation of 1354.8. This

volume represents a 4.88-percent loss in total capacity and an average annual accumulation

rate of 204.9 acre-feet for the 34.0-year period of operation. The net sediment accumulation

rate from the contributing basin was 0.782 acre-feet per square mile per year for the same

period.

4
Sedimentation Summary

The results of the sediment data and volume computations for the 1993 survey are shown in

table 1 and table 2. The data include a tabulation of incremental sediment inflow volume

and sediment accumulation computed for the period between initial conditions and the 1993

resurvey. Table 1 includes information on the drainage basin, records of estimated inflow,

reservoir operations, and reservoir storage.

RESERVOIR SEDIMENT DISTRIBUTION

Longitudinal Distribution

The distribution of sediment throughout the length of the reservoir is illustrated by plots of

the thaiweg profile representing the original and 1993 resurveyed profiles for the Pond and

Willow Creeks as shown on figures 6 and 7. Thalweg elevations representing original and

the resurveyed reservoir conditions were taken from the 1993 survey notes and large scale

plots of the original range line data. Except for the possibility of some missed low points, the

plotted profile should closely resemble actual channel bottom conditions during the original

range survey completed prior to inundation of the reservoir. Except for some minor

inaccuracies in sounding and being slightly off line, the bottom of the 1993 profiles should

closely represent channel bottom conditions at the time of those resurveys. The channel

distance used for range line location is the original river channel distance from the dam to

each range line in an upstream direction on Pond Creek and from the confluence to each

range line in an upstream direction on Willow Creek.

Lateral Distribution

The original survey notes or coordinate data were not available, so for this study, the original

range line data were determined by scaling off break points from plots of the original range

lines. Plan and profile plots of 23 original Fort Cobb range lines were available on

Reclamation Drawing Numbers 853-522-95 through 853-522-117. Ground profiles for the

original surveyed sediment ranges are shown on figures 8 through 22. The 1993 range profile

data are superimposed on these plots to indicate the changes which have occurred and to

represent in general the lateral distribution of sediment within the reservoir from elevation

1375.0 and below. Modification to the 1993 data included shifting stations slightly to better

align features. For sediment computation purposes, a complete section was needed for all

ranges. For this reason, the original data were inserted into the 1993 data ifie to complete

the areas not surveyed in 1993.

5
REFERENCES

American Society of Civil Engineers, Nomenclature for Hydraulics, ASCE Headquarters, New

York, 1962,

Blanton, J.O. III, "Procedures for Monitoring Reservoir Sedimentation: Technical Guideline

for Bureau of Reclamation," Denver Office, Denver, CO, October 1982.

Bureau of Reclamation, Project Data, Denver Office, Denver, CO, 1981.

Bureau of Reclamation, Surface Water Branch, ACAP85 User's Manual, Denver Office,

Denver, Colorado, 1985.

Bureau of Reclamation, Guide for Preparation of Standing Operating Procedures for Bureau

of Reclamation Dams and Reservoirs, U.S. Government Printing Office, Denver, CO, 1987a.

Bureau of Reclamation, Design of Small Dams, U.S. Government Printing Office, Denver, CO,

198Th.

Bureau of Reclamation, Fort Cobb Reservoir Area and Capacity Tables, Washita Basin

Project, Great Plains Region, Denver, CO, April 1993.

Kansas Geological Survey, SURFACE II GRAPHICS SYSTEM, Lawrence, Kansas, 1978.

6
RESERVOIR SEDIMENT

DATA SUMMARY Fort Cobb Reservoir

NAME OF RESERVOIR 1

DATA SHEET NO.

