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CASCADE RESERVOIR

1995 SEDIMENTATION

SURVEY

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FOR TFfEp.

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U.S. Department of the Interior

Bureau of Reclamation
REPORT DOCUMENTATION PAGE I Oo'88

Public reporting burden for this collection of information is esttinated to average 1 hour per response, includmg the isne for reviewmg instruofons, sea'thing existing data sources, gathering and

mat'ga*ig the data needed, and comple&lg and reviewing the collection of rifonnation. Sand comments regarding this btxden estdaate or any other aspect of this collection of information, including

suggestions for reI,g this btsden, to Vioigton Heade1ers Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suit 1204, Mington VA 22202-4302,

and to the Office of Management and Budget, Paperwork Reduction Report (0704-0188), Washington DC 20503.

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

May_1998 Final

4. TITLE AND SUBTITLE

______________________________

5. FUNDING NUMBERS

Cascade Reservoir PR

1995 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. DISTRIBUTION/AVAILABIUTY 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 the largest portion of Cascade Reservoir in the fall of 1995 and the

upper area in June 1997 to compile field data for developing a reservoir topographic map and computing a present

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

to sediment accumulation since dam closure in November 1947. The bathymetric survey used sonic depth recording

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

reservoir. The above-water topography was measured from aerial photography obtained in October 1995. The

reservoir topography was developed by a computer graphics program using the 1995 collected data.

As of September 1995, at top of spiliway gate elevation (feet) 4,828.0, the reservoir surface area was 26,307 acres with

a total capacity of 693,123 acre-feet. Since initial filling about 10,329 acre-feet of Cascade Reservoir capacity have

been lost below elevation 4,828.0, resulting in 1.47 percent loss in reservoir volume and a average annual rate of

reservoir capacity lost of 216.1 acre-feet.

Note: The May 1996 report "Cascade Reservoir 1995 Sedimentation Survey" incorrectly reported the reservoir surface

areas (and resulting capacities) due to incorrect reservoir elevations being applied to the 1995 underwater collected

depths. This report includes the elevation correction and also the area-capacity for the portions of the upper reservoir

area surveyed in 1997.

14. SUBJECT TERMS

____________________

15. NUMBER OF PAGES

reservoir area and capacity! sedimentation! reservoir surveys! sonar! sediment distribution! 31

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

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. UMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT

UL UL UL UL

L..

NSN 754OO1-28O-5500 Standard Form 298 (Rev. 2-89

Prsscrlb.d by ANSI Std. 239-1

298-102
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CASCADE RESERVOIR

1995 SEDIMENTATION SURVEY

by

Ronald L. Ferrari

Sedimentation and River Hydraulics Group

Water Resources Services

Technical Service Center

Denver, Colorado

May 1998
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ACKNOWLEDGMENTS -

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

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the Technical Service Center (TSC) prepared and published this report. Ronald Ferrari was

the TSC team leader and conducted the hydrographic survey. James Melena of the TSC and

Doug Saint from the Pacific Northwest Region assisted during the 1995 bathymetric survey.

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Personnel from the Columbia Basin Project Office performed the required land survey for

the hydrographic and aerial data collection. George "Al" Knight of the Mid-Pacific Region

conducted the aerial photography interpretation. Ronald Ferrari completed the data

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processing needed to generate the new map topology and area-capacity tables. Sharon

Nuanes of TSC completed the contour digitizing and edge matching of the U.S. Geological

Survey maps of the reservoir for the above water topographic development. Ron Ferrari and

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Sharon Nuanes composed the final maps presented in this report. Cassie Klumpp of the TSC

performed the peer review of this documentation.

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U.S. Department of the Interior

Mission Statement

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.

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The information contained in this report regarding commercial products or firms may not be

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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 Reclamation; no warranty as to

its accuracy, usefulness, or completeness is expressed or implied.

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CONTENTS -

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Introduction 1

Summary and conclusions 2

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Reservoir operations

Hydrographic survey equipment and method

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GPS technology and equipment 4

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Survey histoiy

Survey methods

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Reservoir area and capacity 7

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Topography development 7

Development of 1995 contour areas 8

1995 storage capacity 8

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Reservoir sediment analyses 9

References 10

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TABLES

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Table

1 Reservoir sediment data summary (page 1 of 2) 12

1 Reservoir sediment data summary (page 2 of 2) 13

2 Summaryofl995surveyresults 14

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FIGURES I

Figure

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Cascade Reservoir location map

Cascade Dam, plan and section

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3 Cascade Reservoir survey data 17

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Cascade Reservoir topology map, No. 3-D-2813

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asca e Reservoir topology map, No. 3-D-2814 21

6 Cascade Reservoir topology map, No. 3-D-2815 23

7 Cascade Reservoir topology map, No. 3-D-2877 25

8 Cascade Reservoir topology map, No. 3-D-2878 27

9 Cascade Reservoir topology map, No. 3-D-2879 29

10 1995 area and capacity curves 31

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INTRODUCTION -

Cascade Dam and Reservoir are the largest storage facilities of the Boise Project. The dam, located

in Valley County, Idaho on the North Fork of the Payette River is approximately 0.5 mile northeast

of Cascade and 60 miles north of Boise, Idaho (fig. 1).

