CLARK CANYON RESERVOIR

2000 RESERVOIR SURVEY

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U.S. Department of the Interior

Bureau of Reclamation
REPORT DOCUMENTATION PAGE Form Approved

0MB No. 0704-0188

1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

August 2001 Final

_______________________________

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Clark Canyon Reservoir PR

2000 Reservoir Survey

6. AUTHOR(S)

Ronald L. Ferrari

______________________

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

REPORT NUMBER

Bureau of Reclamation, Technical Service Center, Denver CO 80225-0007 ___________________________

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

Bureau of Reclamation, Denver Federal Center, P0 Box 25007,

Denver CO 80225-0007 DIBR

____________________________

11. SUPPLEMENTARY NOTES

Hard copy available at Bureau of Reclamation Technical Service Center, Denver, Colorado

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

13. ABSTRACT (/vkLrimum 200 words)

The Bureau of Reclamation (Reclamation) surveyed Clark Canyon Reservoir in June of 2000 to develop a topographic map and

compute a present storage-elevation relationship (area-capacity tables). The data were used to calculate reservoir capacity lost due

to sediment accumulation since dam closure in August of 1964. The underwater survey was conducted in June of 2000 near

reservoir elevation 5538 feet (project datum). The underwater survey used sonic depth recording equipment interfaced with a

global positioning system (GPS) that gave continuous sounding positions throughout the underwater portions of the reservoir

covered by the survey vessel. The above-water topography was detennined by digitizing the developed contour lines from the

U.S. Geological Survey quadrangle (USGS quad) maps of the reservoir area. The new topographic map of Clark Canyon

Reservoir was developed from the combined digitized USGS quad contours and June 2000 underwater measured topography.

This study assumed no change from elevation 5540 and above.

As of June 2000, at top ofjoint use water surface elevation (feet) 5,546.1, the surface area was 5,151 acres with a total capacity of

174,367 acre-feet Since initial filling in August of 1964, about 4,106 acre-feet of sediment have accumulated in Clark Canyon

Reservoir below elevation 5,546.1, resulting in a 2.3 percent loss in reservoir volume. Since 1964, the estimated average annual

rate of reservoir capacity lost to sediment accumulation is 114.7 acre-feet

14. SIJBJECTTERMS 15. NUMBER OF PAGES

reservoir area and capacity! sedimentation! reservoir surveys! sonar! sediment distribution! ____________________

contour area! reservoir area! sedimentation survey! global positioning system 16. PRICE CODE

17. SECURITY 18. SECURITY 19. SECURiTY CLASSIFICATION 20. LIMITATION OF

CLASSIFICATION CLASSiFICATION OF ABSTRACT ABSTRACT

OF REPORT OF THIS PAGE

UL

UL UL IlL

NSN 7540-01-280-5500 Standard Foim 298 (Rev. 2-89)

Prescribed by ANSI Std. 239-18

298-102
CLARK CANYON RESERVOIR

2000 RESERVOIR SURVEY

by

Ronald L. Ferrari

Sedimentation and River Hydraulics Group

Water Resources Services

Technical Service Center

Denver, Colorado

August 2001
ACKNOWLEDGMENTS

The Bureau of Reclamation's (Reclamation) Sedimentation and River

Hydraulics Group of the Technical Service Center (TSC) prepared and

published this report. Stephanie Schwinghammer and Ronald Ferrari of the

TSC conducted the hydrographic survey. Ronald Ferrari completed the

data processing needed to generate the new topographic map and areacapacity tables. Sharon Nuanes of the TSC completed the final map

development. Kent Collins of TSC performed the technical peer review of

this documentation.

Mission Statements

The mission of the Department of the Interior is to protect and provide

access to our Nation's natural and cultural heritage and honor our trust

responsibilities to tribes.

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

protect water and related resources in an environmentally and economically

sound manner in the interest of the American public.

The infonnation 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 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 I

Reservoir Operations 2

Hydrographic Survey Equipment and Method 3

GPS Technology and Equipment 3

Survey Method and Equipment 5

Clark Canyon Reservoir Datums 6

Reservoir Area and Capacity 6

Topography Development 6

Development of 2000 Contour Areas 7

2000 Storage Capacity 7

Reservoir Sediment Analyses 8

References 9

TABLES

Table

1 Reservoir sediment data summary (page 1 of 2) 10

1 Reservoir sediment data summary (page 2 of 2) 11

2 Summary of 1999 survey results 12

FIGURES

Figure

1 Clark Canyon Reservoir location map 13

2 Clark Canyon Dam, plan and sections 14

3 Clark Canyon Reservoir topographic map, No. 699-D-569 15

4 Clark Canyon Reservoir topographic map, No. 699-D-570 17

5 2000 area and capacity curves 19

'II

INTRODUCTION

Clark Canyon Reservoir and dam are located in Beaverhead County at the head of the Beaverhead

River about 20 miles southwest of Dillon, Montana (fig. 1). Clark Canyon Reservoir as part of the

East Beach Unit provides irrigation, flood control, and recreation benefits. The dam and reservoir

are operated and maintained by the East Bench Irrigation District.