D 1. OWNER Bureau of Reclamation 2. STREAM Pond (Cobb) Creek 3. STATE Oklahoma

A 4. SEC. 22 TWP. 8N RANGE 12W 5. NEAREST P.O. Fort Cobb 6. COUNTY Caddo

M 7. LAT 35° 09' 58 LONG 98° 27' 23 8. TOP OF DAM ELEVATION 1380 9. SPILLWAY CREST EL. 1354.8'

R 10. STORAGE 11. ELEVATI ON 2. ORIGINAL 13. ORIGINAL 4. GROSS STORAGE 15. DATE

E ALLOCATION TOP OF P'X'L SURFACE AREA, Ac CAPACITY, AF ACRE- FEET STORAGE

BEGAN

a. SURCHARGE 1374.4 9,422 148,650 292,390

R b. FLcXJD CONTROL 1354.8 5,915 63,730 143,740

V 3/30/59

c. POWER

I d. WATER SUPPLY 16. DATE

F

a. IRRIGATION

NORMAL

OPERATION

f. CONSERVATION 1342.0 4,070 78,346 80,010 BEGAN

g. INACTIVE 1300.0 340 1,664 1,644 6/1962

17. LENGTH OF RESEhOIR 12.5' MILES AVG. WIDTH OF RESERVOIR 0.51 MILES

'F i. TOTAL DRAINAGE AREA 1171 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 23 INCHES

19. NET SEDIMENT CONTRIBUTING AREA 262 SQUARE MILES 23. MEAN ANNUAL RUNOFF 2.47 INCHES

I 20. LENGTH MILES AV . WIDTH MILES 24. MEAN ANNUAL RUNOFF 41,708° ACRE-FEET

N

21. MAX. ELEVATION 1764 MIH. ELEVATION 1300 25. ANNUAL TEMP. MEAN 60°F° RANGE 120°F to 15°F°

26. DATE OF 27. 28. 29. TYPE OF 30. NO. u8 31. SURFACE 32. CAPACITY 33. C/I

U SURVEY PER. ACCL. SURVEY RANGES OR AREA, AC. ACRE-FEET RATIO AF/AF

R YRS. YRS. INTERVAL

3/30/59 Contour (D) 5-ft 5,915' 142,864' 3.42

y (9,422)8 (291,432)8 6.99

4/2/93 34.0 34.0 Range ID) 15 5,882° 135,898° 3.26

(9,421) (284,079) 6.81

T 26. DATE OF 34. PERIOD 35. PERIOD WATER INFLOW, ACRE FEET WATER INFLOW TO DATE, AF

A SURVEY ANNUAL

PRECIP.

a. MEAN ANN. b. MAX. ANN. c. TOTAL a. MEAN ANN. b. TOTAL

4/93 23 41,7086 130,6656 1,418,069° 41,7086 1,418,0696

26. DATE OF 37. PERIOD CAPACITY LOSS, ACRE-FEET 38. TOTAL SEDIMENT DEPOSITS TO DATE, AF

SURVEY

a. TOTAL b. AV. ANN. c. /MI.'-YR. a. TOTAL b. AV. ANNUAL c. /MI.'-YR.

4/93 6,966 204.9 0.782 6,966 204.9 0.782

(7,353) (216.3) (0.825) (7,353) (216.3) (0.825)

26. DATE OF 39. AV. DRY 40. SED. DEP. TONS/MI.'-YR. 41. STORAGE LOSS, PCT. 42. SEDIMENT

SURVEY MT. )#/FT3) INFLOW, PPM

a. PERIOD b. TOTAL TO a. AV. b. TOTAL TO a. b.

DATE ANNUAL DATE PER. TOT.

4/93 0.14310 4.8800

(0.074) (2.52)

26.

DATE

43. DEPTH DESIGNATION RANGE IN FEET BELOW, AND ABOVE, CREST ELEVATION 1354.8

OF

SURVEY

72.8

59.8

- 59.8

49.8

- 49

39

.8-

.8

39.8-

24.8

29.8-

24.8

24.8-

19.8

19.8-

14.8

14.8-

9.8

9.8-

CREST

CREST-

+19.6

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

4/93 4.3 4.4 3.9 7.8 10.3 14.6 21.5 19.2 8.7 5.3

26. 44. REACH DES IGNATION PERCENT OF TOTAL ORIG INAL LENGTH OF RESERVOIR

DATE

SURVEY

0-10 10-

20

20-

30

30-

40

40-

50

50-

60

60-

70

70-

80

80-

90

90-

100

100-

105

105-

110

110-

115

115-

120

120-

125

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

N/A

Tab'e 1. - Reservoir sediment data summary (page 1 of 2).