Dam closure and first reservoir storage began on November 7, 1947. The multi-purpose reservoir

provides primarily irrigation storage with additional storage for power generation and flood control.

The original reservoir survey measured a surface area of about 26,487 acres at the reservoir's full

pool and top of spillway gate elevation 4,828.0 (feet)1. The original calculated total capacity at

reservoir elevation 4,828.0 was reported as 703,200 acre-feet, of which 50,000 acre-feet was inactive

storage (Bureau of Reclamation, 1981). At elevation 4,828.0 the reservoir length is around 20.8

miles and has an average width of around 0.5 miles.

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The reservoir regulates flow for Black Canyon Dam powerplant and serves as an irrigation supply

for the Payette Division and the Emmett Irrigation District. Reclamation operates and maintains the

facility, which, on an informal basis, provides flood control of the Payette River through Horseshoe

Bend, Idaho. Reclamation recently committed to use uncontracted reservoir storage to maintain a

minimum pool for maintenance of water quality and resident fisheries, and for downstream flow

augmentation to assist in the salmon recovery (Bureau of Reclamation, 1995a).

The watershed above Cascade Reservoir, located in the western slope of the Sawtooth Mountains,

is 620 square miles, of which 208 square miles is considered non-contributing because the upstream

reservoirs being effective sediment traps. Payette Lake (drainage area = 144 square miles) and Lake

Fork Reservoir (drainage area =64 square miles) control the inflow. Basin elevations range from

4,787.5 (minimum allowable pool elevation) to 8,960 (Nick Peak) in Lake Fork of the Payette

drainage above Lake Fork Reservoir. Most of the peaks bordering the watershed exceed elevation

7,000 feet; the mean elevation is 5,960.

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Cascade Dam is a zoned earthfi 11 structure (fig. 2) with:

• a structural height2 of 107 feet

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. a hydraulic height of 75 feet

• a crest elevation of 4840.0 feet

• atop crest width of 35 feet

• a crest length of 785 feet

1A1l elevations (vertical datum) based on U.S. Bureau of Reclamation levels that are 0.66

feet higher than U.S. Coast and Geodetic Survey datum.

2The definition of such terms as "structural height," "hydraulic height," etc. may be

found in such manuals 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.

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Cascade Dam's spillway has a crest elevation of 4,808.0 with an elevation of 4,828.0 at the top of

the radial control gates. At elevation 4,828.0 the maximum capacity is 12,000 cubic feet per second

(ft3lsec). The spiliway, located on the right abutment of the dam, consists of:

• an inlet channel

• a overflow weir crest and bridge pier

• a spiliway bridge

• a concrete chute

• terminal flipbucket

• two 21- by 20-foot radial gates

The river outlet works is located on the right abutment, has a capacity of 2,530 ft3/sec at elevation

4828.0, and consists of:

• an intake structure with 12-foot by 13.4-foot fixed-wheel gate

• 1 2-foot-diameter concrete-lined pressure tunnel

• 12-foot-diameter steel pipe encased in concrete

• control house with two 5- by 5-foot high pressure gates

• two 84-inch-diameter steel outlet pipes

SUMMARY AND CONCLUSIONS

This Reclamation report presents the 1995 results of the first extensive survey of Cascade Reservoir

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

• develop reservoir topography

• compute area-capacity relationships

• resolve conflicts about storage capacity

• estimate storage depletion caused by sedimentation deposition since closure of Cascade

Dam.

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

GPS (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 Cascade Reservoir. The positioning system provided information to allow the

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

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

to true lake bottom elevations.

The above-water Cascade Reservoir area was measured from aerial photography obtained in October

of 1995. Photo interpretation produced horizontal positioning and elevations throughout the

reservoir area. The new reservoir contour map is a combination of the aerial and underwater survey

data. The 1995 reservoir surface areas at predetermined 2-foot contour intervals were generated by

a computer graphics program using the collected data. The 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).

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

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characteristics for the 1995 survey. The 1995 survey determined that the reservoir has a total storage

capacity of 693,123 acre-feet and a surface area of 26,307 acres at water surface elevation 4828.0.

The difference between the recomputed original and the 1995 capacities, at reservoir elevation

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4828.0, indicated a volume of 10,329 acre-feet of sediment has accumulated since dam closure in

November 1947. This volume represents a 1.47 percent loss in total capacity and an average annual

loss of 216.1 acre-feet per year. All elevations in this report are based on U.S. Bureau of

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Reclamation levels that are 0.66 feet higher than the U.S. Coast and Geodetic Survey datum.

