McKAY RESERVOIR

1993 SEDIMENTATION SURVEY

U.S. Department of the Interior

Bureau of Reclamation
7-2090 (4-81)

Bureau of Reclamation TECHNICAL REPORT STANDARD TITLE PAGE

1. REPORT NO. 3. RECIPIENT'S CATALOG NO.

4. TITLE AND SUBTITLE 5. REPORT DATE

June 1994

McKay Reservoir 6. PERFORMING ORGANIZATION CODE

1993 Sedimentation Survey

D-5753

7. AUTHOR(S) 8. PERFORMING ORGANIZATION

Ronald L. Ferrari REPORT NO.

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

Bureau of Reclamation 11. CONTRACT OR GRANT NO.

Denver Office

Denver CO 80225 13. TYPE OF REPORT AND PERIOD COVERED

12. SPONSORING AGENCY NAME AND ADDRESS

DIBR

Same

14. SPONSORING AGENCY CODE

D-5753

15. SUPPLEMENTARY NOTES

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

16. ABSTRACT

The Bureau of Reclamation surveyed the underwater area of McKay Reservoir in May 1993 to

compile field data for developing a reservoir topographic map and computing a present

storage-elevation relationship. The data were also used to calculate the volume of sediment

that has accumulated in the reservoir since dam closure in December 1927. The 1993

bathymetric survey used sonic depth recording equipment interfaced with an automated

microwave positioning system that gave continuous depth and sounding positions throughout

the reservoir. The underwater topography was developed by a computer graphics program

using the collected data. The above-water reservoir area was measured from aerial

photography obtained in October 1991. The new reservoir contour map is a combination of the

1991 aerial and 1993 underwater topography.

As of May 1993, at reservoir elevation (feet) 1322.0, the surface area was 1,283 acres, and the

total capacity was 71,534 acre-feet. Since the reservoir's initial filling in December 1927, it is

estimated that 1,909 acre-feet of sediment have been trapped in McKay Reservoir, resulting in

a 2.6-percent loss in reservoir capacity. The average annual rate of sediment accumulation

since 1927 is 29.1 acre-feet.

17. KEY WORDS AND DOCUMENT ANALYSIS

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

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

b. IDENTIFIERS- McKay Reservoir! Umatilla Projectl Columbia Basin Project Office!

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

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

(THIS REPORT) 19 UNCLASSIFIED

20. SECURITY CLASS 22. PRICE

(THIS PAGE)

UNCLASSIFIED
McKAY RESERVOIR

1993 SEDIMENTATION SURVEY

by

Ronald L. Ferrari

Sedimentation Section

Surface Water Branch

Division of Earth Sciences

Denver Office

Denver, Colorado

June 1994
ACKNOWLEDGMENTS

The Bureau of Reclamation prepared and published this report

under the supervision of Wayne Graham, Acting Head,

Sedimentation Section, Earth Sciences Division. Ronald Ferrari

of the Denver Office conducted the hydrographic survey.

Personnel from the Columbia Basin Project Office of the Pacific

Northwest Region assisted during the hydrographic survey and

performed the required land survey for the hydrographic and

aerial data collection. Special thanks to Jack McFarlin and

Doug Schmidt of the Columbia Basin Projects Office for the field

assistance during the hydrographic survey. Ronald Ferrari

completed the data processing needed to generate the• new

topographic map and area-capacity tables.

U.S. Department of the Interior

Mission Statement

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

Interior has responsibility for most of our nationally-owned public

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

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

diversity; preserving the environmental and cultural values of our

national parks and historical places; and providing for the enjoyment

of life through outdoor recreation. The Department assesses our

energy and mineral resources and works to ensure that their

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

stewardship and citizen participation in their care. The Department

also has a major responsibility for American Indian reservation

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

administration.

The information contained in this report regarding commercial

products or firms may not be used for advertising or promotional

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

product or firm by the Bureau of Reclamation.

The information contained in this report was developed for the

Bureau of Reclamation; no warranty as to the accuracy,

usefulness, or completeness is expressed or implied.