7
45. RANGE IN RESERVOIR OPERATION

WATER YEAR MAX. ELEV. " WIN. ELEV.'1 INFLOW, AR YEAR MAX. ELEV. WIN. ELEV. INFLOW, AR

1959 1318.6 1279.0 10,603 1960 1330.3 1323.1 30,026

1961 1338.1 1332.6 25,980 1962 1338.5 1342.1 19,962

1963 1342.2 1340.7 14,955 1964 1342.2 1340.7 10,608

1965 1345.3 1340.6 46,263 1966 1342.2 1341.1 16,347

1967 1342.0 1340.3 10,994 1968 1342.5 1340.2 27,968

1969 1342.2 1340.2 32,838 1970 1340.7 1338.8 21,826

1971 1338.5 1337.2 22,274 1972 1338.8 1335.5 19,550

1973 1342.0 1335.2 46,769 1974 1343.2 1341.4 37,236

1975 1344.5 1341.2 72,135 1976 1343.1 1340.3 30,922

1977 1346.7 1340.3 50,618 1978 1342.8 1339.8 28,321

1979 1341.3 1338.9 24,758 1980 1342.1 1338.4 40,497

1981 1339.4 1337.2 21,196 1982 1349.3 1337.2 72,399

1983 1342.9 1340.2 27,391 1984 1343.3 1338.0 33,784

1985 1340.0 1337.4 25,539 1986 1346.6 3338.1 62,679

1987 1349.1 1342.0 114,578 1988 1343.6 1340.5 59,932

1989 1343.9 1341.3 72,351 1990 1344.4 1341.8 130,665

1991 1342.8 1341.4 46,043 1992 1342.5 1341.8 60,151

______________

3342.7 1341.6 49,921 ______________ _______________ ______________

46. ELEVATI

_

Om - AREA - CAPACITY DATA ROR O OflAL CAPACX'l

______________

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

1279 0 0 1280 1 0 1285 11 30

1290 30 133 1295 133 540 1300 350 1,748

1305 557 4,015 1310 872 7,588 1315 1,169 12,690

1320 1,548 19,483 1325 2,013 28,385 1330 2,516 39,708

1335 3,175 53,935 1340 3,844 71,483 1342 4,109 79,436

1345 4,506 92,358 1350 5,111 116,400 1354.8 5,915 142,864

1355 5,949 144,050 1360 6,728 175,743 1365 7,623 211,620

1370 8,516 251,968 1375 9,546 297,323

____________ _____________ _____________

46. ELEVATfUN - AREA - CAPACIT? DATA OR 1993 ckPA,.. ...'lY ___________ __________

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

1290 - 0 0 1295 90.4 226 1300 323.1 1,260

1305 524.4 3,378 1310 848.3 6,810 1315 1,132.1 11,761

1320 1,513.9 18,376 1325 1,890.8 26,888 1330 2,334.5 37,451

1335 2,926.5 50,604 1340 3,459.0 66,567 1342 3,806 73,833

1345 4,327.5 86,034 1350 5,087.6 109,571 1354.8 5,882 135,898

1355 5,915 137,078 1360 6,704 168,625 1365 7,602.3 204,391

1370 8,501.3 244,650 1374.4 9,421 284,079 _____________

47. REMARKS AND REFERENCES

Crest elevation of morning-glory inlet structure with ungated crest.

2 Total le ngth includes Pond (Cobb) Creek, Willow Creek and Lake Creek at e levation 1342.0 .

Bureau o f Reclamation 1956 flood study measured total drainage area above Fork Cobb Dam as 317 square miles with

portions totaling 51 s quare miles as considered noncontributing.

Bureau o f Reclamation Project Data Book, 1981.

Calculat ed from mean annual runoff value, 41,708 acre-feet, Item 24.

6 unregula ted monthly i nflow records for water years April 1959 through Apr il 1993.

Surface area and capacity at elevation 1354.8, spillway crest. Area and capacity recalc ulated to conform to

current computational methods using Bureau of Reclamation program ACAP.

All valu es enclosed i n parentheses are maximum water surface values at el evation 1374.4.

Surface area and capacity at elevation 1354.8, spillway crest. Area and capacity calcul ated by Bureau of

Reclamati on program AC AP.

