ANDERSON RANCH RESERVOIR

1998 SEDIMENTATION SURVEY

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U.S. Department of the Interior

Bureau of Reclamation
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September1999 Final

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4. TITLE AND SUBTITLE 5. FUNDING NU1'1BERS

Anderson Ranch Reservoir PR

1998 Sedimentation 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. DIST IBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Available from the National Technical Information Service,

Operations Division, 5285 Port Royal Road, Springfield VA 22161 __________________________

13. ABSTRACT (Maximum 200 words)

The Bureau of Reclamation (Reclamation) surveyed Anderson Ranch Reservoir in 1998 to develop a topographic map and comput

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

accumulation since dam closure in 1945. The June 1998 underwater survey was conducted near reservoir elevation 4196 feet. Th

November 1998 aerial data was collected near reservoir elevation 4178 feet. The underwater survey used sonic depth recordin

equipment interfaced with a global positioning system (GPS) that gave continuous sounding positions throughout the underwate

portion of the reservoir. The new topographic map of Anderson Ranch Reservoir was developed from the combined 1998 aerial an

underwater measured topography.

As of June 1998, at top of controllable capacity elevation (feet) 4196.0, the surface area was 4,743 acres with a total capacity o

474,942 acre-feet. Since initial filling in December 1945, about 18,236 acre-feet of sediment have accumulated in Anderson Ranc

Reservoir below elevation 4,196.0, resulting in a 3.70 percent loss in reservoir volume. Since December 1945, the estimated averag

annual rate of reservoir capacity lost to sediment accumulation is 346.7 acre-feet

14. SUBJECTTERMS 15. NUMBER OF PAGES

reservoir area and capacity! sedimentation! reservoir surveys! sonar! sediment distributionl

contour area! reservoir area! sedimentation survey! global positioning system

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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

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

Ptescribed by ANSI Sin. 239-18

298-102
ANDERSON RANCH RESERVOIR

1998 SEDIMENTATION SURVEY

by

Ronald L. Ferrari

Sedimentation and River Hydraulics Group

Water Resources Services

Technical Service Center

Denver, Colorado

April 2000
ACKNOWLEDGMENTS

The Bureau of Reclamationts (Reclamation) Sedimentation and River

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

published this report. Ronald Ferrari of TSC conducted the hydrographic

survey with assistance from Mr. Charlie (Pete) Swan of the Pacific

Northwest Region. The aerial data collection and analysis were conducted

by Horizons, Inc. in Rapid City, South Dakota. 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.

U. S. Department of the Interior

Mission Statement

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 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 Reclamation.

The information contained in this report was developed for the Bureau of

Reclamation; no warranty as to the accuracy, useflulness, or completeness

is expressed or implied.

11
CONTENTS

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Introduction 1

Summary and conclusions 2

Reservoir operations 2

Hydrographic survey equipment and method 3

GPS technology and equipment 3

Survey method and equipment 5

Reservoir area and capacity 6

Topography development 6

Development of 1998 contour areas 7

1998 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 1998 survey results 12

FIGURES

Figure

1 Anderson Ranch Reservoir location map 13

2 Anderson Ranch dam, plan and section 14

3 Anderson Ranch Reservoir topographic map, No. 4-D-2244 15

4 Anderson Ranch Reservoir topographic map, No. 4-D-2245 17

5 Anderson Ranch Reservoir topographic map, No. 4-D-2246 19

6 Anderson Ranch Reservoir topographic map, No. 4-D-2247 21

7 Anderson Ranch Reservoir topographic map, No. 4-D-2248 23

8 Anderson Ranch Reservoir topographic map, No. 4-D-2249 25

9 Anderson Ranch Reservoir topographic map, No. 4-D-2250 27

10 Anderson Ranch Reservoir topographic map, No. 4-D-225 1 29

11 Anderson Ranch Reservoir topographic map, No. 4-D-2252 31

12 Anderson Ranch Reservoir topographic map, No. 4-D-2253 33

13 Anderson Ranch Reservoir topographic map, No. 4-D-2254 35

14 1998 area and capacity curves 37

111

INTRODUCTION

Anderson Ranch Dam, one of six principal features of the Boise Project, is located in Elmore County

about 28 miles northeast of Mountain Home, Idaho on the South Fork of the Boise River (fig. 1).