Clark Canyon Dam was completed in 1964 and is a zoned earthflll structure whose dimensions are

(fig. 2):

Hydraulic height1 113.9 feet2

Top width 36 feet

Crest elevation 5,578.0 feet

Structural height 147.5 feet

Crest length 2,950 feet

The spiliway is located in the left abutment of the dam and consists of an inlet channel, a free

overflow crest at elevation 5560.4, a chute with underlying drainage gallery, and a stilling basin.

The spillway provides a discharge of 9,530 cubic feet per second (cfs) at reservoir elevation 5571.9

The outlet works, through the left abutment, consists of an approach channel, concrete intake

structure, concrete conduit, a gate chamberwith fourhigh-pressure gates, an access shaft, shaft house

and stilling basin. The discharge capacity of the outlet works is 2,325 cfs at reservoir elevation

5,547.

The total drainage area above Clark Canyon Dam is 2,321 square miles of which 1,751 square miles

are considered sediment contributing. Sediments from the remaining drainage area are trapped by

Lima Reservoir that has a drainage area of 570 square miles. Clark Canyon Reservoir has an average

width of 2.0 miles with a length of around 4.5 miles.

SUMMARY AND CONCLUSIONS

This Reclamation report presents the 2000 results of the survey of Clark Canyon Reservoir. The

primary objectives of the survey were to gather data needed to:

• develop reservoir topography

• compute area-capacity relationships

• estimate storage depletion caused by sediment deposition since dam closure

1The definition of such terms as "hydraulic height," "structural 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.

2Elevation levels are shown in feet. All elevations shown in this report are based on the original project

datum established by U.S. Bureau of Reclamation which is tied to the National Geodetic Vertical Datum of 1929.

:1-
A Real-time Kinematic (RTK) GPS control survey was conducted to establish a temporary

horizontal and vertical control point for the reservoir survey. The horizontal control was established

in Montana state plane coordinates in the North American Datum of 1983 (NAD83). The RTK GPS

control was conducted with the base set on the NGS datum point "Dillon" located in the town of

Dillon, Montana. All elevations in this report are reference to the Reclamation project datum that

is tied to the NGVD29

The underwater survey was conducted in June of 2000 near reservoir water surface elevation 5,538.

The bathymetric survey was run using sonic depth recording equipment interfaced with a differential

global positioning system (DGPS) capable of determining sounding locations within the reservoir.

The system continuously recorded depth and horizontal coordinates of the survey boat as it was

navigated along grid lines covering Clark Canyon Reservoir. The positioning system provided

information to allow the boat operator to maintain a course along these grid lines. Water surface

elevations recorded by the reservoir gauge (tied to the Reclamation vertical datum) during the time

of collection were used to convert the sonic depth measurements to true reservoir bottom elevations.

The above-water topography was determined by digitizing the developed contour lines from the U.S.

Geological Survey quadrangle (USGS quad) maps of the reservoir area.

The new Clark Canyon Reservoir topographic maps are a combination of the USGS quad contours

and underwater survey data. The 2000 reservoir surface areas at predetermined contour intervals

were generated by a computer graphics program using the collected reservoir data. The 2000 area

and capacity tables were produced by a computer program that uses measured contour surface areas

and a curve-fitting technique to compute area and capacity at prescribed elevation increments

(Bureau of Reclamation, 1985).

Tables 1 and 2 contain a summary of the Clark Canyon Reservoir sedimentation and watershed

characteristics for the 2000 survey. The 2000 survey determined that the reservoir has a total storage

capacity of 174,367 acre-feet and a surface area of 5,151 acres at reservoir elevation 5,546.1. Since

closure in August of 1964, the reservoir had an estimated volume change of 4,106 acre-feet below

reservoir elevation 5,546.1. This volume represents a 2.3 percent loss in total capacity and an

average annual loss of 114.7 acre-feet per year.

RESERVOIR OPERATIONS

Clark Canyon Dam operates as part of the East Bench Unit to provide flood control, irrigation water,

and recreational use. The June 2000 area-capacity tables show 325,324 acre-feet of total storage

below the maximum water surface elevation 5,571.9. The 2000 survey measured a minimum

elevation of 5,449.0. The following values are from the June 2000 area-capacity tables:

• 71,882 acre-feet of surcharge between elevation 5,560.4 and 5,571.9.

• 79,075 acre-feet of flood control storage between elevation 5,546.1 and 5,560.4.

• 50,207 acre-feet ofjoint use storage below elevation 5,535.7 and 5,546.1.

• 123,099 acre-feet of conservation use between elevation 5,470.6 and 5,535.7.

• 1,057 acre-feet of inactive storage between elevation 5,455.0 and 5,470.6.

• 4 acre-feet of dead storage below elevation 5,455.0.