Average annual and total sediment deposits divided by 142,864 acre-feet, original capaci ty at elevation 1354.8,

and 291,4 12 acre-feet, original capacity at elevation 1374.4.

End-of-month elevatio ns from USGS publications, by water year.

12 For wate r year 1993 from October 1992 through March 1993.

13 Original area and capacity recalculated for the 1993 sedimentation study using ACAP.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation DATE May 1994

Table 1. - Reservoir sediment data summary (page 2 of 2).
(1)

Elevation

(feet)

(2)

Original

Area

(acres)

(3)

Original

Capacity

(acre-feet)

)4)

1993

Area

(acres)

(5)

1993

Capacity

(acre-feet)

(6)

Measured

Sediment

Volume

(acre-feet)

(7)

Percent

Measured

Sediment

(8)

Percent

Reservoir

Depth

1374.4 9,422 291,432 9,421 284,079 7,353 100.0 100.0

1370 8,516 251,968 8,501.3 244,650 7,318 99.5 95.4

1365 7,623 211,620 7,602.3 204,391 7,229 98.3 90.1

1360 6,728 175,743 6,704.0 168,625 7,118 96.8 84.9

1355 5,949 144,050 5,915.0 137,078 6,972 94.8 79.7

1354.8 5,915 142,864 5,882 135,898 6,966 94.7 79.4

1350 5,111 116,400 5,087.6 109,571 6,829 92.9 74.4

1345 4,506 92,358 4,327.5 86,034 6,324 86.0 69.2

1342 4,109 79,436 3,806 73,833 5,603 76.2 66.0

1340 3,844 71,483 3,459.0 66,567 4,916 66.8 63.9

1335 3,175 53,935 2,926.5 50,604 3,331 45.3 58.7

1330 2,516 39,708 2,334.5 37,451 2,257 30.7 53.4

1325 2,013 28,385 1,890.8 26,888 1,497 20.4 48.2

1320 1,548 19,483 1,513.9 18,376 1,107 15.0 43.0

1315 1,169 12,690 1,132.1 11,761 929 12.6 37.7

1310 872 7,588 848.3 6,810 778 10.6 32.5

1305 557 4,015 524.4 3,378 637 8.7 27.2

1300 350 1,748 323.1 1,260 488 6.6 22.0

1295 133 540 90.4 226 314 4.3 16.8

1290 30 133 0 0 133 1.8 11.5

1285 11 30 0 0 30 0.4 6.3

1280 1 0 0 0 0 0.0 1.0

1279 0 0 0 0 0 0.0 0.0

(1) Elevation of reservoir water surface.

(2) Original reservoir surface area.

(3) Original calculated reservoir capacity computed using ACAP from original measured surface areas.

(4) Reservoir surface area from 1993 survey.

(5) 1993 calculated reservoir capacity computed using ACAP from 1993 surface areas.

(6) Measured sediment volume = column (3) - column (5).

(7) Measured sediment expressed in percentage of total sediment (7,353).

(8) Depth of reservoir expressed in percentage of total depth (95.4 feet).