11
CONTENTS

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Page

Introduction 1

Summary and conclusions 2

Description of watershed 3

Reservoir operations 3

Survey method and equipment 3

Reservoir area and capacity 4

Original capacity 4

Development of 1993 contour areas 4

1993 revised storage capacity 4

Sediment analyses 5

References 6

Table

TABLES

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

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

2 Summary of 1993 survey results 9

Figure

FIGURES

1 McKay Reservoir location map 10

2 McKay Dam, plan and section 11

3 McKay Reservoir topographic map (map 1 of 3) 13

3 McKay Reservoir topographic map (map 2 of 3) 15

3 McKay Reservoir topographic map (map 3 of 3) 17

4 Area and capacity curves - McKay Reservoir 19

111
INTRODUCTION

McKay Dam and Reservoir, major features of the Umatila Project, are located on McKay

Creek of the Umatilla River basin. The dam, located in Umatilla County is 6 miles south of

Pendleton, Oregon (fig. 1).

On December 3, 1905, the east and west divisions of the Umatilla Project were authorized

under provisions of the original Reclamation Act, section 4, (32 Stat. 388). Recommendations

from the Board of Engineers with respect to construction of McKay Dam were approved by

the Director of the Reclamation Service on March 3, 1923. Modification of McKay Dam was

authorized by Public Law 94-228, dated March 11, 1976. McKay Reservoir is operated by the

Bureau of Reclamation. The McKay Reservoir area is a national wildlife refuge that is

heavily used by migrating waterfowl.

Construction of McKay Dam and Reservoir began in 1923 and was completed in 1927.

McKay is a homogeneous, rolled sand and gravel embankment. A continuous slab of

reinforced concrete paving on the upstream slope provides the water barrier. The

embankment was placed by spreading material in 8-inch layers and compacting with four

passes of an 11-ton traction engine. The embankment material was described as a wellgraded gravel, and the voids were filled with earth, sand, and a small percentage of clay. The

upstream concrete slab terminates at a 2.5-foot-high parapet wall at the crest and is joined

to a cutoff wall along the upstream toe of the structure. At dam crest elevation (feet) 1330.0,

McKay Dam (fig. 2) has:

• a structural height* of 165 feet

• a hydraulic height of 156 feet

• a top crest width of 23.5 feet

• a crest length of 2,700 feet

The dam has a side-channel spillway located on the right abutment. Releases are controlled

by six 20- by 10-foot radial gates and a two-barrel siphon. Releases are made into a partially

concrete lined spillway chute which conveys the flow to the outlet channel and then into

Mckay Creek below the dam. The spiiway crest design elevation was 1312.0 feet. The

spillway and chute were modified in 1978-79 to increase the discharge capacity to safely pass

the inflow design flood. The spillway capacity is 27,000 cubic feet per second at water surface

elevation 1322.0 feet.

The river outlet works, with a discharge capacity of 1,500 cubic feet per second at reservoir

elevation 1322.0, is located on the right abutment and consists of:

• rectangular intake structure with trashracks

• 10-foot diameter concrete lined horseshoe intake tunnel

• emergency gate chamber with two 4- by 4-foot hydraulically operated gates

• downstream concrete-lined horseshoe tunnel, 14 feet in diameter, containing two 54-inchdiameter steel and one 12-inch-diameter steel outlet pipes

• valve house containing two 48-inch and one 10-inch balanced needle valves. The larger

valves discharge into a rock lined plunge pooi, and the small valve discharges into a

closed conduit leading to the Marion Jack Ditch

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

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

Reservoirs, or ASCE's Nomenclature for Hydraulics.
Closure of the dam and first reservoir storage began in December 1927. At elevation 1322.0,

the reservoir extends 3.5 miles up McKay Creek and has an average width of 0.6 mile.

The 1993 reservoir survey measured a total storage capacity of 71,534 acre-feet and a surface

area of 1,909 acres at reservoir elevation 1322.0.

SUMMARY AND CONCLUSIONS

This report presents the 1993 results of the first extensive sedimentation survey of McKay

Reservoir by the Bureau of Reclamation since construction of McKay Dam. The primary

objectives of the survey were to:

• gather data needed for developing new reservoir topography

• compute area-capacity relationships

• estimate storage depletion caused by sediment deposition since closure of McKay Dam.