Additional principal features are Arrowrock Dam, Black Canyon Dam, Boise River Diversion Dam,

Cascade Dam and Deadwood Dam. Anderson Ranch Dam is the uppermost storage facility on the

Boise system and is 42 miles upstream from Arrowrock Dam. Lucky Peak Dam, built by the Corps

of Engineers, is located about 1 mile upstream from the Boise River Diversion Dam and backs water

up to Arrowrock Dam. Anderson Ranch Dam and Reservoir are owned and operated by

Reclamation and provide benefits in irrigation, power, and flood and silt control.

Anderson Ranch Dam was construction between 1941 through 1950 with first storage on December

15, 1945. A 3-foot parapet wall was added to the top of the dam to provide additional protection

from waves splashing over the top when the reservoir is at or near maximum capacity, elevation

(feet)1 4198.2. The dam is a rolled earth and rockfill structure whose dimensions are (fig. 2):

• Hydraulic height2 332 feet

• Top width 40 feet

• Crest elevation 4,206.0 feet

• Structural height 456 feet

• Crest length 1,350 feet

• Top of parapet wall 4,209.0 feet

The drainage area above Anderson Ranch Dam is 980 square miles, ranging from elevation 3,992.0,

outlet sill elevation, to about 10,000 feet. Anderson Ranch Reservoir has an average width of 0.4

miles with a length, at elevation 3996.0, of around 19.3 miles that includes the main arm and lengths

of all tributaries.

The Anderson Ranch Dam's spillway consists of a concrete-lined chute in the left abutment with two

radial gates each 25 by 22 feet in size. The spiliway crest is at elevation 4,174.0. The spillway gates

provide controllable water storage to elevation 4196.0. The spillway provides a maximum discharge

of 20,000 cubic feet per second (cfs) at maximum reservoir water surface elevation 4,198.2.

The outlet works, with an inlet elevation of 3,992.0, consists of a 20-foot-diameter concrete-lined

tunnel in the left abutment with penstocks in the powerhouse and five 72-inch hollow-jet outlet

valves. The outlet has a discharge capacity of 10,000 cfs.

The powerplant, located to the right of the spiliway, consists of three 90-inch steel penstocks from

the outlet pipes. The discharge capacity is 10,000 cfs at elevation 4,198.0. The powerplant has a

current rated capacity of 40,000 kilowatts with the two installed generators.

1Etevation levels are shown in feet.

2The 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.

1
SUMMARY AND CONCLUSIONS

This Reclamation report presents the 1998 results of the survey of Anderson Ranch 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

Standard land surveying methods were used to establish the horizontal and vertical control points

for the underwater and aerial surveys that were conducted in 1998. The aerial survey was flown in

November of 1998 around reservoir water surface elevation 4178 and the underwater survey was

conducted in June 1998 around reservoir water surface elevation 4196. 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 Anderson Ranch Reservoir. The positioning system provided information to allow the boat

operator to maintain a course along these grid lines. Water surface elevations recorded by a

Reclamation gauge during the time of collection were used to convert the sonic depth measurements

to true reservoir bottom elevations.

The new Anderson Ranch Reservoir topographic maps are a combination of the aerial and

underwater survey data. The 1998 reservoir surface areas at predetermined contour intervals were

generated by a computer graphics program using the collected reservoir data. The 1998 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 Anderson Ranch Reservoir sedimentation and waterhed

characteristics for the 1998 survey. The 1998 survey determined that the reservoir has a total storage

capacity of 474,942 acre-feet and a surface area of 4,743 acres at reservoir elevation 4,196.0. Since

closure on December 15, 1945, the reservoir had an estimated volume change of 18,236 acre-feet

below reservoir elevation 4,196.0. This volume represents a 3.70 percent loss in total capacity and

an average annual loss of 346.7 acre-feet per year.