Table 2. - Summary of 1993 survey results.
ELEVATION

0

SE3MENT 1375.0 1370,0

501.9 4549

2 1383.1 1244,1

3 128L2 ¶1936

4 12131 11092

5 973.9 882,1

O ¶048 I 927.9

7 988.8 917.8

• 547,1 484.0

9 435,8 351 7

¶0 87.5 188

II 247 10,7

20 2192 191.1

21 1730 1600

22 185.8 ¶434

23 23.5 10.1

30 248.8 2238

31 ¶88.8 151.5

32 42.8 ¶05

40 41.1 22.2

41 2.6 1.0

TOTAL 95480 9519.0

¶365.0 13800 1355,0 1350.0 1345.0 1340.0 1335.0 1330.0 1325.0

413.1 3582 320.2 282.4 280.2 235.4 205.4 181.8 183,4

1148,3 10681 988.3 864.2 788.0 695.4 8288 543.1 492.0

1124,1 ¶042,2 9682 891.9 809.6 718.7 828.9 528.2 465.3

10028 9181 9324 781.1 718.0 8379 578,4 500.5 438.3

819,9 733,0 075.7 031.0 587.7 532.3 4870 4309 381.5

841.5 7881 883,1 593.4 542.4 491.3 425.9 253.2 55,9

844.8 777,8 701.5 844.2 570.0 381.7 112.0 8.5 0.0

439.8 398 0 312.5 ¶00.8 ¶5.7 8.0 0.5 0 0 0,0

227.1 885 17,5 5.1 0.0 0.0 0,0 00 0.0

11,0 50 0,0 00 0.0 00 00 00 0,0

33 00 0.0 0.0 0.0 0,0 0,0 00 0.0

109.0 ¶552 ¶383 121,9 107.8 92.4 90.4 805 188

¶40.2 ¶28.7 113.2 99.8 780 52.4 29.7 3.4 0.0

112.8 762 39.0 18.0 0.8 ' 0.0 0.0 00 0.0

1.7 00 . , 0.0 0.0 0.0 0.0 0.0 0.0 0.0

190.9 175.2 148.9 788 29.3 08 0.0 00 0.0

117.3 60,4 8.9 2.7 0.0 0.0 0.0 0,0 0.0

1.0 00 0.0 0.0 00 0.0 0.0 00 00

¶0.8 35 1.2 0.0 0.0 0.0 0.0 0.0 0.0

0.0 00 0.0 0.0 0.0 0.0 0.0 0.0 0.0

7823.0 07280 5948.0 5111.0 4508.0 3644,0 3175.0 2518.0 2013.0

OIgIttx.d irea. In acres for segments of Fort Cobb Re,srvolr.

¶320.0 1315.0 1310.0 1305.0 13000 12850 ¶290.0 ¶2850 ¶2900

¶41.1 ¶234 ¶108 987 918 87.3 ¶60 24 ¶0

431.7 385.3 347.0 288 2 207 7 53.0 9,8 5 7 00

395.4 , 3460 291.8 ¶588 433 ¶0.1 42 29 00

377.0 295.3 ¶12.8 ¶3,1 72 21 00 0.0 00

¶909 10.1 10,1 0,4 00 00 0.0' 00 00

5,9 30 00 00 00 00 0.0 00 00

0.0 0,0 00 00 0,0 00 00 00 00

0.0 0.0 0.0 0.0 00 0.0 00 00 00

0.0 0,0 00 00 00 0.0 0.0 00 00

00 0.0 00 00 00 0.0 00 00 00

0.0 0.0 00 0 0 0.0 0.0 0.0 0.0 0 0

0.1 0.0 0.0 00 0.0 0.0 00 00 00

0.0 0.0 00 00 00 00 0.0 00 00

0.0 0.0 00 00 00 0.0 00 00 0.0

0.0 0.0 00 0.0 0.0 00 0.0 00 0,0

0.0 0.0 0.0 00 00 0.0 0.0 00 00

0.0 0.0 00 00 0.0 0,0 0.0 0.0 00

0.0 00 00 0.0 00 00 0.0 00 00

0.0 0.0 0.0 0.0 0,0 0.0 0.0 00 00

0.0 0.0 0.0 00 00 00 0.0 00 00

¶546.0 ¶189,0 872.0 557.0 350,0 ¶33.0 30.0 11.0 1.0

Table 3. - Segmented reservoir areas.
I.

N

•1

6 0 6 12

21' III I

SCALE or MILES

Figure 1. - Fort Cobb Reservoir location map.
Space intentionally left blank due to security concerns 
// N

NNNNNN

000

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33 L

N //

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---------

______________________

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R-(L G-

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-N

R-24L

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R-5L--,

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SCALS OF 57161

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I ron Cobb

94'JGE M(JP4WJ71741 - -- __________ flCtLHLl4',,

21135

- 7,00 3,54755 SCEVATION ORAoi,liO

7.164868 NORTH 1 (570 2.1 508211 { 547,6

(415 ) NU4.4BE

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83 [84 (770' _l6l 84928 (39081 672440 8547337 (39606 [ 85

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687 43 2o 45 820 4 6 85 681 -46 I _) 8 3 I

1412 34 e5i"22

692,03156 _I,5-16,I85 26 4383 31 586,107, 7'S 1,842,286 2 L1409 81 853-522-

-7 1696,40027 0539,4577, 143613 699,645 65 1,839,01302 j 1418.01 853-322-IC

3 -8_,L.697,03,!J-._ 1.634,49956 1402,16 592.0'S 3 ,83 .c-4073_4 415 9 853-522-17:

- 9 I 702259 2 - I930,279 82 I 4 05. 77,0. 75 54 I, 828, 290 89 4 4 3 853 - 522-

-io'l 706, 3-0 .526.138 52 433 49 706,283 ?

