Annual Report Operation of the Colorado River Basin 1980 Projected Operations 1981 Colorado River Basin

Wyoming

Nevada

New Mexico

In May of 1981, the Secretary of the Interior ap­ proved changing the Water and Power Resources Service back to its former name, the Bureau of Reclamation. All references in this publication to the Water and Power Resources Service should be considered synonymous with the Bureau of Reclamation. Contents U.S. Department of the Interior

Bureau of Reclamation

January 1981

(Prepared pursuant to the Colorado River Basin Project Act of1968, Public Law 90-537)

Sandstone formations tower above Lake Powell London Bridge and English Village at Lake Havasu Citrus Harvesting Introduction ...... 2 Authority for Report ...... 2 Actual Operations Under Criteria-Water Year 1980 ...... 2 Projected Plan of Operation Under Criteria-Water Year 1981 ...... 3 Determination of "602(a) Storage" ...... 3 Mexican Treaty Obligations ...... 3 Regulatory Wastes ...... 4 Additional Releases ...... 5 Projected Plan of Operation-Water Year 1981 7 Upper Basin Reservoirs Fontenelle Reservoir...... 8 Flaming Gorge Reservoir 10 Wayne N. Aspinall Unit-Blue Mesa, Morrow Point and Crystal Reservoirs 12 Navajo Reservoir ...... 14 Lake Powell ...... 16 Lower Basin Reservoirs Lake Mead 18 Lake Mohave 20 Lake Havasu 22 River Regulation ...... 24 Flood Control...... 25 Beneficial Consumptive Uses Upper Basin Uses and Losses 26 Lower Basin Uses and Losses 26 Water Quality Operations 28 Enhancement of Fish and Wildlife Upper Basin 29 Lower Basin 30 Preservation of Environment 31 Power Operations Upper Basin-Colorado River Storage Project 32 Generating Unit Maintenance 33 Lower Basin 34 Generating Unit Maintenance 3'5

1 Introduction Authority for Report Actual Operations Under Criteria-Water Year 1980

Navajo Dam and Reservoir Aerial of Fontenelle Dam Fontenelle Dam, Seedskadee Project, Wyoming

The operation of the Colorado River Pursuant to the Colorado River Basin The operational plan for water year 1980 Basin during the past year and the pro­ Project Act (Public Law 90-537) of 1968, reflected the concept of Hoover storage jected operations for the current year I am pleased to present to the Congress, credits established during 1979. Prior to reflect domestic use, irrigation, hydro­ and to the Governors of the Colorado filling of Lake Powell in June 1980, anti­ electric power generation, flood control, River Basin States, the tenth annual cipatory releases from Lake Mead for water quality control, fish and wildlife report on the Operation of the Colorado flood control and river regulation pur­ propagation, recreation, and Colorado River Basin. This report describes the poses were accounted for as if actually River Compact requirements. actual operation of the reservoirs in the stored in Lake Mead. Scheduling a mini­ Colorado River drainage area constructed mum annual release of 8.23 million Storage and release of water from the under the authority of the Colorado River acre-feet from Lake Powell during fall of Upper Basin reservoirs are governed by Storage Project Act, the Boulder Canyon 1979 and winter of 1980 was planned on all applicable laws and agreements con­ Project Act, and the Boulder Canyon the basis that, under any reasonable cerning the Colorado River, including Project Adjustment Act during water year inflow conditions, the active storage of the impoundment and release of water in 1980 and the projected operation of Lake Powell would have been less than the Upper Basin required by Sec. 602(a) these reservoirs during water year 1981 theoretical storage of Lake Mead by of Public Law 90-537. The operation of under the "Criteria for Coordinated Long­ September 30, 1980. the Lower Basin reservoirs reflects Range Operation of Colorado River Mexican Treaty obligations and Lower Reservoirs," published in the Federal As it became apparent from updated Basin contractual commitments. Register June 10, 1970. forecasts that the inflow would be suffi­ cient, the scheduled releases were Nothing in this report is intended to James G. Watt, Secretary revised with the objectives of filling Lake interpret the provisions of the Colo­ U.S. Department of the Interior Powell while releasing water on a sched­ rado River Compact (45 Stat. 1057), the ule to optimize power production. Re­ Upper Colorado River Basin Compact leases from the other reservoirs were (63 Stat. 31), the Water Treaty of 1944 made to meet the mUltiple purpose with the United Mexican States (Treaty demands of the system including flood Series 994, 59 Stat. 1219), the decree control, water supply, power production, entered by the Supreme Court of the recreation, and fish and wildlife enhance­ United States in Arizona v. California, ment. et al. (376 U.S. 340), the Boulder Canyon Project Act (45 Stat. 1057), the Boulder Canyon Project Adjustment Act 54 Stat. 774; 43 U.S.C. 618a), the Colorado River Storage Project Act (70 Stat. 105; 43 U.S.C. 620), or the Colorado River Basin Project Act (82 Stat. 885; 43 U.S.C. 1501). Projected Plan of Operation Under Criteria-WaterYear 1981