RESERVOIR OPERATIONS

Anderson Ranch Dam is a multiple-purpose structure that provides irrigation and power benefits,

but also operates in conjunction with Arrowrock and Lucky Peak Reservoirs to provide downstream

flood control. The June 1998 area-capacity tables show 474,942 acre-feet of total storage below

elevation 4,196.0. The 1998 survey measured a minimum elevation of 3886.6. The following values

are from the June 1998 area-capacity tables:

2
• 10,502 acre-feet of surcharge storage between elevation 4,196.0 and 4,198.2.

• 408,442 acre-feet ofjoint use storage between elevation 4,044.0 and 4,196.0.

• 4,632 acre-feet of conservation storage between elevation 4,039.6 and 4,044.0.

• 36,956 acre-feet of inactive storage between elevation 3,992.0 and 4,039.6.

• 24,912 acre-feet of dead storage below elevation 3,992.0.

The Anderson Ranch Reservoir inflow and end-of-month stage records in table 1, operation period

December 1945 through June 1998, show the inflow and annual fluctuation since dam closure. The

estimated average inflow into the reservoir for this operation period was 752,160 acre-feet per year.

Since initial filling, the extreme storage fluctuations of Anderson Ranch Reservoir ranged from an

elevation of 4,007.0 on March 10, 1993 to the maximum recorded elevation of 4,197.98 on June 11,

1983. The records show that in most years the reservoir fills to the near-full reservoir elevation and

annually, while releasing irrigation and power supply water downstream, drops 50 or more feet in

elevation.

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 global positioning system (GPS) receiver with a built-in radio and an omnidirectional

antenna, a depth sounder, a helmsman display fornavigation, a plotter, a computer, and hydrographic

system software for collecting underwater data. Power to the equipment was supplied by an onboard generator.

The shore equipment included a second GPS receiver with a built-in 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 Anderson Ranch Reservoir was Navigation Satellite

Timing and Ranging (NAVSTAR) GPS, an all-weather, radio-based, satellitenavigation 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 detennines 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.

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 receivers 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. For hydrographic surveying, the altitude, Anderson

Ranch's water surface elevation parameter was known, which realistically meant only three satellite

observations were needed to track the survey vessel. During the Anderson Ranch Reservoir survey,

the best available satellites were used for position calculations. Position accuracy was affected due

to the canyon topography of Anderson Ranch Reservoir where at times the visibility of some of the

satellites at one or both of the receivers was blocked.

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 on the radio signal of the ionosphere. 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

Anderson Ranch 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, 1991).

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.

4
A method of collection to resolve or cancel the inherent errors of GPS (satellite position or S/A,

clock differences, atmospheric delay, etc.) is called differential GPS (DGPS). DGPS was used

during the Anderson Ranch 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 isnot 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.

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 receivers programmed position and the

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

For the Anderson Ranch Reservoir, position corrections were determined by the master receiver and

transmitted via a ultra-high frequency (UHF) radio link every 3 seconds to the survey vessel mobile

receiver. The survey vessels GPS receiver used the corrections along with the satellite information

it received to determine the vessels differential location. Using DGPS results in positional

accuracies of 1 to 2 meters for the moving vessel compared to positional accuracies of 100 meters

with a single receiver. During the post-processing of the Anderson Ranch Reservoir collected data,

some positioning errors were found requiring removal or adjusting of the collected data points. It

was concluded that the errors occurred when the two receivers were not simultaneously observing

the same satellites due to the reservoir canyon topography. The system used for this survey didn't

allow the monitoring of the PDOP and FIDOP at the reference GPS receiver. Recent upgrade of the

GPS receivers and software should eliminate this error occurring in the future. The removal and

adjustment of the collected data had very little effect on the total reservoir computed surface areas,

less than 0.1 percent.