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3,1 I 2 3 1,8 I 9,445 53 (45 98 95 3 - 522- C

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2-201 604,74670 l,5.7,CI2 86 399 32 £65454 IS 1,854,47960 140504 653-522-:

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- 13,969 81 - 2 44,I5 03 1478 50 2. I 20 9 .840 . e 9 eo 450 I 2 j 653- 522-1

7 I 5,889 25 I

I 544,905 'e 492 I 7 - 3 9 - I i, 42, 7' I £ 457 58,.! 653 522 - I -

1431 dl 7 "07,2-6 3 1.631.54073 L/-.J853-522-''---40j 591,45669 1,530,72237

O'.4j E_92.00626 .576.3048, 2:111628.057401

35 9

/

IfNN !iJ) ' LrN,

!

.4 LNJ \

/)' N .R- ,RN -<N

/17

N

/

(['N',-.,N,)

'/3

,,,rfO 5,4115

U (PA*1'(A' OP $t INTO 505

4V45N1714 045,0 P5O.ICGT.00L4I0'.

FORT COBS DIVISION

FORT COBB RCSERVOIR

SEDIMENT RANGE L(WES

--_________

LOCATION MAP ______

I..I,G - P,.S O41NU(D

IICW I B.J..IPAOV(O

•'IQ AS'O, 0.LAI' 0*A, IS.

Figure 3. - Fort Cobb Reservoir range location map.

/

/

/

13

1 8 NJ \/'

C-3 J-N
WiDTH ADJUSTMENT METHOO FOR REVISING

CONTOUR AREAS IN COMPUTATION OF

RESERVOIR SEDIMENTATION

$ediirient

'I

Sediment

Schematic Segment

of Reservoir

Initial Survey New Survey

x Contour Area 4, Contour Area (Computed)

Downstream Width W,' Downstream Width

Upstream Width W," Upstream Width

1 II It I

Figure 4. - Width adjustment method for revising contour areas.

15
AREA (100 ACRES)

Li

Li

z

D

>

Li

Li

1380

1375

1370

1365

1360

1355

1350

1345

1340

1335

1330

1325

1320

1315

1310

130

1300

1295

1290

1285

1201

127

12711

100 9(1) 80 7 0 60 5(1) 40 30 20 11] U

-

-

__

7/CAPACITY AREA \

__

/

__

____

LEGEND _____ _____

_____ _________

1993 SURVEY

____ _____

1959 SURVEY

0 300 600 900 1UU. I5UU tUUU IUU

CAPACITY (100 ACRE-rLLT)

Figure 5. - Area and capacity curves - Fort Cobb Reservoir.

'tuu 3000
'•1

FORT COBB RESERVOIR SEDIMENT SURVEY

1360

1350

1340

1330

IL

. 1320

C

0

>

w

1300

1290

1280

I 'Y7A

Pond Creek

RL8.

1993 Thalweg

RL6 -

Original ThalwN.

I I _7

12 10 8 6 4

Miles Above Axis of Dam

Figure 6. - Longitudinal profile - Pond (Cobb) Creek.

RL2 RL1I

I I I

2 0
FORT COBB RESERVOIR SEDIMENT SURVEY

1370

1360

1350

4-a

(I)

1340

>a) 1330

w

1320

1310

1300 -

4

I j I I I I

I

I J I I

I

I

WUlow Creek

RL23

1993 Thalweg

Original Thaiweg

RL21

3.5 3 2.5 2 1.5

Miles Above Axis of Dam

Figure 7. - Longitudinal profile - Willow Creek.