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RESERVOIR OPERATIONS

The reservoir is a multiuse facility having (following values are from September 1995 area-capacity

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tables):

• 156,281 acre-feet of surcharge storage between elevations 4,828.0 and 4,833.6.

• 646,461 acre-feet of conservation storage for irrigation, power generation and flood control

between elevations 4,787.5 and 4,828.0.

• 46,662 acre-feet of inactive and dead storage below elevation 4,787.5.

I Cascade Reservoir receives the majority of its inflow from the north fork drainage of the Payette

River. Available records for calendar years 1947 through 1995 show that the average inflow into ; the reservoir was 732,550 acre-feet per year. This inflow computes to a mean annual runoff of 22.2

= inches for the 620-square mile basin. The inflow and end-of-month stage records in table 1 show

the annual fluctuation of the reservoir. After initial filling to spillway gate elevation 4828.0 in July

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1957, available records show Cascade Reservoir operation ranging from elevation 4,802.2 on

February 8, 1962 to elevation 4,828.9 in June 10 and 11 of 1957.

HYDROGRAPHIC SURVEY EQUIPMENT AN]) METHOD

The hydrographic survey equipment was mounted in the cabin of a 24-foot tn-hull 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 omnidirectional antenna, dual frequency depth

sounder, helmsman display for navigation, plotter, computer, and hydrographic system software for

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

The shore equipment included a second GPS receiver with a built-in radio and omnidirectional

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

The power for the shore units was provided by a 12-volt battery. To obtain the maximum radio

transmission range, known datum points with clear line-of-sight to the survey boat were selected.

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The 1997 survey of the upper underwater reservoir area was conducted with the same system, but

a portable depth sounder allowed the system to be powered by 12-volt batteries and mounted in a

12-foot flat bottom boat.

GPS Technology and Equipment

The positioning system that was used at Cascade Reservoir was Navigation Satellite Timing and

Ranging (NAVSTAR) GPS, an all weather, radio based, satellite navigation system that enables

users to accurately determine 3-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 Department of Defense (DOD). The GPS receiver

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

the 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 precise orbits about 10,900

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

• The ground control segment tracks the satellites, determining their precise orbits, and

periodically transmits correction and other system data to all the satellites, then retransmitted

to the user segment.

• The user segment is the GPS receivers that measure the broadcasts from the satellites and

calculates 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 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 "U' band frequencies for

the distance measurement signals called Li and L2. A minimum of 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 or the Cascade Reservoir water surface elevation parameter was known, which realistically

meant only three satellite observations were needed to track the survey vessel. During the Cascade

Reservoir survey, a minimum of five satellites were used for position calculations. Most of time,

the best six available satellites were used.

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

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

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

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on the radio signal by 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 (PDOP) (x,y,z), and horizontal

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dilution of precision (H1)OP) (x,y). The components are based only on the geometry of the

satellites. The PDOP and HDOP were monitored during the Cascade Reservoir Survey, and for the

majority of the time, they were less than 3, which is within the acceptable limits of horizontal

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accuracy for Class 1 and 2 level surveys (Corps of Engineers, 1991).

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An additional and larger error source of 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

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can have errors of up to 100 meters.

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

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clock differences, atmospheric delay, etc.) is called DGPS. DGPS was used during the Cascade

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 the two units,

which are simultaneously observing the same satellites. The inherent errors are mostly canceled

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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

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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.

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For the Cascade Reservoir Survey, position corrections were determined by the master receiver and

transmitted via a UHF radio link every 3 seconds to the survey vessel mobile receiver. The survey

vessel's GPS receiver used the corrections along with the satellite information it received to

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determine the vessel's differential location. Using DGPS resulted in positional accuracies of 1 to 2

meters for the moving vessel compared to positional accuracies of 100 meters with a single receiver.

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 U}{F radio link. The programming to the mobile or reference GPS unit is

accomplished by entering necessary information via a notebook computer. The IS C's GPS system

has the capability of establishing or confirming the land base control points by using notebook

computers for logging data and post-processing software. The GPS collection system has the

capability of collecting data in 1927 or 1983 North American Datums (NAD) in the surveyed area's

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state plane coordinate system's zone. For the 1995 Cascade Reservoir survey, the state plane

coordinate system used was 1983 NAD in Idaho's West Zone.

Survey History

The original Cascade Reservoir area and capacity curves, dated August 7, 1950, were presented on

drawing 3-100-140. The drawing notes indicate that the data for the curves were from drawing 3-D1666, dated October 30, 1944. No other information on surface area and contour development was

located. It is assumed the original surface areas were obtained by a planetable survey, prior to dam

closure, at a 5-foot contour accuracy. The original surface area values from the 1944 drawing are

listed in column (2) of table 2. Column (3) gives the original capacity of Cascade Reservoir

recomputed using the area-capacity computer program ACAP (Bureau of Reclamation, 1985).