2
The Clark Canyon Reservoir inflow and end-of-month stage records in table 1, operation period

August 1964 through June 2000, show the inflow and annual fluctuation since dam closure. The

estimated average inflow into the reservoir for this operation period was 288,963 acre-feet per year.

Since 1966, the extreme storage fluctuations of Clark Canyon Reservoir ranged from an elevation

of 5,508.7 in 1989 to the maximum recorded elevation of 5,564.7 in 1984.

HYDROGRAPHIC SURVEY EQUIPMENT AND METHOD

The hydrographic survey equipment was mounted in the cabin of a 24-foot trihull aluminum vessel

equipped with twin in-board motors. The hydrographic system contained on the survey vessel

consisted of a GPS receiver with a built-in radio and an omnidirectional antenna, a depth sounder,

a helmsman display for navigation, a computer, and hydrographic system software for collecting

underwater data. Power to the equipment was supplied by an on-board generator.

The shore equipment included a second GPS receiver with an external radio and an omnidirectional

antenna. The GPS receiver and antenna were mounted on a survey tripod over a known datum point.

To obtain the maximum radio transmission range, known datum points with clear line-of-sight to

the survey boat were selected. The power for the shore unit was provided by a 12-volt battery.

GPS Technology and Equipment

The hydrographic positioning system used at Clark Canyon Reservoir was Navigation Satellite

Timing and Ranging (NAVSTAR) GPS, an all-weather, radio-based, satellite navigation system that

enables users to accurately determine three-dimensional position. The NAVSTAR system's primary

mission is to provide passive global positioning and navigation for land-, air-, and sea-based strategic

and tactical forces and is operated and maintained by the Department of Defense (DOD). The GPS

receiver measures the distances between the satellites and itself and determines the receiver's

position from intersections of the multiple-range vectors. Distances are determined by accurately

measuring the time a signal pulse takes to travel from the satellite to the receiver.

The NAVSTAR system consists of three segments:

The space segment is a network of 24 satellites maintained in a precise orbit about 10,900

nautical miles above the earth, each completing an orbit every 12 hours.

The ground control segment tracks the satellites, determining their precise orbits. Periodically,

the ground control segment transmits correction and other system data to all the satellites, and

the data are then retransmitted to the user segment.

• The user segment includes the GPS receivers which measure the broadcasts from the satellites

and calculate the position of the receivers.

3
The GPS receivers use the satellites as reference points for triangulating their position on earth. The

position is calculated from distance measurements to the satellites that are determined by how long

a radio signal takes to reach the receiver from the satellite. To calculate the receiver's position on

earth, the satellite distance and the satellite's position in space are needed. The satellites transmit

signals to the GPS receivers for distance measurements along with the data messages about their

exact orbital location and operational status. The satellites transmit two "L" band frequencies (called

Li and L2) for the distance measurement signal. At least four satellite observations are required to

mathematically solve for the four unknown receiver parameters (latitude, longitude, altitude, and

time); the time unknown is caused by the clock error between the expensive satellite atomic clocks

and the imperfect clocks in the GPS receivers.

The GPS receiver's absolute position is not as accurate as it appears in theory because of the function

of range measurement precision and the geometric position of the satellites. Precision is affected

by several factors-time, because of the clock differences, and atmospheric delays caused by the

effect of the ionosphere on the radio signal. Geometric dilution of precision (GDOP) describes the

geometrical uncertainty and is a function of the relative geometry of the satellites and the user.

Generally, the closer together in angle two satellites are from the receiver, the greater the GDOP.

GDOP is broken into components: position dilution of precision (x,y,z) (PDOP), and horizontal

dilution of precision (x,y) (HDOP). The components are based only on the geometry of the

satellites. The PDOP and HDOP were monitored at the survey vessel's GPS receiver during the

Clark Canyon Reservoir Survey, and for the majority of the time they were less than 3, which is

within the acceptable limits of horizontal accuracy for Class 1 and 2 level surveys (Corps of

Engineers, 1994).

An additional and larger error source in GPS collection is caused by false signal projection, called

selective availability (S/A). The DOD implements S/A to discourage the use of the satellite system

as a guidance tool by hostile forces. Positions determined by a single receiver when S/A is active

can have errors of up to 100 meters. In May of 2000 the use of S/A was discontinued, but the errors

of a single receiver are still around ±10 meters.

A method of collection to resolve or cancel the inherent errors of GPS is called differential GPS

(DGPS). DGPS is used during the reservoir survey to determine positions of the moving survey

vessel in real time. DGPS determines the position of one receiver in reference to another and is a

method of increasing position accuracies by eliminating or minimizing the uncertainties.

Differential positioning is not concerned with the absolute position of each unit but with the relative

difference between the positions of two units, which are simultaneously observing the same

satellites. The inherent errors are mostly canceled because the satellite transmission is essentially

the same at both receivers.