RL2O

1 .5 0
10-21-1993 02: 18: 03 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: fpbora PLOT 1

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 1

________ ORIGINAL SURVEY ------- 1993 SURVEY

1420

1400

1360

FLU 360

LU

U-.

1

Z 340

0

H-

>

LU

1

1320

-J

LU

1300

1280

1260

00

DISTANCE - FEET

Figure 8. - Sediment Range 1 - Pond Creek.

Sj

D 10 00 20 00 30 00 40 00 50 00 60 00 70 00 8000 90 00 100 00 11000 12000 13000 140
10-21-1993 02: IB: 24 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a; fobpra PLOT 2

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 2

_______ ORIGINAL SURVEY j93 SURVEY

1420

1400

1380

ILU

LU

Li. 1360

2:

0

1340

1320

1300

1280

- '00

DISTANCE - FEET

Figure 9. - Sediment Range 2 - Pond Creek.

__________ f

/ (

________/ ____

0 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 o oo 10 000 110 00 12000 130
I •

-------

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 3

_______ ORIGINAL SURVEY j93 SURVEY

1400

1380

1360

w

w

LL

1340

W 1320

1300

1280

_____

I

4

_

/

I

________

___________

__

) 10 00 20 00 30 00 40 00 5000 60 00 70 00 80 00 o oo 100 00 110 00 120

DISTANCE - FEET

00

Figure 10. - Sediment Range 3 - Pond Creek.
jo-21-jgg3 02: 25: 07 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: toborb PLOT I

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 4

_______ ORIGINAL SURVEY 1993 SURVEY

1400

1390

1380

1370

w

1360

:z: 1350

D

II

1340

w

-J

w

1330

1320

1310

1300(

00

DISTANCE - FEET

Figure 11. - Sediment Range 4- Pond Creek.

D 1000 20 00 30 00 40 00 5000 60 00 70 00 8000 90 00 100
., . I)

O-21--993 02: 25: 25 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: fcobprb PLOT

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 5

_______ ORIGINAL SURVEY 1993 SURVEY

1460

1440

1420

LU 4 0

Lii

1 0

LL

Z 1380

0

F-

>

LU 1360

-J

LU

1340

1320

1300(

DISTANCE - FEET

Figure 12. - Sediment Range 5 - Pond Creek.

_ _

; _ _ _ _

D 1000 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90(
1410

1400

1390

1380

HLU

LU

U1370

z

D

1360

>

LU

-J

LU 1350

1340

133C

1 32C

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 6

ORIGINAL SURVEY 1993 SURVEY

-' - -

-

0 10 00 2000 30 00 40 00 50 00 6000 70 00 80

DISTANCE - FEET

Figure 13. - Sediment Range 6 - Pond Creek.
10-21-1993 02: 25: 55 BUREAU OF RECLAMATION PLTSYS VEP I PSPLT a: fcoborb PLOT 4

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 7

_______ ORIGINAL SURVEY 1993 SURVEY

1440

1420

1400

ILU

LU

1i

Z 1380 11

'-1

I-

>

LU-J ________ LU 1360

1340

1320 DO

DISTANCE - FEET

Figure 14. - Sediment Range 7 - Pond Creek.

I

_ _ _ _ _

\

_

'II

___//

__

Li 10 00 20 00 30 00 40 00 50 00 60 00 70 00 6O
01-17-1994 04: 45: 17 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: fcoborb PLOT 5

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 8

_______ ORIGINAL SURVEY ------- 1993 SURVEY

1420

1410

1400

ft 1390

Li

1380

Li-i 1370

-J

w

1360

1350

1340

DISTANCE - FEET

Figure 15. - Sediment Range 8 - Pond Creek.

) 500 10 00 1500 20 00 2500 30 00 3500 40 00 4500 5000 5500 60(
-------

10-21-1993 02: 26: 22 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: foborb PLOT 7

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 20

_______ ORIGINAL SURVEY 1993 SURVEY

1410

1400

1390

1380

FLU

1370

1360

1350

LU

-J

LU

1340

1330

1 320

1310

DISTANCE - FEET

Figure 16. - Sediment Range 20 - Willow Creek.