Survey Methods

The Cascade Reservoir hydrographic survey was completed using the contour method as outlined

by Blanton (1982). The procedure involved collecting adequate coordinate data for developing a

reliable contour map by bathymetric and aerial survey methods. The bathymetric survey used sonic

depth recording equipment interfaced with GPS positioning that gave continuous sounding positions

throughout Cascade Reservoir.

Reclamation's Columbia Basin Project Office personnel used GPS equipment and standard land

surveying methods to establish horizontal and vertical control points for the hydrographic survey.

The above-water data were collected by aerial photography obtained in October 1995 at approximate

reservoir elevation 4824.7 feet. Reclamation's Mid-Pacific Regional office conducted the aerial

photography interpretation and provided coordinated data at 200-foot cross section intervals to

define the reservoir topography. The aerial data set includes 44,196 coordinate points.

The Cascade Reservoir bathymetric survey was conducted in 1995 and 1997. In 1995 the survey

started on August 28, 1995 and concluded on September 4, 1995 at reservoir water surfaces ranging

from elevation 4826.3 to 4826.8. The 1997 survey was conducted on June 20 and 21 at reservoir

water surface elevation 4,827.4. The bathymetric surveys were run using sonic depth recording

equipment interfaced with a DGPS capable of determining sounding locations within the reservoir.

The survey system software was capable of recording depths and horizontal coordinates in 1-second

increments as the survey boat moved along predetermined gridlines covering the reservoir.

To produce adequate data for developing contours of Cascade Reservoir, grid lines or transects

accessible by the survey boat were collected at a spacing of 150 meters in a mostly east-west

alignment. Transects were also run in a mostly north-south alignment at a spacing of around 500

meters. Data were collected at an average of 2-second intervals with additional data collected along

the shore as the boat traversed to the next transect. The survey vessel's guidance system gave

directions to the boat operator to assist in maintaining course along these predetermined gridlines.

During each run, the depth and position data were recorded on the notebook computer bard drive for

subsequent processing by TSC personnel.

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A graphic plotter was used in the field to track the boat and ensure adequate coverage during the

collection process. The underwater data set included 115,316 coordinate points. Water surface

elevations recorded by a Reclamation gage at the dam were used to convert the sonic depth

measurements to true lake bottom elevations. In 1995 boat access problems above Tamarack Falls

Road prevented surveying of a small portion of the reservoir on the North Fork of the Payette River

and on the Lake Fork Ann. These areas were surveyed in 1997 using a small flat bottom boat.

Appending all the data sets gave a total of 159,512 coordinate points for contour development as

illustrated on figure 3.

The TSC's depth sounder has a 208-kilohertz transducer that reflects off the first bottom surface.

This surface represents the top of the accumulated sediment for the reservoir survey. The bottom

is determined by measuring elapsed time between the transmission of the sound pulse from the

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transducer to the waterway bottom and the reception of its echo back to the transducer. Prior to data

collection and periodically through the survey, the depth sounder was calibrated by lowering a

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

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

temperature, turbidity, and other conditions. The accuracy of an instantaneous reading from the

depth fmder is estimated to be ±0.5 feet, which takes into consideration calibration error and data

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collection in a moving boat. The collected data was digitally transmitted to the computer collection

system via a RS232 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

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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 ifies were modified. Problems with the digital records were encountered in the areas

of the reservoir that were heavily vegetated. These areas were encountered periodically throughout

the reservoir, mainly in depths of 12 feet or less. In the majority of these cases, the analog charts

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were utilized to determined the true lake bottom, and the computer files were modified to reflect the

analog chart values.

RESERVOIR

AREA AND CAPACITY

Topography Development

The topography of Cascade Reservoir was developed from the combined 1995 aerial, and the 1995

and 1997 underwater collected data. The upper contours of the reservoir were developed by

digitizing a boundary around the edge of the 1995 collected data that covered the reservoir area.

From the USGS (U.S. Geological Survey) quad maps, the roads, railroads, towns, and other features

that cover the reservoir area were digitized. ARC/INFO V7.0.2 Geographic Information System

software was used to digitize the USGS quad map features and the boundary or polygon that

enclosed the collected data. The digitized information was transformed to state plane coordinates,

NAD 1983, using the ARC/INFO PROJECT command (ESRI, 1992).

Contours for the reservoir area were computed from the collected data using the triangular irregular

network (TIN) surface modeling package within ARC/INFO. The horizontal datum of the survey

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data was based on Idaho's state plane west zone coordinates in NAD 1983. The vertical datum is

based on U.S. Bureau of Reclamation levels that are 0.66 feet higher than the U.S. Coast and

Geodetic Survey datum. The collected data ranged in elevation from around 4760 feet for the

underwater data to greater than 4845 feet for the aerial data. A TIN is a set of adjacent, nonoverlapping 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 know as Delaunay's criteria for triangulation. Triangles are formed

between all collected data points including all boundary points. This method preserves all collected

survey points. The method requires that a circle drawn through the three nodes of a triangle will

contain no other point. This requirement means that sample points are connected to their nearest

neighbors to form triangles. Using the hardclip option of the ARC/INFO CREATETIN command,

a clip or polygon boundary of the study area was developed. The digitized polygon enclosing the

collected data was assigned an elevation of no data and was used to perform the clip of the Cascade

Reservoir TIN such that interpolation was not allowed to occur outside the boundary. The elevation

contours are interpolated along the triangle elements. The TIN method is discussed in great detail

in the ARC/INFO V7.0.2 Users Documentation (ESRI, 1992).