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

points for the aerial and hydrographic surveys. A horizontal grid system was established for

both surveys using monumented control points located in the reservoir area. The bathymetric

survey was run using sonic depth recording equipment interfaced with an automated survey

system consisting of a line-of-sight microwave positioning unit capable of determining

sounding locations within the reservoir. The system continuously recorded reservoir depth

and horizontal coordinates as the survey boat was navigated along close spaced gridlines

covering the reservoir area. The positioning system provided information to allow the boat

operator to maintain course along these gridilines. Water surface elevations measured by the

land surveyors at the time of data collection were used to convert the sonic depth

measurements to true lake bottom elevations.

The 1993 underwater surface areas at predetermined 5-foot contour intervals were generated

by a computer graphics program using the collected data. The above-water reservoir area

was measured from aerial photography obtained in October 1991. The new reservoir contour

map is a combination of the 1991 aerial and 1993 underwater topography (fig. 3). The

revised 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.

Table 1 contains a summary of reservoir watershed characteristics and sediment data for the

1993 survey. The 1993 survey determined that the reservoir has a storage capacity of 71,534

acre-feet and a surface area of 1,283 acres at reservoir elevation 1322.0. Since closure in

1927, the reservoir has accumulated a volume of 1,909 acre-feet of sediment below reservoir

elevation 1322. This volume represents a 2.60-percent loss in total capacity and an average

annual loss of 29.1 acre-feet. For sediment calculation purposes, the difference between the

original and 1993 capacity was used, but some question exists as to the accuracy of the

original area-capacity. Because of the low sediment production in the drainage area, a future

resurvey of McKay Reservoir should not be necessary unless major sediment inflow occurs

in the future.

2
DESCRIPTION OF WATERSHED

McKay Reservoir watershed has a drainage area of 186 square miles with elevations ranging

from 1182 feet at the outlet works to 4700 feet along the southeastern divide. Below

elevation 2000, the basin has gentle rolling slopes and is predominantly used for agriculture.

The soil is a silt loam and ranges in depths from 12 to 24 inches. The basin, between

elevation 2000 and 4000, tends to be V-shaped with steep side slopes and numerous rock

outcrops. The vegetative cover in the bottom of the draws is comprised of scrub brush and

some deciduous trees. The steep side slopes are open and covered with native grass. The

basin above elevation 4000 has gentle slopes and is heavily forested with very little under

brush on the forest floor. The soils are shallow, reddish in nature, and contain a large

amount of clay compared with the lower part of the basin.

RESERVOIR OPERATIONS

The reservoir is a multiuse facility having (following values are from May 1993 area-capacity

tables):

• 7,460 acre-feet of surcharge flood storage between elevations 1322.0 and 1327.6

• 6,068 acre-feet of exclusive flood control storage between elevations 1317.1 and 1322.0

• 65,466 acre-feet of exclusive conservation storage between elevations 1182.0 and 1317.1

• 0 acre-feet of dead storage below elevation 1182.0

Records for McKay Reservoir show an average unregulated inflow of 77,720 acre-feet per

year. The estimated mean annual runoff from the basin is 7.8 inches. McKay Reservoir

operation ranged from no usable contents in September 1966 to above elevation 1322.0 in

May 1991. The inflow and end-of-month stage records in table 1 show the very extreme

annual fluctuation of the reservoir. The reservoir elevation commonly fluctuates over 100

feet annually. The table only presents the 1948 through 1993 records that were readily

available. Records are available from the U.S. Geological Survey that could be used to

calculate the 1927 through 1947 operation years.

SURVEY METHOD AND EQUIPMENT

The McKay 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 photogrammetric and bathymetric survey methods.

Standard land surveying methods were used by Columbia Basin Project Office personnel to

establish horizontal and vertical control points for both survey methods. A horizontal grid

system was established for both surveys using monumented points, with state plane

coordinates, located in the reservoir area. The vertical control for the study was based on the

Bureau of Reclamation vertical datum. The above water data were collected by aerial

photography obtained on October 20, 1991, at reservoir elevation 1246.2. The field survey

work for the bathymetric survey involved establishing a triangulation network around the

reservoir to provide horizontal and vertical control for all required grid lines and shore

stations. No previously established range lines existed on the lake and no permanent range

lines were established during this survey. Because of the size and shape of the reservoir, any

future survey would also employ the contour method; therefore, permanent range line end

markers were not necessary.