4

At a known geographical benchmark, one GPS receiver is programmed with the known coordinates

and stationed over the geographical benchmark. This receiver, known as the master or reference

unit, remains over the known benchmark, monitors the movement of the satellites, and calculates

its apparent geographical position by direct reception from the satellites. The inherent errors in the

satellite position are determined relative to the master receiver's programmed position, and the

necessary corrections or differences are transmitted to the mobile GPS receiver on the survey vessel.

4
For the Clark Canyon Reservoir survey, position corrections were determined by the master receiver

and transmitted via an ultra-high frequency (UHF) radio link every second to the survey vessel

mobile receiver. The survey vessel's GPS receiver used the corrections along with the satellite

information it received to determine the vessel's differential location. Using DGPS can result in submeter positional accuracies for the survey vessel.

The Sedimentation and River Hydraulics Group conducts their bathymetric surveys using Real-time

Kinematic (RTK) GPS. The major benefit of RTK versus DGPS is precise heights can be measured

in real time for monitoring water surface elevation changes. The basic outputs from an RTK receiver

are precise 3D coordinates in latitude, longitude, and height with accuracies on the order of 2

centimeters horizontally and 3 centimeters vertically. The output is on the GPS datum of WGS-84

which the hydrographic collection software converted into Montana's NAD83 state plane coordinate

system. The system employs two receivers, like with DGPS, that collect additional satellite data that

allows on-the-fly centimeter accuracy measurements.

Survey Method and Equipment

The Clark Canyon Reservoir hydrographic survey collection was conducted June 7 through June 10

of 2000 between water surface elevations 5,537.0 and 5537.9 (Reclamation project datum). The

bathymetric survey was run using sonic depth recording equipment, interfaced with an RTK GPS,

capable of determining sounding locations within the reservoir. The survey system software

continuously recorded reservoir depths and horizontal coordinates as the survey boat moved across

closely-spaced grid lines covering the reservoir area. Most of the transects (grid lines) were run

somewhat in a north or south direction of the reservoir at a 400-foot spacing. Data was also

collected along the shore as the boat traversed between transects. The survey vessel's guidance

system gave directions to the boat operator to assist in maintaining the course along these

predetermined lines. During each run, the depth and position data were recorded on the notebook

computer hard drive for subsequent processing.

The 2000 underwater data were collected by a depth sounder that was calibrated by lowering a

deflector plate below the boat by cables with known depths marked by beads. The depth sounder

was calibrated by adjusting the speed of sound, which can vary with density, salinity, temperature,

turbidity, and other conditions. The collected data were digitally transmitted to the computer

collection system via a RS-232 port. The depth sounder also produces an analog hard-copy chart

of the measured depths. These graphed analog charts were printed for all survey lines as the data

were collected and recorded by the computer. The charts were analyzed during post-processing, and

when the analog charted depths indicated a difference from the recorded computer bottom depths,

the computer data files were modified. The water surface elevations at the dam, recorded by a

Reclamation gauge, were used to convert the sonic depth measurements to true lake-bottom

elevations.

5
Clark Canyon Reservoir Datums

Prior to the underwater survey in June 2000, a RTK GPS survey was conducted to establish a

horizontal and vertical control point that overlooked Clark Canyon Reservoir. The National

Geodetic Survey control point "Dillon" in the town of Dillon, Montana was used as the base station

for the control survey. The radio link between Dillon and Clark Canyon Reservoir was intermittent,

but control information appeared to be good for the horizontal and close for the vertical

measurements. All vertical information in this report was referenced to the reservoir water surface

gauge measurements during the time of this survey. The gauge is referenced to the Reclamation

project datum that is reported as NGVD29.

RESERVOIR AREA AND CAPACITY

Topography Development

The topography of Clark Canyon Reservoir was developed from the 2000-collected underwater data

and from the USGS quad maps. The upper contours of Clark Canyon Reservoir were developed by

digitizing the contour lines of elevation 5,542 and 5,560 from the USGS quad maps that covered the

reservoir area. The USGS quad maps were developed from aerial photography dated 1964. There

was a small area of the dam and reservoir not covered by the 1964 aerial that did not appear on the

Dalys, Montana quad map. For this study, this area was interpolated using available original

information. ARC/INFO V7.0.2 geographic information system software was used to digitize the

USGS quad contours. The digitized contours were transformed to Montana's NAD 1983 state plane

coordinates using the ARC/INFO PROJECT command. The resulting digitized areas from the

USGS quad contours compared well with the original contour areas. The original computed surface

area for elevation 5542.0 was 4,929 acres compared to the digitized computed area of 4,930.5 acres.

The original area for elevation 5560.0 was measured as 5,880 acres compared to the digitized

computed area of 5,879 acres.