Island contours occurred in the lower reservoir area from the dam upstream throughout the reservoir.

This condition occurred because of the meandering stream of the original river channel. The contour

program could have completed the meandering channel contours if the area was saturated with

additional data. It is assumed that the computed island areas for these elevations are only slightly

less than if the contour were one enclosed area. These areas are a very small percentage of the

overall reservoir area and have little effect on the overall volume computations.

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

contours from the Cascade 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 Cascade Reservoir because the

surface areas were computed from the developed TIN, which used all collected data points. The

contour topography at five-foot intervals is presented on figures 4 through 9 (maps No.3-D-2813

through 3-D-2815 and 3-D-2877 through 3-D-2879).

Development of 1995 Contour Areas

The 1995 contour surface areas for Cascade Reservoir were computed in 1-foot intervals from

elevation 4760.0 to 4845.0 using the Cascade Reservoir TIN discussed above. These calculations

were performed using the ARC/INFO VOLUME command. This command computes areas at user

specified elevations directly from the TIN and takes into consideration all regions of equal elevation.

1995 Storage Capacity

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

area-capacity computer program ACAP (Reclamation, 1985). The 1995 surface areas at 2- and 5-

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foot contour intervals from elevation 4,759.2 feet to 4,840.0 feet were used as the control parameters

for computing the Cascade 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 0.000001 for Cascade

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:

I

where:

y = a + a2x + a3x2

y = capacity,

x = elevation above a reference base,

a = intercept, and

* a2 and a3 = coefficients

I

Results of the 1995 Cascade Reservoir area and capacity computations are listed in table 1 and 2 and

plotted on figure 10. A separate set of 1995 area and capacity tables was published for the 0.01-,

g

0.1-, and 1 -foot elevation increments (Bureau of Reclamation, 1 998b). These tables include a

description of the computations and coefficients output from the ACAP program. Computation

results are listed in columns (4) and (5) of table 2. Column (2) gives original measured contour areas

I

used in the original area and capacity computation, and column (3) gives original capacity

recomputed using ACAP. Both the original and 1995 area and capacity curves are plotted on figure

10. As of September 1995, at spillway crest elevation 4828.0 feet, the surface area was 26,307 acres

with a total capacity of 693,123 acre-feet.

I

RESERVOIR SEDIMENT ANALYSES

Reservoir sediment survey data for Cascade Reservoir are shown in tables 1 and 2. The computed I

volume difference between the original (1947 survey) and 1995 measured reservoir capacities for

Cascade Reservoir is 10,329 acre-feet below top of spillway gate elevation 4,828.0. The average

annual rate of lost capacity was 216.1 acre-feet per year, or 0.52 acre-foot per square mile from the

sediment contributing drainage area of412 square miles. The storage difference in terms of percent

of original storage capacity was 1.47 percent.

I The 1995 sediment calculations were based on the difference between the original and the 1995

measured reservoir capacities. The elevations for both the original and 1995 surveys were based on

the U.S. Bureau of Reclamation vertical datum that is 0.66 feet higher than the U.S. Coast and

Geodetic Survey datum. This method accounts for the sediment accumulation during the 47.8 years

9
of reservoir operation, but the calculations are only as accurate as the two surveys. It is assumed that

a portion of the 0.52 acre-foot per square mile yield rate is attributable to the different survey

collection methods.

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, 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, Finding of No Signfl cant Impact and Final Environmental Assessment:

Management of the Uncontracted Storage Space in Cascade and Deadwood Reservoirs, Fayette

Division Boise Project, Idaho, Snake River Area Office, Pacific Northwest Region, Boise ID,

February 1995.

Bureau of Reclamation, Denver Office, "Cascade Reservoir Area and Capacity Tables, Fayette

Division," Pacific Northwest Region, Denver, CO, May 1998b.

Corps of Engineers, Application of Differential Global Positioning System for Hydrographic Survey

and Dredge Positioning, ETh 11 l0-7-5(FR), Department of Army, Washington DC, March 1991.

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

10
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RESERVOIR SEDIMENT

DATA SUMMARY Cascade Reservoir

NAME OF RESERVOIR

1

DATA SHEET NO.