3
The hydrographic survey was run on May 19 and 20, 1993, with the reservoir at water

surface elevation 1316.98 and 1317.08, respectively. The bathymetric survey was run using

sonic depth recording equipment interfaced with an automated survey system consisting of

a line-of-sight microwave positioning unit capable of determining sounding locations within

the reservoir. This positioning system transmitted line-of-sight microwave signals to fixed

shore stations and converted the reply time to range distances, which were used by the

system data logger to compute the coordinate position of the sounding boat. The survey

system continuously recorded reservoir depth and horizontal coordinates as the survey boat

moved across close-spaced gridlines covering the reservoir area. Grid spacing of 200 feet was

selected to produce adequate data for developing contours of McKay Reservoir. The system

gave directions to the boat operator to assist in maintaining course along the close-spaced

gridlines. During each run, the depth and position data were recorded on a floppy disk for

subsequent processing by Denver Office personnel. A graph plotter was used in the field to

track the boat and ensure adequate coverage during the collection process. Water surface

elevations surveyed at the time of collection were used to convert the sonic depth

measurements to true lake bottom elevations.

RESERVOIR AREA AND CAPACITY

Original Capacity

The original total capacity of McKay Reservoir was reported as 73,800 acre-feet at reservoir

elevation 1322.0. For determining change in reservoir storage, the original storage-elevation

relationship was recomputed using 5-foot surface area values projected from an area curve

dated September 23, 1937, drawing number 30-100-2. Some questions exist as to the

accuracy of this method, but the recomputed capacity at elevation 1322.0 compared fairly well

with the original. Results of the original area and capacity computations are listed in table

1 and in columns (2) and (3) of table 2.

Development of 1993 Contour Areas

The 1993 contour surface areas for McKay Reservoir were measured from the generated

contour maps from the collected aerial and underwater coordinate data. Five-foot contour

intervals, for reservoir elevations 1250.0 through 1330.0, were created of the reservoir area

by a contractor from aerial photography obtained on October 20, 1991, at reservoir elevation

1246.2. The Denver Office measured the surface areas by digitizing the five-foot contours.

Five-foot contour intervals of the underwater reservoir data, from elevations 1190.0 through

1245.0, were created by computer graphics software program SURFACE II (Kansas

Geological Survey, 1978). A modification of this program by the Denver Office calculated the

closed contour surface areas of the generated map. The final reservoir map shown on figure

3 was prepared by the Denver Office Computer Drafting Unit of the Drafting Section. The

map has a scale of one inch equals 300 feet and a contour interval of five feet.

1993 Revised Storage Capacity

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

developed using the area-capacity computer program ACAP85 (Reclamation, 1985). Surface

areas at 5-foot contour intervals computed from the aerial and underwater survey data were

used as the control parameters for computing reservoir capacity. The program computes an

area at elevation increments of 0.01 to 1.0 foot by linear interpolation between the 5-foot

4
contour intervals. The program begins by testing the initial capacity equation over successive

intervals to ensure that the equation fits within an allowable error limit, which was set at

0.00000 1 for McKay Reservoir. This capacity equation is then used over the full range of

intervals fitting within this allowable error limit. For the first interval at which the initial

allowable error limit is exceeded, a new capacity equation (integrated from the basic area

curve over that interval) tests the fit until it also exceeds the error limit. Thus, the capacity

curve is defined by a series of curves, each fitting a certain region of data. Final area

equations are derived by differentiating the capacity equations, which are of second order

polynomial form:

y = a + a2x + a3x2

where:

y = capacity,

x = elevation above a reference base,

a = intercept, and

a2 and a3 = coefficients

Results of the 1993 McKay Reservoir area and capacity computations are listed in table 1 and

columns (4) and (5) of table 2. Listed in columns (2) and (3) of table 2 are the original surface

areas and recomputed capacity values. A separate set of 1993 area and capacity tables has

been published for the 0.01-, 0.1-, and 1-foot elevation increments (Reclamation, 1993). A

description of the computations and coefficients output from the ACAP85 program is included

with these tables. Both the original and 1993 area-capacity curves are plotted on figure 4.

As of May 1993, at reservoir elevation 1322.0, the surface area was 1,283 acres with a total

capacity of 71,534 acre-feet.