The elevation 5,542.0 contour that was digitized from USGS quad maps was used to perform a clip

of the Clark Canyon Reservoir triangular irregular network (TiN) such that interpolation was not

allowed to occur outside the 5,542.0 contour. This complete contour was selected since it was the

closest complete elevation to represent the reservoir at the time of the survey which was conducted

near reservoir elevation 5,537. This clip was performed using the hardclip option of the ARC/INFO

CREATET1N command. Using ARCEDIT, the underwater collected data and digitized contours

from the quad maps were plotted. The plot found that the underwater data did not completely lie

within this clip, which would require some modifications to include the entire underwater data set.

These areas included the north and some on the south shores of the reservoir. It is assumed that most

of this occurred due to shoreline erosion caused by the high winds that occur on this reservoir. Using

select and move commands within ARCEDIT, the vertices of the 5,542.0 clip were shifted to fit all

the collected underwater data.

Contours for the reservoir below elevation 5,542.0 were computed from the underwater data set

using the triangular irregular network (TIN) surface modeling package within ARC/INFO. A TIN

6
is a set of adjacent, non-overlapping triangles computed from irregularly spaced points with x,y

coordinates and z values. TIN was designed to deal with continuous data such as elevations. The

TiN software uses a method known as Delaunay's criteria for triangulation where triangles are

formed among all data points within the polygon clip. The method requires that a circle drawn

through the three nodes of a triangle will contain no other point, meaning that sample points are

connected to their nearest neighbors to form triangles using all collected data. This method

preserves all collected survey points. Elevation contours are then interpolated along the triangle

elements. The TIN method is discussed in greater detail in the ARC/INFO V7.O.2 Users

Documentation, (ESRI, 1992).

The linear interpolation option of the ARC/INFO TINCONTOUR command was used to interpolate

contours from the Clark Canyon Reservoir TIN. In addition, the contours were generalized by

filtering out vertices along the contours. This generalization process improved the presentability of

the resulting contours by removing very small variations in the contour lines. This generalization

had no bearing on the computation of surface areas and volumes for Clark Canyon Reservoir since

the areas were calculated from the developed TIN. The areas of the enclosed contour polygons

developed from the survey data were completed for elevations 5,449.0 through elevation 5,542.0.

The contour topography at 5-foot intervals is presented on figures 3 and 4, drawing numbers 699-D569 and 699-D-570.

Development of 2000 Contour Areas

The 2000 contour surface areas for Clark Canyon Reservoir were computed at 1-foot increments

from elevation 5,449.0 to 5,542.0, The 2000 underwater survey measured the minimum reservoir

elevation at 5,449.0. These calculations were performed using the ARC/INFO VOLUIv1iE command.

This command computes areas at user-specified elevations directly from the TIN and takes into

consideration all regions of equal elevation. As indicated above, the underwater data was collected

near reservoir elevation 5,537 and no above water data was collected during the 2000 survey. For

the purpose of this study the measured 2000 survey areas at 5-foot increments from elevation 5,450

through 5,530 were used to compute the new area and capacity tables. Due to the lack of above

water data this study assumed no area change from elevation 5,540 and above. The areas between

elevation 5,530 and 5,540 were computed by the area and capacity program which assumed a

straight line interpolation.

2000 Storage Capacity

The storage-elevation relationships based on the measured surface areas were developed using the

area-capacity computer program ACAP85 (Bureau of Reclamation, 1985). Surface areas at 5-foot

contour intervals from reservoir elevation 5,450.0 to elevation 5,530.0 were used as the control

parameters for computing the Clark Canyon Reservoir capacity. Since this study did not collect any

above water data, the original areas from elevation 5,540 and above were used to complete the table.

The program can compute an area and capacity at elevation increments 0.01- to 1,0-foot by linear

interpolation between the given contour surface areas. The program begins by testing the initial

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

limit. The error limit was set at 0.00000 1 for Clark Canyon Reservoir. The capacity equation is then

7
used over the full range of mtervals 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 basic

area curve over that interval) is utilized until it exceeds the error limit. Thus, the capacity curve is

defined 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 = a1 + a2x + a3x2

where: y = capacity

x = elevation above a reference base

a1 intercept

a2 and a3 = coefficients

Results of the 2000 Clark Canyon Reservoir area and capacity computations are listed in table 1 and

columns 4 and 5 of table 2. On table 2, columns 2 and 3 list the original surface areas and

recomputed capacities. A separate set of 2000 area and capacity tables has been published for the

0.01, 0.1 and 1-foot elevation increments (Bureau of Reclamation 2000). A description of the

computations and coefficients output from the ACAP85 program is included with these tables. Both

the original and 2000 area-capacity curves are plotted on figure 5. As of June 2000, at elevation

5,571.9, the surface area was 6,606.2 acres with a total capacity of 325,324 acre-feet.

RESERVOIR SEDIMENT ANALYSES

Figure 5 is a plot of Clark Canyon Reservoir's original area data versus the 2000 measured areas.