The TSC mobile and reference GPS units are identical in construction and consist of a 6-channel Li

coarse acquisition (C/A) code continuous parallel-tracking receiver, an internal modem, and a UHF

radio transceiver. The differential corrections from the reference station to the mobile station are

transmitted using the industry standard Radio Technical Commission for Maritime Services (RTCM)

message protocol via the UHF radio link. The programming to the mobile or reference GPS unit is

accomplished by entering necessary information via a notebook computer. The GPS collection

system has the capability to collect data in 1927 or 1983 North American Datums (NAD) in the

surveyed areas state plane coordinate systems zone. For Anderson Ranch Reservoir, the data were

collected in Idaho's 1983 NAD west state plane zone.

Survey Method and Equipment

The Anderson Ranch Reservoir hydrographic survey collection was conducted on June 24 through

June 28, 1998 at around water surface elevation 4,196. The bathymetric survey was run using sonic

depth recording equipment interfaced with a DGPS capable of determining sounding locations

S
within the reservoir. The survey system software continuously recorded reservoir depths and

horizontal coordinates as the survey boat moved across close-spaced grid lines covering the reservoir

area. Most of the transects (grid lines) were run in a perpendicular direction to the original river

thalweg at 300-foot spacing. Data were also collected along the shore as the boat traversed to the

next transects. The survey vessePs 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. A graphic plotter

was used in the field to track the boat and ensure adequate coverage during the collection process.

The 1998 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 an 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 gage at 15-minute intervals, were used to convert the sonic depth measurements to true

lake-bottom elevations.

RESERVOIR AREA AND CAPACITY

Topography Development

Using ARC,TNFO the topography of Anderson Ranch Reservoir was developed from the combined

1998 aerial and underwater data. ARC/INFO is a software package for development and analysis

of geographic information system (GIS) layers and development of interactive GIS applications

(ESRI, 1992). GIS technology provides a means of organizing and interpreting large data sets.

The 5-foot reservoir contours for elevation 4180 through 4270 were provided by the aerial contractor

as a data exchange format (DXF) file. The underwater contours of the reservoir were developed by

using the elevation 4180 contour as a boundary around the edge of the underwater data set. This

polygon that enclosed the data set was assigned an elevation of 4180.0 and was used to perform a

clip such that interpolation was not allowed to occur outside of this boundary. This clip was

performed using the hardclip option of the ARC/INFO CREATETIN command.

Contours forthe reservoir below elevation 4180.0 were computed from theunderwater data setusing

the triangular irregular network (TIN) surface modeling package within ARC/INFO. A TiN is a set

ofadjacent, non-overlapping triangles computed from irregularly spaced points withx,y coordinates

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

uses a method known as Delaunays 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

6
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 TINC ONTOUR command was used to interpolate

contours from the Anderson Ranch Reservoir TIN. In addition, the contours were generalized by

weeding 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 Anderson Ranch Reservoir since

the areas were calculated from the developed TIN.

ARCiTNFO V7.0.2 GIS software was used to digitize the USGS quad features such as the dam, roads

and the reservoir contour water surface elevation 4196.0. The digitized features were transformed

to Idaho's NAD 1983 west state plane coordinates using the ARC/INFO PROJECT command. The

contour topography at 5-foot intervals is presented on figures 3 through 13 (drawing numbers 4-D2244 through 4-D-2254).

Development of 1998 Contour Areas

The 1998 contour surface areas for Anderson Ranch Reservoir were computed at 5-foot increments,

from elevation 3890.0 to 4,175.0, using the Anderson Ranch Reservoir TIN discussed above. The

1998 survey measured the minimum reservoir elevation at 3886.6 feet. These calculations were

performed using the ARC/INFO VOLUME command. This command computes areas at userspecified elevations directly from the TIN and takes into consideration all regions of equal elevation.