0 1. OWNER Bureau of Reclamation 2. STREAM N. Fayette River 3. STATE Idaho

A 4. SEC. 26 TWP. 14N RANGE 3E 5. NEAREST P.O. Cascade 6. COUNTY Valley

M 7. LAT 44' 31' 30" LONG 116' 03' 00" 8. TOP OF DAM ELEVATION 4,840 9. SPILLWAY CREST EL. 4,808

H 10. STORAGE 11. ELEVATION 12. ORIGINAL 13. ORIGINAL 14. GROSS STORAGE 15. DATE

E STORAGE

a. SURCHARGE 4,833.6 157,000 860,000 BEGAN

E

H

b. FLOOD CONTROL

11/07/ 7

v

C. POWER

4

o d. WATER SUPPLY 16. DATE

I e. IRRIGATION NORMAL

H f. CONSERVATION 4,828.0 26,487 653,000 703,000 OPERATION

g. INACTIVE 4,787.5 50,000 50,000 06

17. LENGTH OF RESERVOIR 20.8 MILES AVG. WIDTH OF RESERVOIR 0.5 MILES

B 18. TOTAL DRAINAGE AREA 620 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 22552 INCHES

A 19. NET SEDIMENT CONTRIBUTING AREA 412' SQUARE MILES 23. MEAN ANNUAL RUNOFF 22.2' INCHES

20. LENGTH MILES AV. WIDTH MILES 24. MEAN ANNUAL RUNOFF 732,550 ACRE-FEET

__

21. MAX. ELEVATION 8960 MIN. ELEVATION 4787.5 25. ANNUAL TEMP. MEAN 41.3'F RANGE -40'F to 100°F'

5 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 AX/Ar

R __________________ ________________ ____________________________________________________

V 11/47 Contour CR)5 5-ft 26,487 703,452 0.96

E

Y 9/95 47.8 47.8 Contour CD) 5-ft 26,307 693,123 0.95

D

A

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

___________________________________

WATER INFLOW TO DATE, Ar

T

EVEY ANNUAL

A

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

9/95 22-55 732,550 1,328,888 35,162,380 732,550 35,162,380

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.

9/95 10,329'' 216.1' 0.52 10,329 216.1 0.52

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

SURVEY MT. {#/FT') ____________________________

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

9/95 0.031' 1.47'

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

DATE

68.0- 48.0- 38.0- 28.0- 18.0- Crest- CrestSURVEY

48.0 38.0 28.0 18.0 8.0 -8.0 .5.6

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

9/95 25.1 10.3 18.8 7.0 10.6 25.5 2.7

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

DATE 0-10 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 105- 110- 115- 120-

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).