SEDIMENT ANALYSES

Sediments have accumulated in McKay Reservoir to a total volume of 1,909 acre-feet since

dam closure in December 1927. The total sediment accumulation of 1,909 acre-feet has

deposited in the conservation pool below elevation 1317.1. The average annual rate of

sediment deposition between closure and May 1993 (65.5 years) was 29.1 acre-feet per year,

or 0.16 acre-foot per square mile from the sediment contributing drainage area. The storage

loss in terms of percent of original storage capacity was 2.60 percent. Tables 1 and 2 contain

the McKay Reservoir sediment accumulation and water storage data based on the 1993

resurvey.

The 1993 study based its sediment calculations on the difference between the original and

1993 measured reservoir capacities. This method would account for all sediment

accumulation during the 65.5 years of reservoir operation, but the calculations are only as

accurate as the original reservoir areas. For sediment calculation purposes the difference

between the original and 1993 capacity was used, but as noted, a question exists as to the

accuracy of the original area-capacity. A resurvey of McKay Reservoir should be considered

in the future if major sediment inflow events occur.

5
REFERENCES

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

York, 1962.

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

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

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

Denver, Colorado, 1985.

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

ofReclamation 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,

1987b.

Bureau of Reclamation, Denver Office, McKay Reservoir Area and Capacity Tables, Umatilla

Project, Pacific Northwest Region, Denver, CO, May 1993.

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

6
RESERVOIR SEDIMENT

DATA SUMMARY McKay Reservoir

NAME OF RESERVOIR

1

DATA SHEET NO.

D 1. OWNER Bureau of Reclamation 2. STREAM McKay Creek 3. STATE Oregon

A 4. SEC. 34 TWP. 2N RANGE 32E 5. NEAREST P.O. pendleton 6. COUNTY Umatilla

M 7. LAT 450 36' 28 LONG 1180 47' 30 8. TOP OF DAM ELEVATION 1330.0 9. SPILLWAY CREST 1312.0k

E

10. STORAGE

ALLOCATION

11. ELEVATIO

TOP OF PCOJL

N 2. ORIGINAL

SURFACE AREA, Ac

13. ORIGINAL

CAPACITY, AF

4. GROSS STORAG

ACRE- FEET

E 15. DATE

STORAGE

S BEGAN

E

a. SURCHARGE 1327.6 7,280 81,080

H b. FLD CONTROL 1322.0 1290 6,000 73,800 12/1927

c. POWER

I ci. WATER SUPPLY 16. DATE

R

e.

NORMAL

OPERATION

f. CONSERVATION 1317.2 1200 67,800 67,800 BEGAN

g. INACTIVE 1182.0 0 0 . 0 22/1927

17. LENGTH OF RESERVOIR 3 .5 MILES AVG. WIDTH OF RELiRVOIR 0.b MILES

18. TOTAL DRAINAGE AREA 186 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 8.22 INCHES

19 . NET SEDIMENT CONTRIBUTING AREA 186 SQUARE MILES 23. MEAN ANNUAL RUNOFF 7.8 INCHES

I 20. LENGTH MILES AV. WIDTH MILES 24. MEAN ANNUAL RUNOFF 77,720 ACRE-FEET

N

21. MAX. ELEVATION 4,700 MIN. ELEVATION 1182.0 25. ANNUAL TEMP. MEAN 53°F RANGE -11°F to 108°F

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

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

R YRS. YRS. INTERVAL

V

E

12/1927 Contour(R) 1282 73,4430 0.94

Y

5/19/93 65.5 65.5 Contour(D) 5 ft 1283.0 71,534 0.92

D

A

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

A SURVEY ANNUAL

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

5/19/93 8.2 77,720 134,80O - 77,720 -

26. DATE OF 37. PERIOD CAPACITY LOSS, ACRE-FEET [

38. TOTAL SEDIMENT DEPOSITS TO DATE, AF

SURVEY I

a. TOTAL b. AV. ANN. c. /MI.2-YR.

_____________

a. TOTAL

___________________

b. AV. ANNUAL

__________________

c. /MI.2-YR.

5/19/93 1,909 29.1 0.16 1,909 29.1 0.16

26. DATE OF 39. AV. DRY 40. SED. DEP. TONS/MI.4-YR. 41. STORAGE LOSS, PCT. 42. SEDIMENT

SURVEY MT. (#/FT3) INFLOW, PPM

a. PERIOD 5. TOTAL TO a. AV. b. TOTAL TO a. b.