The enclosed surface areas for the 5-foot reservoir contour increments of elevation 4,180.0 through

4,210.0 were measured from the provided DXF aerial contour file.

1998 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 minimum reservoir elevation 3,886.6 to elevation 4,210.0 were used as the

control parameters for computing the Anderson Ranch Reservoir capacity. 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 Anderson Ranch Reservoir. The 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 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:

7
y = a1 + a2x + a3x2

where: y = capacity

x = elevation above a reference base

a1 intercept

- a2 and a3 = coefficients

Results of the 1998 Anderson Ranch Reservoir area and capacity computations are listed in tablel

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

areas and visual capacity. A separate set of 1998 area and capacity tables has been published for the

0.1 and 1-foot elevation increments (Bureau of Reclamation 1998). A description of the

computations and coefficients outputfrom the ACAP85 program is includedwiththesetables. Both

the original and 1998 area-capacity curves are plotted on figure 14. As of June 1998, at elevation

4,196.0, the surface area was 4,743 acres with a total capacity of 474,942 acre-feet.

RESERVOIR SEDIMENT ANALYSES

Figure 14 is a plot of Anderson Ranch Reservoir's original area data versus the 1998 measured areas.

This illustrates the difference between the original and the 1998 measured surface areas. It must

be noted that the original surface areas for the intermediate elevations were interpolated from areas

measured from 50-foot contour topography which was used to develop the original capacity values.

Since Anderson Ranch Dam closure in December 1945, the measured total volume change at

reservoir elevation 4,496.0 was estimated to be 18,236 acre-feet. The estimated average annual rate

of capacity lost for this time period (52.6 years) was 346.7 acre-feet per year. The storage loss in

terms of percent of original storage capacity was 3.70 percent. Tables 1 and 2 contain the Anderson

Ranch Reservoir sediment accumulation and water storage data based on the 1998 resurvey.

The sediment computation values must be questioned due to the interpolation of reservoir area and

resulting capacity values from 50-foot contour intervals, but the resulting value of 346.7 acre-feet

per year appears reasonable when compared to other reservoirs in the region. A resurvey of

Anderson Ranch 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 andReservoirs, 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, June 1998. Denver Office, Anderson Ranch Reservoir Area and Capacity

Tables, Boise Project, Pacific Northwest Region, Denver CO.

Corps of Engineers, March 1991. Application of Differential Global Positioning System for

Hydrographic Survey and Dredge Positioning, Eli 1110-7-5 (FR), Department of the

Army, Washington DC.

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

9
RESERVOIR SEDIMENT

DATA SLARY Anderson Ranch Reservoir

NAME OF RESERVOIR

DATA SHEET NO.

D I. OWNER Bureau of Reclamation 2. STREAM Boise River 3. STATE Idaho

A 4. SEC. 1 TM?. 2 N RANGE 8 E 5. NEAREST P.O. Mountain Home 6. COUNTY Elmore

N 7. LAT 43° 21' 31" LONG 115° 26' 45" 8. TOP OF DAN ELEVATION 4,209.0 9. S?ILLWAY CREST EL 4174.31

R 10. STORAGE 11. ELEVATION 12. ORIG:NAL 13, ORIGINAL 14. GROSS STORAGE 15. DATE

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

S BEGAN

R a. SURCHARGE 4198.2 -- 10,504 503,682

V b. FLOOD CONTROL

_________________ 12/45 0

c. POWER __________________ _____________

R d. JOINT USE 4196.0 4,720 418,191 493,178 16. DATE

e. CONSERVATION 4044.0 1,170 4,987 74,987

f. INACTIVE 4039.6 1,100 41,000 70,000 BEGAN

g. DEAD 3992.0 625 29,000 29,000 12/45

17. LENGTH OF RESERVOIR 19.3- MILES AVG. WIDTH OF RESERVOIR 0.4 MILES

B 18. TOTAL DRAINAGE AREA 980 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION l1.7 INCHES