12
45. RANGE IN RESERVOIR OPERATIONS

YEAR MAX. ELEV. MIN. ELSV. INFLOW • AR YEAR MAX. ELEV. MIN. ELEV. INFLOW, AF

1947 865,695 1948 874,693

1949 722,153 1950 793,334

1951 4,800.7 4,790.0 803,988 1952 4,812.1 4,792.8 987,022

1953 4,814.6 4,792.3 769,254 1954 4,814.9 4,796.3 792,440

1955 4,814.8 4,795.5 540,598 1956 4,822.5 4,799.8 995,215

1957 4,828.0 4,811.3 817,299 1958 4,828.0 4,810.8 769,738

1959 4,827.8 4,815.4 677,033 1960 4,828.1 4,814.4 686,856

1961 4,826.2 4,806.4 582,526 1962 4,826.8 4,802.8 647,808

1963 4,828.3 4,817.7 832,375 1964 4,828.0 4,811.8 719,800

1965 4,827.8 4,815.4 1,066,654 1966 4,827.4 4,809.1 482,285

1967 4,827.0 4,799.4 759,889 1968 4,826.5 4,812.2 575,346

1969 4,828.0 4,806.4 815,959 1970 4,828.3 4,809.4 856,338

1971 4,828.4 4,809.1 1,116,065 1972 4,827.5 4,807.3 858,821

1973 4,824.4 4,808.4 438,772 1974 4,828.4 4,807.0 1,328,888

1975 4,826.2 4,809.5 746,733 1976 4,827.8 4,813.1 897,415

1977 4,819.0 4,803.8 221,788 1978 4,827.6 4,804.6 943,230

1979 4,824.5 4,809.3 447,275 1980 4,827.8 4,805.6 774,141

1981 4,828.3 4,814.4 736,928 1982 4,828.2 4,813.2 1,185,059

1983 4,827.2 4,816.2 1,040,516 1984 4,827.7 4,817.2 953,386

1985 4,827.5 4,815.6 563,591 1986 4,827.7 4,815.2 820,936

1987 4,825.1 4,813.3 349,450 1988 4,823.7 4,812.0 370,503

1989 4,827.2 4,813.4 597,508 1990 4,827.8 4,817.1 488,844

1991 4,827.5 4,817.3 417,388 1992 4,823.3 4,813.0 344,958

1993 4,827.8 4,810.6 754,770 1994 4,824.5 4,811.0 298,885

1995 4.828.0 4811.2 897.911

______________ _____

46. ELEVATION - AREA - CAPACITY DATA FOR 195 CAPACITY

__________ - _______________ ______________

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

4759.2 0 0 4764 11 16 4768 95 196

4772 634 1,427 4776 1,580 5,853 4780 2,836 14,405

4784 4,397 28,889 4787.5 5,837 46,662 4792 7,983 77,679

4796 10,274 114,299 4800 12,437 159,714 4804 14,295 213,314

4808 16,101 274,142 4812 17,894 342,155 4816 19,804 417,353

4820 22,062 501,099 4824 23,692 592,716 4828 26,307 693,123

4832 28,587 802,947 4833.6 29,484 849,404

47. REMARKS AXE) REFERENCES

Top of spillway radial gates elevation 4828.0, spillway crest elevation 4,808.0. All elevations based on the

U.S. Bureau of Reclamation vertical datum that is is 0.66 feet higher than t he U.S. Coast and Geodetic Survey

datum.

Bureau of Reclamation Probable Maximum Flood Study, April 1987.

Represents loss of sediment contributing areas behind Payette Lake (144 mi) and Lake Fork (64 mi3).

Calculated using mean annual runoff value of 732,550 AR, item 24.

Surface area-capacity at elevation 4828.0, recomputed by Reclamation's ACAP program using original surface areas.

Surface area values from Reclamation drawing No. 3-D-1666.

Total capacity loss calculated by comparing original recomputed capacity and 1995 capa city at reservoir elevation

4828.0. Portion of lost due to different methods of collection.

Portion of computed storage lost due to different method of measuring reservoir areas. Original surface area

values projected from area curve.

End-of-month maximum and minimum elevations by water year, inflow values by calendar year.

Not.: Area-capacity tables updated in 9/97 to account for reservoir elevation datum adj ustment used to convert

1995 underwater collected data and to account for areas of upper reservoir not surveyed in 1995. All

elevations based on the U.S. Bureau of Reclamation vertical datum that is 0.66 feet higher than the U.S.

Coast and Geodetic survey datum.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation DATE May 1998

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

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(1)

Elevation

(feet)

(2)

Original

Area

(acres)

(3)

Original

Capacity

(acre-feet)

(4)

1995

Area

(acres)

(5)

1995

Capacity

(acre-feet)

(6)

Measured

Sediment

Vohre

(acre-feet)

(7)

Percent

Measured

Sediment

(8)

Percent

Reservoir

Depth

4840.0 32.967 L059.857 32.909 1.049.146 - - -

4835.0 30.246 901.824 30.260 891.228 - - -

4833.6 (29,479)* 860.017 (29.484) 849.404 10.613 100.0 100.0

4830.0 27.506 757.444 27.466 746.895 10.549 99.4 95.1

4828.0 (26,487) 703.452 26.307 693.123 10.329 97.3 92.4

4825.0 24.958 626.284 24.512 616.819 9.465 89.2 88.3

4820.0 22,070 508.714 22.062 501.099 7.615 71.8 81.5

4815.0 19.371 405.112 19.245 397.828 7.284 68.6 747

4810.0 17,174 313.750 17.009 307.252 6,498 61.2 67.9

4805.0 14,807 233.797 14.746 227.835 5.962 562 61.1

4800.0 12.526 165.464 12.437 159,714 5.750 54.2 54.3

4795.0 10.014 109.114 9.731 104.297 4.817 45.4 47.6

4790.0 7.051 66.452 6.998 - 62.698 3.754 35.4 40.8

4787.5 (5.938) 50.216 (5.837) 46,662 3.554 33.5 37.4

4785.0 4.824 36.764 4.744 33,459 3.305 31J 34.0

4780.0 3.053 17.072 2,836 14.405 2,667 25.1 27.2

4775.0 1.536 5.600 1,364 4.381 1.219 11.5 20.4

4770.0 391 782 251 542 240 23 136

4766.0 0 0 39 62 - . 82

4765.0 ___________ ' 22 32 - 6.8

4759.2 - - 0 0 0.0

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(1) Elevation of reservoir water surface based on U.S. Bureau of Reclation vertical datir that is 066 feet higher

than the ILS. Coast and Geodetic survey datLil.

(2) Original reservoir surface areas from Reclnation drawing 3-0-1666.

(3) Original calculated reservoir capacity c*xputed using ACAP from original measured surface areas.

(4) Reservoir surface area from 1995 and 1997 survey.

(5) 1995 calculated reservoir capacity cputed using ACAP, from 1995 and 1997 measured surface areas.

(6) Measured sediment vole - colt (3) coln (5).

(7) Measured sediment expressed in percentage of total sediment 10,613 acre-feet at elevation 4833.6.

(8) Depth of reservoir expressed in percentage of total depth (73.6 feet).

* Areas in ( ) ccuted by frCAP.

I Table 2. - Suinary of 1995 survey results.