This illustrates the difference between the original and the 2000 measured surface areas. Since

Clark Canyon Dam closure in August 1964, the measured total volume change at reservoir elevation

5,546.1 was estimated to be 4,106 acre-feet. The estimated average annual rate of capacity lost for

this time period (35.8 years) was 114.7 acre-feet per year. The storage loss in terms of percent of

original storage capacity was 2.3 percent. Tables 1 and 2 contain the Clark Canyon Reservoir

sediment accumulation and water storage data based on the 2000 resurvey.

The original 100 year sediment inflow estimate used during the design of Clark Canyon Reservoir

was 10,000 acre-feet for an average annual rate of capacity loss of 100 acre-feet which is near the

2000 survey computed result of 114.7 acre-feet per year. It must be noted that the 2000 area and

capacity table were generated using measured surface areas from elevation 5,530 and below. The

original surface areas from elevation 5,540 and above were used to complete the new area and

capacity table. This assumed no surface area change from elevation 5,540 and above which in all

probability is not the case. The ACAP program computed a straight line interpolation to compute

the surface areas between elevation 5,530 and 5,540. Overlaying the 2000 collected data with the

digitized USGS quad contours appears to indicate there has been shoreline erosion since the original

survey at elevation 5,542, but the only way to confirm this would be to conduct a shoreline survey.

A resurvey of Clark Canyon Reservoir should be considered in the future if major sediment inflow

events are observed, or if the average annual rate of sediment accumulation requires further

clarification.

8
REFERENCES

American Society of Civil Engineers, 1962. Nomenclaturefor Hydraulics, ASCE Headquarters,

New York.

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

Bureau of Reclamation, 1985. Surface Water Branch, ACAP85 User's Manual, Technical

Service Center, Denver CO.

Bureau of Reclamation, 1987(a). Guide for Preparation of Standing Operating Procedures for

Bureau ofReclamation Dams and Reservoirs, U.S. Government Printing Office,

Denver, CO.

Bureau of Reclamation, 1987(b). Design of Small Dams, U.S. Government Printing Office,

Denver CO.

Bureau of Reclamation, May 2000. Denver Office, Clark Canyon Reservoir Area and Capacity

Tables, East Bench Unit, Great Plains Region, Billings, MT.

Corps of Engineers, October 1994. Engineer and Design - Hydrographic Surveying, EM 1110-2-

1003 (FR), Department of the Army, Washington DC,

(www.usace.army.mil/inetiusace.docs/eng-manuals/em.htm).

Environmental Systems Research Institute, Inc. (ESRI), 1992. ARC Command Reftrences.

9
RESERVOIR SEDIMENT

DATA StARY Clark Canyon Reservoir

OF RESERVOIR

DATA SHEET NO.

D 1. OWNER Bureau of Reclamation 2. STREAM Beaverhead River 3. STATE Montana

A 4. SEC. 32 TWP. 9 S RANGE 10 W 5. NEAREST P.O. Grant 6. COUNTY Beaverhead

H 7. LAT 45 00' 06" LONG 112' 51' 27" 8. TOP OF DAM ELEVATION 5578.0 9. SPILLWAY CREST EL 5560.4'

R 10. STORAGE 11. ELEVATI ON 12. ORIGINAL 13. ORIGINAL 14. GROSS STORAGE 15. DATE

E ALLOCATION TOP OF POOL SURFACE AREA, AC CAPACITY, AF ACRE- FEET STORAGE

S BEGAN

E _______________________ ________________________

R a. SURCHARGE 5571.9 6,600

_______________________

71,827

________________________

328,979

V

0

b. FLOOD CONTROL 5560.4 5,903 79,090 257,152

C. POWER 8/64

R d. JOINT USE 5546.1 5,160 50,436 178,062 16. DATE

e. CONSERVATION 5535.7 4,496 126,117 127,626

f. INACTIVE 5470.6 367 1,448 1,509

IoN

BEGAN

g. DEAD 5455.0 23 61 61 8/64

17. LENGTH OF RESERVOIR 4.5 MILES AVG. WIDTH OF RESERVOIR 2.0 MILES

5 18. TOTAL DRAINAGE AREA 2,321 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 11.52 INCHES

19. NET SEDIMENT CONTRIBUTING AREA 1,751 SQUARE MILES 23. MEAN ANNUAL RUNOFF 2.33 INCHES

20. LENGTH MILES AV. WIDTH MILES 24. MEAN ANNUAL RUNOFF 288,963 ACRE-FEET

N 21. MAX. ELEVATION MIN. ELEVATION 25. ANNUAL TEMP. MEAN 43'F RANGE -40'F to 100'F2

S 26. DATE OF 27. 28. 29. TYPE OF 30. NO. OF 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

8/64 Contour CD) 10-ft 5,151' 178,473' .62

D 6/00 35.8 Contour CD) 5-ft 5,151' 174,367' .60

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

A

SURVEY ANNUAL

,

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

6/00 288, 963 718, 116 10, 344, 871 288, 963 10, 344, 871

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.2-YR.