19. NET SEDIMENT CONTRIBUTING AREA 980 SQUARE MILES 23. MEAN ANNUAL RUNOFF 14.4 INCHES

I 20. LENGTH MILES AV. WIDTH MILES 24. MEAN ANNUAL RUNOFF 752,1606 ACRE-FEET

N 21. MAX. ELEVATION 10000 MIN. ELEVATION 3992 25. ANNUAL TEMP. MEAN 52°F RANGE -23°F to 108°F4

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 AT/AC

P YRS. YRS. INTERVAL

V 12/45 Contour 50-ft 4,720' 493,178' .65

E

Y

0 6/98 52.6 52.6 Contour (D) 5-ft 4,7438 474,942 .63

A

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

SURVEY ANNUAL

_____________________________

PRECI?. a. MEAN ANN. b. MAX. ANN. C. TOTAL a. MEAN ANN. b. TOTAL

6/98 11.7 752,160 1,679,000 38,811,680 752,160 38,811,680

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

SURVEY _____________________________________________________

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

6/98 18,23610 346.7 .35 18,236 346.7 .35

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

SURVEY WT. (#/FT') _______________ _____________________________________________

a. PERIOD

______________

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

6/98 0.070310 3.7010

26. 43. DEPTH DESIGNATION RANGE BY RESERVOIR ELEVATION

DATE

OF

____________________

3992-

___________

4039.6

__________

4080-

__________

4:20-

___________

4160-

__________

4196-

__________ ________________________________________

SURVEY 3886 3992 4039.6 4080 4120 4160

6/98

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

22.2 22.4 15.7 20.0 18.5 1.2

26. 44. REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

DATE 0-10 13- 20- 30- 40- 50- 60- 70- 80- 90- 100- 105- 110- 115- 20-

SURVEY 20 30 40 50 60 70 80 90 100 105 110 115 120 125

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

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

10
45. RANGE IN RESERVOIR OPERATION'