DATE ANNUAL DATE PER. TOT.

5/19/93 0.048 2.608

26.

DATE

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

OF

SURVEY

132.5-

112.0

112.0-

92.0

92.0-

82.0

82.0-

72.0

72.0-

62.0

62.0

52.0

- 52.0-

42.0

42.0-

32.0

32.0-

22.0

22.0-

22.0

12.0-

Crest

Crest

*10.0

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

5/93 3.6 8.5 11.2 11.9 11.4 9. 5 5.4 3.1 9.0 14.0 10.0 0.4

26.

DATE

44. REACH DESIGNATION PERCENT OF TOTAL ORIG INAL LENGTH OF RESERVOIR

SURVEY

0-10 10-

20

20-

30

30-

40

40-

50

50-

60

60-

70

70-

80

80-

90

90-

100

100-

105

105-

110

110-

115

115-

120

120-

125

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

N/A

Table 1. - Reservoir sediment data summary (page 1 of 2).
45. RANGE IN RESERVOIR OPERATION

WATER YEAR MAX. ELEV. MIN. ELEV. INFLOW, AX WATER YEAR MAX. ELEV. WIN. ELEV. INFLOW, AK

1948 1320.5 1237.S 134,800 1949 1316.9 1238.1 67,000

1950 1320.0 1238.5 93,400 1951 1318.7 1245.8 88,800

1952 1314.5 1236.1 52,400 1953 1320.4 1235.3 95,300

1954 1303.8 1225.5 45,300 1955 1311.4 1226.4 57,300

1956 1320.4 1227.3 97,300 1957 1320.6 1226.7 74,900

1958 1320.6 1224.5 112,700 1959 1319.5 1224.6 87,400

1960 1317.0 1219.0 64,900 1961 1317.4 1197.5 65,900

1962 1305.7 1190.4 56,700 1963 1313.3 1203.1 67,700

1964 1287.9 1209.2 40,200 1965 1320.9 1214.7 119,200

1966 1290.8 1192.0 20,800 1967 1307.0 1194.4 57,900

1968 1284.0 1205.0 32,900 1969 1319.7 1206.8 94,000

1970 1319.6 1249.6 82,800 1971 1316.4 1250.3 55,900

1972 1317.0 1235.5 122,300 1973 1278.5 1193.2 25,400

1974 1317.6 1194.6 124,800 1975 1317.0 1239.4 91,000

1976 1317.2 1243.1 91,000 1977 1276.4 . 1209.2 21,600

1978 1317.7 1212.3 75,300 1979 1317.4 1238.1 99,100

1980 1317.2 1238.8 77,300 1981 1317.1 1253.5 78,800

1982 1317.2 1253.8 114,200 1983 1317.2 1251.5 121,700

1984 1317.5 1252.1 128,390 1985 1318.0 1241.5 66,010

1986 1317.4 1236.8 - 1987 1318.6 1226.8 66,760

1988 1290.1 1214.2 39,270 1989 1320.9 1213.6 113,890

1990 1298.3 1232.2 41,810 1991 1320.4 1232.1 -

1992 1305.5 1220.5 - 1993 1316.6 1220.8 -

46. ELEVATION - AREA - CAPACITY DATA FOR 19 93 TOTAL PA'. Y

'

ELEV. AREA CAP. ELEV. AREA CAP. ELEV. AREA CAP.

1186.5 0 0 1190 13.2 23 1195 31.3 134

1200 63.0 370 1205 95.3 766 1210 134.7 1,341

1215 183.4 2,136 1220 254.2 3,230 1225 312.4 4,647

1230 349.3 6,301 1235 376.1 8,114 1240 399.0 10,052

1245 429.0 12,122 1246. 2 442.9 12,645 1250 466.2 14,373

1255 506.6 16,805 1260 544.5 19,432 1265 584.4 22,255

1270 624.3 25,276 1275 663.5 28,496 1280 697.0 31,897

1285 734.3 35,475 1290 779.8 39,261 1295 831.0 43,288

1300 898.2 47,611 1305 976.7 52,298 1310 1074.6 57,426

1315 1155.0 63,000 1320 1246.8 69,005 1322 (1283) 71,534

1325 1336.1 75,462 1330 1422.9 82,359

____________ _____________ _____________

47. REMARKS AND REFERENCE.k

Spiliway overflow controlled by radial gate s and siphon. Normal water s urface elevation 1322.0.