14
/ 1 / ) McCtII

V

Council IRRIGABLE AREA

/

CASCADE

RESERVOIR

Ca. de

CRANE CREE(J // DEADWOOD

C' RFSE OIR - 1-' RESERVOIR

Veiser

. /

WASH iNGION ( I

(

CuS/TR -

___

/

_

I

-____ --

I

'

f -

P A Y j/T E I Lowman

avette /

G E M

•

LACL CAJTYOJ( DAM _L

42'D POWf.Bpf -

- . I4O5(SNO€ e€No

• GAGING STATION

az..&cx cAwyo/1r

- -:EF( ett I

-

--- B 0 I S E

ADA -

RIVER LUCKY PEAK

- --: RESERVOIR

\k Lel BO1SF (CE)

- :•. ARROWROCK

n RESERVOIR

/

0 0

CA NYON /

S Murphy1

SCALE OF MILES

10 5 0 tO

.or.SE irvzJ

yEAS oN DAM

E LMORE ANDERSON RANCH

RESERVOIR

n Home

Figure 1. - Cascade Reservoir location map.

15
Space intentionally left blank due to security concerns 
,..

.

U Iuhij.L!IlI

--4.----

• •;:.;.r1!

:i! !t;.::I

b

- •.••--•

•;,__•:

I

.1iII_ •_I

I

Figure 3. - Cascade Reservoir survey data.

17
'I,

N'

NH

I.:;

040000-

io

HotizOstal Oatum Based on iduhos

State Plane Zone WCt 660 8)

Vertical Ostum Based on U S Bureau

of Reclam.itton Levels That are 066

Feet Higher Than U.S Coast and

Geodetic Survey Oetue

Cascade

Oam

Cascade

( \

(

ç1

'_0t

(IIIv

N

w I

S

1#!

IIW W W

fyte onigfnal map dated Ao,rl 2. 1596

Contours redrawn due to elevation datum adlustrT40nt

(5t1t i'EsERfl2/#

______ia*i 4

Mw', ,/#f* 4 . IM J j.'-ätJ

ngure 4. - *SC*GC Keservoir topology map, No. 3-]

Match to Drawing 814

19
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Match to Dr'aWthQ 3-0-2015

c1

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Put

fW *V LW -í

1⁄4 /

J0

4

A

/

- '0

i4o.-i050te! Oatue BAsed On dahoe 4

Stete Pene Zone We8t /NAD BA)

AtiCal toe Sed On U.S. BeAu

4i

'4 ______________________________________

o ISecleeation Levels 1ht Are 0.66

K J rise or me) .O dAred April 24. 1596

Feet Higrier Then U.S. Coast afld Contour! redresn doe to eleretlon O.tue oci/o$tmer.t

_________________________________________________

GeodetIc Surrey Oatue

.

(5

A,

aew,r_______ jv.iqait mia

Match to Drawing

_____ __________

3-0-2813

!'4 4W my J r.

Figure 5.- Csscade Reservoir topology map No. 3-1)2814.
N

w

Lont&) O.tur. Baaed on lOaSos

Stete Pl.oe lone Went (NAG 63)

Vertical Datum BOneO 0fl U S Bureau

of clamatlorf Leoeln That Are

Feet Higher tOan U S. COa

E

Geode tic Sorvay Gatum

Match to Drawing 3-0-2816

il7 01

/

'

/ I)

:

i-ç çt

,/ (

q /

A

(\,

U

II

4/ 2

o /

/

/ Sugar

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_1

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7

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0000+ j +

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11

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0000-1- /

I'

7 -

-I,_ I.J

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JI1

Match to Dr8wing 3-0-2814

6eoise oriQii-ial f8P doted AGrOI 24, 1996

COntoui- redrawr joe to ele,etlon datum ad)ustmnnt

;J asqi IESERVOI4'

air______ ______ a',-

______

Awp% /wWQ /$

FiEure 6. - Cucade Reservok topology map, No. 3-D-2815.
NN

iiNNNN

PNI

e tw a*v .w

25

flOI.LIt LI' '"W -

Fture 7. - Cascade Keser'oIr topoIoy map No. 3-U-2877.
IIIIIII1IIIIIII N w

E

S

e iiw

W

W

27

rigure 5. - acaae eservoir wpoiogy map, rw. .'-JP-&o 10.
IIIIIIIII

I,

I!!

I,II

FIGure 9.

- Cascade Reservoir topology map, No. 3-D-2879.
- - -

CASCADE RESERVOIR AREA - CAPACITY CURVES

Area (acre)

36000 32000 28000 24000 20000 16000 12000 8000 4000

4840

4830

4820

4810

0

9..

>

a,

w

4790

4780

4770

4760

0

_-_ _

CAPACITYAREA

4840

4830

4820

4810

4800

4790

4780

4770

4760

0 100000 200000 300000 400000 500000 600000 700000 800000 900000

Capacity (acre-feet)

Figure 10. - 1995 area and capacity curves.

31
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.