YEAR MAX. ELEV. MIN. ELEV. INFLOW, AF YEAR MAX. ELEV. MIN. ELEV. INFLOW, AF

1946 4,065.6 3,992.0 766,250 1947 4,099.4 3,994.8 645,380

1948 4,101.4 3,994.4 604,140 1949 4,101.3 3,994.6 648,690

1950 4,157.5 4,028.9 842,330 1951 4,196.4 4,143.8 963,690

1952 4,197.0 4,063.0 ,072,140 1953 4,195.7 4,128.3 751,950

1954 4,196.8 4,132.6 716,850 1955 4,190.7 4,132,9 495,620

1956 4,196.0 4,107.7 1,114,660 1957 4,195.9 4,133.3 822,070

1958 4,196.0 4,127.0 906,120 1959 4,195.8 4,164.7 551,420

1960 4,196.0 4,158.3 574,530 1961 4,160.7 4,098.4 375,710

1962 4,196.4 4,058.4 698,590 1963 4,197.8 4,162.4 615,020

1964 4,196.1 4,151.1 592,220 1965 4,196.6 4,128.1 1,305,010

1966 4,195.9 4,149.7 473,030 1967 4,196.4 4,118.2 708,000

1968 4,185,0 4,149.4 461,890 1969 4,195.8 4,132,3 951,260

1970 4,196,0 4,157,4 -- 1971 4,196.9 4,139.4 1,230,000

1972 4,196.1 4,146.1 1,679,000 1973 4,194.4 4,157.0 47.,0Q0

1974 4,195.6 4,129.9 1,126,000 1975 4,193.0 4,152.8 898,000

1976 4,195.4 4,152.2 730,000 1977 4,178.2 4,080.8 226,000

1978 4,196.0 4,080.8 795,000 1979 4,196.0 4,146.8 408,000

1980 4,196.0 4,141.2 747,000 1981 4,196.9 4,162.9 516,000

1962 4,197.5 4,142.4 1,193,000 1983 4,195.8 4,143.6 1,264,800

1984 4,196.8 4,144.7 1,057,470 1995 4,195.7 4,153.8 605,650

1986 4,195.7 4,154.9 1,040,050 1987 4,185.6 4,102.6 327,380

1988 4,146,2 4,093.4 380,350 1989 4,194.0 4,096.5 615,200

1990 4,167.2 4,123.6 402,240 1991 4,142.5 4,079.2 340,000

1992 4,090.6 4,040.6 251,190 1993 4,195.8 4,007.9 717,280

1994 4,168.1 4,064.9 294,190 1995 4,196.5 4,051.6 893,660

1996 4''8: 4,159.5 999.660 1997 4.95.9 4.106,4 3.270.600

1998 4.196.Q_ 4.172.R [ 676.090 t I

46. ELEVATION - AREA - CAPACITY DATA FOR

__

1998 CAPACZ'rY11

____________ _______________ __

-

_____________ _______________

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

3886 0 0 3890 4.0 8 3900 20.8 132

3910 45,9 458 3920 100.8 1,187 3930 166.5 2,516

3940 232.6 4,496 3950 283.9 7,090 3960 336.6 10,173

3970 412.4 13,915 3980 496.5 18,458 3990 564.1 23,770

3992 578 24,912 4000 638.2 29,771 4010 716.2 36,555

4-020 798.5 44,126 4030 905.6 52,619 4039.6 1,023 61,868

4040 1,028.4 62,278 4050 1,158.7 73,226 4060 1,311.8 85,575

4070 1,490.6 99,600 4080 1,674.7 115,411 4090 1,906.0 133,291

4100 2,175,0 153,659 4110 2,425.2 176,653 4120 2,629.7 202,026

4130 2,802.1 229,179 4140 3,078.0 258,425 4150 3,349.4 290,628

4160 3,589.0 325,337 4170 3,878.0 362,615 4180 4,199.4 403,058

4190 4,218.6 447,002 4196 4,743 474,942 4198.2 4,804 485,444

4200 4,853.6 494_,136 4206 5,012 523,735 4210 5l14.7 543,988

47. REMARKS AND REFERENCES

Top parapet wall is elevation 4209.0. Roadway elevation is 4206.0.

2 Spillwa y sill elevation is 4174.0 of radial gates.

Length main arm = 13.3 miles. Length of all tributaries = 6.0 miles.

Bureau of Reclamation Project Data Book, 1981. Reported va lue for all of Boise Project.

Calcula ted using mean annual runoff value of 752,160 AF, it em 24. 6 Computed inflows from l2/45 through 6/98. Missing data for water year 1970.

The or2 ginal areas interpolated from 50-foot contour topogr aphy. Volume at el. 4196 was 493,178 AF reported as

visuall y capacity, 2/15/46.

Surface area & capacity at el. 4196.0. Surface areas at 5- foot intervals measured from 1998 aerial and underwater

survey data. Capacity computed by ACAP program.

Inflow values in acre-feet and maximum and minimum elevatio ns in feet by water year from 12/45 throug h 6/98.

Inflow estimate not available for 1970 .

10 Question as to true original capacity s ince surface areas from 50-foot con tour topography. ' Capacities computed by Reclamation's ACAP computer program.