6/00 4106' 114.7 0.066 4106 114.7 0.066

26. DATE OF 39. AV. DRY 40. SED. DEP. TONS/MI.2-YR. 41. STORAGE LOSS, PCT. 42. SEDIMENT

SURVEY WT. (#/FT')

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

6/00 0.064' 2.3'

26.

DATE

43. DEPTH DESIGNATION RANGE BY RESERVOIR ELEVATION

__________________________________________________________________________________

OF

SURVEY

5460-

5465

5460-

5470.6

5470.6

5480

5480-

5495

5495-

5505

5505-

5515

5515-

5525

5525-

5530

5530-

5535.7

5535.7

5546.1

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

6/00 4.0 9.2 12.9 12.8 7.3 5.4 15.8 15.5 13.9 3.2

26.

DATE

44. REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

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

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

jo
45. RANGE IN RESERVOIR OPERATION7

YEAR MAX. 81EV. MIN. 81EV. INFLOW, AF YEAR MAX. ELEV. MDL ELEV. INFLOW, AF

1964 5,493.3

_____________

19,671 1965 5,547.0 5,493.6 336,701

1966 5,542.4 5,521.2 199,264 1967 5,543.6 5,521.3 194,348

1968 5,543.2 5,536.1 252,984 1969 5,543.7 5,535.7 348,496

1970 5,545.6 5,535.7 314,767 1971 5,547.4 5,537.3 428,853

1972 5,542.8 5,535.7 393,999 1973 5,545.5 5,525.3 277,711

1974 5,543.4 5,517.9 266,131 1975 5,556.9 5,516.8 410,178

1976 5,554.5 5,540.5 408,233 1977 5,546.4 5,531.5 211,457

1978 5,547.5 5,533.1 263,965 1979 5,548.3 5,531.0 237,730

1980 5,548.2 5,532.2 250,648 1981 5,550.8 5,534.6 298,216

1982 5,549.6 5,534.6 333,406 1983 5,547.9 5,541.5 386,884

1984 5,564.7 5,542.2 718,116 1985 5,544.9 5,524.4 317,466

1986 5,545.8 5,536.8 250,958 1987 5,544.6 5,536.5 223,408

1988 5,546.6 5,522.1 140,224 1989 5,534.6 5,508.7 109,182

1990 5,531.9 5,511.0 131,346 1991 5,534.1 5,513.9 153,305

1992 5,537.7 5,509.8 133, 115 1993 5,532.3 5,509.9 185,765

1994 5,546.7 5,523.1 175,003 1995 5,553.7 5,523.2 371,093

1996 5,544.0 5,532.0 346,664 1997 5,545.6 5,532.7 322,898

1998 5,551.1 5,539.7 402,243 1999 5,546.5 5,534.7 367,303

2000 5.532.2 163.150 _____________ ____

46. ELEVATION - AREA - CAPALITY DATA FOR 2000 CAPACIT11

_________ ______________ _____________

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

5449.0 0 0 5455 1.2 4 5460 21.4 60

5465 82.9 321 5470 170.6 955 5470.6 184 1,061

5475 284.8 2,093 5480 454.9 3,942 5485 661.8 6,734

5490 929.2 10,712 5495 1,207.5 16,053 5500 1,503.5 22,831

5505 1,824.4 31,151 5510 2,151.3 41,090 5515 2,508.5 52,739

5520 2,966.4 66,427 5525 3,399.6 82,342 5530 3,880.1 100,541

5535 4,343 121,098 5535.7 4,407 124,160 5540 4,805.3 143,968

5546.1 5,151 174,367 5550.0 5,363.0 194,870 5560 5,880.1 251,086

5560.4 5,904 253,442 5570 6,481.0 312,891 5571.9 6,606.2 325,324

47. REMARKS AND REFERENCES

Top of uncontrolled concrete spiliway crest.

2 Bureau of Reclamation Project Data Book, 1981.

Calculated using mean annual runoff value of 718,116 AF, item 24, 8/64-6/00.

Computed annual inflows from 8/64 through 6/00.

Original recomputed surface area and capacity at el. 5,546.1. For sediment computation purposes the original

area and capacity was recomputed by the Reclamation ACAP program using the original 5-foot increment surface

areas.

6

Surface area & capacity at el. 5,546.1 computed by ACAP program.

Inflow values in acre-feet and maximum and minimum elevations in feet by water year from 8/64 through 6/00.

Computed sediment volume at elevation 5,546.1.

Storage losses at elevation 5,546.1.