2 Bureau o f Reclamation Project Data Book of Umatilla Project, 1966 - 80.

Calculated using mean annual runoff value o f 77,720 acre- feet, (Item 24) .

Calculated unregulated monthly inflows for reservoir operation period 1948 through 1993. Missing records for

water yea rs 1986 and 1991 though 1993. Possible to calcu late additional records, 1928 - 1947, using

available USGS records .

Surface area at reservoir elevation 1322.0. Original areas projected from the 1937 area curve.

6 Capacity at elevation 1322.0. Computed by Reclamation's ACAP program us ing original surface areas. Some

question as to the accuracy of the original surface areas caused by projecting from area curve.

Total capacity loss calculated by comparing recomputed capacity (see remark #6) and 1993 capacity at reservoir

elevation 1322.0. Original areas projected from the 1937 area curve.

Average annual and tot al sediment deposits of 29.1 acre-feet and 1,909 acre-feet, respectively, divided by 73,443

acre-feet . Capacity at El. 1322.0 computed by ACAP using original surfac e area data.

End-of-month maximum a nd minimum reservoir elevations.

10 1993 total capacity computed by ACAP using 1991 and 1993 measured areas. Area in ) ) calculated by ACAP. Areas

below elevation 1246.2 measured from 5/93 hydrographic sur vey data. Area s at elevation 1 246.2 and above measured

from 10/9 1 aerial photography.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation DATE March 1994

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

Elevation

(feet)

(2)

Original

Area

(acres)

(3)

Original

Total

Capacity

(acre-feet)

(4)

1993

Area

(acres)

(5)

1993

Capacity

(acre-feet)

(6)

Measured

Sediment

Volume

(acre-feet)

(7)

Percent

Measured

Sediment

(8)

Percent

Reservoir

Depth

1330 - - 1,422.9 82,359 - - -

1327.6 - - (1,381) 78,994 - - -

1322 1,282 73,443 (1,283) 71,534 1,909 100.0 100.0

1320 1,246 70,914 1,246.8 69,005 1,909 100.0 98.6

1317.1 1,194 67,375 (1,194) 65,466 1,909 100.0 96.6

1312 1,108 61,508 (1,107) 59,607 1,901 99.6 93.0

1310 1,076 59,324 1,074.6 57,426 1,898 99.4 91.6

1300 925 49,321 898.2 47,611 1,710 89.6 84.6

1290 808 40,704 779.8 39,261 1,443 75.6 77.5

1280 704 33,169 697.0 31,897 1,272 66.6 70.5

1270 630 26,489 624.3 25,276 1,213 63.5 63.5

1260 559 20,541 544.5 19,432 1,109 58.1 56.5

1250 488 15,300 466.2 14,373 927 48.6 49.5

1240 425 10,724 399.0 10,052 672 35.2 42.4

1230 366 6,746 349.3 6,301 445 23.3 35.4

1220 284 3,461 254.2 3,230 231 12.1 28.4

1200 55 439 63.0 370 69 3.6 14.4

1190 19 102 13.2 23 79 4.1 7.4

1186.5 13 45 0 0 45 2.4 4.9

1179.5 0 0 0 0 0 0.0 0.0

(1) Elevation of reservoir water surface.

(2) Original reservoir surface area values projected from September 23, 1937, area curve.

(3) Original reservoir capacity recomputed using ACAP85 from original surface areas from column two.

(4) Reservoir surface area from 1991 aerial and 1993 hydrographic surveys. Areas in ( ) computed by ACAP85.

(5) 1993 reservoir capacity computed by ACAP85 using areas from column four.

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

(7) Measured sediment expressed in percentage of total sediment 1,909 acre-feet at spillway crest elevation 1322.0.

(8) Depth of reservoir in percentage of total depth of 142.5 feet, from spillway crest elevation 1322.0 and river channel elevation 1179.5.

Table 2. - Summary of 1993 survey results.
Figure 1. - McKay Reservoir location map.
Space intentionally left blank due to security concerns 
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Figure 4. - Area and capacity curves - McKay Reservoir.

0
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.