48. AGENCY S3AK:NG SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation J

DATE September 1999

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

11
1 2 3 4 5 6 7 8

Measured

Elevations Original Original 1998 1998 Sediment Percent of Percent

Area Capacity Area Capacity Volume Computed Reservoir

(feet) (acres) (acre-feet) (acres) (acre-feet) (acre-feet) Sediment Depth

4210 5115 543988

4206 5012 523735

4200 4854 494136

4199 507534 4826 489296 18238 100.0

4198.2 503683 4804 485444 18239 100.0

4196 4720 493178 4743 474942 18236 100.0 100.0

4190 4540 465258 4568 447002 18256 100.1 98.1

4180 4200 421437 4219 403058 18379 100.8 94.8

4170 3920 380975 3878 362615 18360 100.7 91.6

4160 3600 343350 3589 325337 18013 98.8 88.4

4150 3380 308079 3350 290628 17451 95.7 85.2

4140 3140 275071 3078 258425 16646 91.3 81.9

4130 2870 244690 2802 229179 15511 85.1 78.7

4120 2700 216665 2630 202026 14639 80.3 75.5

4110 2510 190515 2425 176653 13862 76.0 72.3

4100 2260 166473 2175 153659 12814 70.3 69.0

4090 1960 145129 1906 133291 11838 64.9 65.8

4080 1720 126407 1675 115411 10996 60.3 62.6

4070 1540 109849 1491 99600 10249 56.2 59.4

4060 1370 95095 1312 85575 9520 52.2 56.1

4050 1205 82084 1159 73226 8858 48.6 52.9

4044 1148 74987 1082 66500 8487 46.5 51.0

4040 1110 70462 1028 62278 8184 44.9 49.7

4039.6 1100 70000 1023 61868 8132 44.6 49.5

4030 1000 59876 906 52619 7257 39.8 46.5

4020 900 50324 798 44126 6198 34.0 43.2

4010 785 41809 716 36555 5254 28.8 40.0

4000 685 34327 638 29771 4556 25.0 36.8

3992 625 29000 578 24912 4088 22.4 34.2

3990 564 23770 33.5

3980 496 18458 30.3

3970 412 13915 27.1

3960 337 10173 23.9

3950 284 7090 20.6

3940 233 4496 17.4

3930 167 2516 14.2

3920 101 1187 11.0

3910 46 458 7.7

3900 21 132 4.5

3890 4 8 1.3

3886 0 0 0.0

1 Elevation of reservoir water surface.

2 Original areas interpolated from areas at 50-foot contour intervals.

3 Original reservoir capacity computed visually.

4 Reservoir surface area from 1998 survey.

5 1998 calculated reservoir capacity computed using ACAP.

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

7 Measured sediment expressed in percentage of total sediment 18,236 acre-feet.

8 Depth of reservoir expressed in percentage of total depth (310.0 feet).

Table 2 Summary of 1998 survey results

12
Figure 1. - Anderson Ranch Reservoir location map.

13
Space intentionally left blank due to security concerns 
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I 7
FigureS. - Anderson Ranch Rcscrvor topographic map. No. 4-D-224( 19
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Figure 6. - Andcrsoii Raiich Reservoir topographic map, No 4-D-2247 21
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wi/Il i/IA/ri

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Fignrc 9. - Andcrson Ranch Rcscrvoir topographic map, No 4-D-225() 27
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Zone

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Figure 1(1, - Anderson Ranch Reservoir topographic map. No. 4-D-225 I 29
W ifE

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Idaho Coordinate System, West Zone

siqi ,t',n

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Figurc I - Anderson Ranch Reservoir topographic map. No. 4-D-2252 31
65O+

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N

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iznxr

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az r_____ _________

Figure H. - Anderson Raiich Reservoir topographic Illap. No. 4-D-2254
Area-Capacity Curves for Anderson Ranch Reservoir

Area (acres)

5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0

4200

4180

4160

4140

4120

4100

4080

4060

4040

w

4020

4000

3980

3960

3940

3920

3900

3880

4200

4180

4160

4140

4120

4100

4080

4060

4040

4020

4000

3980

3960

3940

3920

3900

3880

0 51000 102000 153000 204000 255000 306000 357000 408000 459000 510000

Capacity (acre-feet)

Figure 14. - 1998 area and capacity curves
RECLAMATION' S MISSION

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.