Capacities computed by Reclamation's ACAP computer program.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation DATE March 2001

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

11
1 2 3 4 5 6 7 8 - - -

2000 2000 Percent of

Elevations Original original 2000 2000 Sediment Percent of Reservoir

Survey Capacity Survey Survey Volume Sediment Depth

(feet) (acres) (acre-feet) (acres) (acre-feet) (acre-feet)

___________

5,571.9 6606.2 329430 6606.2 325324 _____ -___________

i00.1J

5,570.0 6481.0 316997 6481.0 312891 98.5

5,565.0 6181.0 285343 6181.0 281237 94.5

5,560.4 5904.0 257548 5904.0 253442 90.8

5,560.0 5880.1 255191 5880.1 251086 90.5

5,555.0 5622.0 226437 5622.0 222332 - ______ ____________

86.5

5,550.0 5363.0 198976 5363.0 194870 82.5

5,546.1 5151.0 178473 -

5151.0 174367 4106 100.0 79.4

5,542.0 4929.0 157808 4929.0 153702 4106 100.0 76.2

5,540.0 4805.3 148074 4805.3 143968 4106 100.0 74.6

5,535.7 4468.0 128136 4407.0 124160 3976 96.8 71.1

5,535.0 4413.0 125028 4343.0 121098 3930 95.7 70.6

5,530.0 4020.6 103944 3880.1 100541 3403 82.9 66.6

5,525.0 3513.0 85110 3399.6 82342 2768 67.4 62.6

5,520.0 3005.2 68815 2966.4 66427 2388 58.2 58.6

5,515.0 2578.0 54857 2508.5 52739 2118 51.6 54.6

5,510.0 2150.6 43036 2151.3 41090 1946 47.4 50.6

5,505.0 1845.0 33048 1824.4 31151 1897 46.2 46.7

_____

5,500.0 1538.6 24590 1503.5 22831 1759 42.8 42.7

5,495.0 1238.0 17649 1207.5 16053 1596 38.9 38.7

5,490.0 937.1 12212 929.2 10712 1500 36.5 34.7

5,485.0 720.0 8069 661.8 6734 1335 32.5 30.7

5,480.0 503.0 5013 454.9 3942 1071 26.1 26.7

5,475.0 -354.0 2871 284.8 2093 778 18.9 22.7

5,470.6 223.0 1601 184.0 1061 540 13.2 19.2

5,470.0 205.2 1473 170.6 955 518 12.6 18.7

5,465.0 125.0 648 82.9 321 327 -______

8.0 14.8

5,460.0 _____

44.7 224 21.4 60 164 4.0 10.8

5,455.0 22.0 56 1.2 4 52 1.3 6.8

5,450.0 1.0 1 0.0 0 1 0.0 2.8

5, 449. 0 0.0 0 0.0 0 0 0. 0 2 .0

5,446.5 0.0 0 0.0 0 0 0.0

-

0.0

1 Elevation of reservoir water surface.

2 Original reservoir surface area.

_____________ ______________ ______________ )

3 Original reservoir capacity recomputed using ACAP.

______ _

4 Reservoir surface area from 2000 survey. Assume no change from elevation 5,540.0.

5 Reservoir capacity computed using ACAP using surface areas from column 4.

6 Measured sedimert volume - column (3) - columnsf

____________ __________

7 Measured sediment expressed in percentag. of total sediment 4,106.

8

_____ ____

Depth of reservoir expressed in percentage of total depth of 125.4 feet.

______

Table 2. - Sunimaiy of 2000 survey results

12
71

Ci

Ci 'I -

I0

5

tIGATtD A$A

I•I

ICALI O MILtI
Space intentionally left blank due to security concerns 
Horizontal datum based on North

American Datum of 1983, Montn'S

State Plane Coordinate System.

Vertical datum based on the

Bureau of Reclamation Datum.

North American Vertical Datum

of 1929.

15

Figure 3. - Clark Canyon Reservoir topographic map, No. 699-D-569
Pi0

---

-

_

N

wTE

S

_______________ p

L

02

2r !

0

LaCetOfl

Horizontal datum based on North

American Datum ot 1983, Montana's

State Plane Coordinate System.

T'nx'.y

Vertical datum based on the

8jreau of Reclamation Datum.

North American Vertical Datum a?W8L. llaE'a41 of 1929

______-

Dpef. C'/wcdo Ab 200/ 6.99-0-570

17

Figure 4. - C11 Canyon Reservoir topographic map, No. 699-D-570
Area-Capacity Curves for Clark Canyon Reservoir

Area (acre)

6600.0 5940.0 5280.0 4620.0 3960.0 3300.0 2640.0 1980.0 1320.0 660.0 0.0

5,575.0

5,565.0

5,555.0

5,545.0

5,535.0

5,525.0

5,515.0

- >

2

w

5,505.0

5,495.0

5,485.0

5,475.0

5,465.0

5,455.0

5,445.0

rc

__

-___ __

/ Capacity Area

-

fit,

--

• - __________ __________ 2000 Survey __________ __________ ______ _______

- - -Original Survey

),,J( ).U

5,565.0

5,555.0

5,545.0

5,535.0

5,525.0

5,515.0

5,505.0

5,495.0

5,485.0

5,475.0

5,465.0

5,455.0

5,445.0

0 33000 66000 99000 132000 165000 198000 231000 264000 297000 330000

CapacIty (acre-feet)

Figure 5. - 2000 area and capacity curves