/

J 20 0 40 0 60 0 8 00 10 00 1200 14 00 1600 1800 20 00 2200 2400 2600 2800 3000 32(
10-21-1993 02: 26: 34 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: fcoborb PLOT

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 21

_______ ORIGINAL SURVEY 1993 SURVEY

1420

1410

1400

1390

Fw

1380

1370

1360

w

-J

w

1350

1340

1330

1320

- - DO

DISTANCE - FEET

Figure 17. - Sediment Range 21 - Willow Creek.

/

/

- - / . - - -

0 500 10 00 1500 20 00 25 00 30 00 35 00 4000 45 00 501
_

1o-2-1gg3 02: 26: 47 BUREAU OF RECLAMATION PLTSYS VER I PSPLT a: fcoborb PLOT 9

FORT COB RESERVOIR

GROUND PROFILE FOR SECTION 22

_______ ORIGINAL SURVEY 1993 SURVEY

1430

1420

1410

1400

ILU

1390

Z 1380

0

I1370

LU

-J

LU

1360

1350

1340

1330

-

DISTANCE - FEET

Figure 18. - Sediment Range 22 - Willow Creek.

-

*1 - ______________ ______________ ______________

______________ ______________

1 ______________ ______________

D 50 0 10 00 1500 20 00 25 00 30 00 3500 40(
01-17-1994 04: 46: 07 BUREAU OF RECLAMATION PLTSYS VER I PSPLT : fcoborb PLOT iO

FORT COBB RESERVOIR

GROUND PROFILE FOR SECT]ON 23

_______ ORIGINAL SURVEY 1993 SURVEY

1460

1450

1440

1430

j3 1420

LiJ

L

1410

0 D

1400

>

1390

uJ

1380

1370

1360

1350

DISTANCE - FEET

Figure 19. - Sediment Range 23 - Willow Creek.

/

_ _ _ __ __ _ __ _ A __ _ _

ii!

_ _ _ _ _ ___

0 2 00 400 60 0 80 0 10 00 1200 14 00 1600 1800 20 00 2200 2400 26 00 2800 3000 32
o-21-igg3 02: 27: 04 BUREAU OF RECLAMATION PLTSYS VER 1 PSPLT a: fcoborb PLOT 11

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 30

_______ ORIGINAL SURVEY 1993 SURVEY

1440

1430

1420

1410

LU

U1400

I 1390

z

D

>

1380

70

LU

13

1360

1350

1340

1330

- - -- - )0

DISTANCE - FEET

Figure 20. - Sediment Range 30 - Lake Creek.

N

__ _ _ _ _ _

D 50 0 10 00 15 00 20 00 2500 30 00 35 00 40 00 45(
4

1480

1460

1440

ILU

LU

Uz

0

I-1

F-

>

LU

-J

LU

1420

1400

1380

1360

1340

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 31.

ORIGINAL SURVEY 1993 SURVEY

/

/

0 2 00 4 00 6 00 8 00 1000 12 00 14 00 16 00 1800 2000 2200 24 00 26 00 28 00 30 00 3200 34 00 36(

DISTANCE - FEET

Figure 21. - Sediment Range 31 - Lake Creek.
S -,

-------

_

01-17-1994 04: 45: 35 BUREAU OF RECLAMATION PLTBYS VER I PSPLT a: tcoborb PLOT 14

FORT COBB RESERVOIR

GROUND PROFILE FOR SECTION 40

_______ ORIGINAL SURVEY 1993 SURVEY

1440

1430

1420

1410 N ________ ________ ________ ________ ________ ________ ________ ________

FuJ N

U1400 __ __ __ __ __ __ __ __ __

z

D

II I' 1390 _________ _________ ________ _________ ________ ________ ________

_________

>

I

w

-J /

w 1380 ___ ___ _ ___ _ _ ___ _ ___ _ ___ ___

1370 ____________ 1 __

i

1360

1350o 200 400 600 800 1000 1200 1400 1600 1800

DISTANCE - FEET

Figure 22. - Sediment Range 40 - Camp Creek.

Mission

The mission of the Bureau of Reclamation is to manage, develop, and

protect water arid related resources in an environmentally and

economically sound manner in the interest of the American Public.