Workers at Parker Dam During water year 1980, the water supply Determination of "602(a) Storage" eries under Sec. 602(a)(1) and (2) of in the Colorado River Basin was approxi­ Sec. 602(a)(3) of the Colorado River Public Law 90-537. mately 124 percent of the long-term Basin Project Act of September 30, 1968, average, ranging from 106 percent for the (Public Law 90-537), provides for the Taking into consideration these relevant Green River at Fontenelle Dam to 132 storage of Colorado River water not re­ factors, the Secretary has determined percent for the San Juan River at Navajo quired to be released under article III(c) that the active storage in Upper Basin Dam. Aggregate Colorado River System and III(d) of the Colorado River Compact reservoirs forecast for September 30, storage at the end of the water year was in Upper Basin reservoirs to the extent 1981, exceeds the "602(a) Storage" 54,512,000 acre-feet, representing an the Secretary fi nds it necessary to assure requirement under any reasonable range increase of 3,573,000 acre-feet from the Compact deliveries without impairment of assumptions which might be realis­ previous year. of annual consumptive uses in the Upper tically applied to those items which he is Basin. Article II of the "Criteria for Coor­ directed to consider in establishing this On June 22, 1980, Lake Powell filled to dinated Long-Range Operation of Colo­ storage requirement. Therefore, the capacity, terminating the filling criteria. rado River Reservoirs" provides that the accumulation of "602(a) Storage" is not On September 30, 1980, the active con­ annual plan of operation shall include a the criterion governing the release of tent of Lake Powell was 23,084,000 acre­ determination by the Secretary of the water during the current year. feet and the theoretical storage of Lake quantity of water considered necessary to Mead was 24,223,000 acre-feet (actual be in Upper Basin storage as of Septem­ storage was 23,637,000 acre-feet). ber 30 of the current year. This deter­ Mexican Treaty Obligations Releases from Lake Powell amounted to mination shall consider all applicable Annual calendar year schedules of 10,920,000 acre-feet. By the end of the laws and relevant factors including, but monthly deliveries of water in the limi­ water year, the goals of the 1980 opera­ not limited to the following: (a) historic trophe section of the Colorado River, tion plan for the major storage reservoirs streamflows; (b) the most critical period of allotted in accordance with the Mexican in the system had been achieved. record; (c) probabilities of water supply; Water Treaty signed in 1944, are formu­ (d) estimated future depletions in the lated by the Mexican Section and pre­ A description of the operations of each Upper Basin, including the effects of sented to the United States Section, reservoir in the Colorado River Basin recurrence of critical periods of water International Boundary and Water follows. Charts 1-8 show monthly outflow, supply; (e) the "Report of the Committee Commission, before the beginning of water surface elevation, and active on Probabilities and Test Studies to the each calendar year. storage in each reservoir during water Task Force on Operating Criteria for the year 1980. Colorado River," dated October 30, 1969, and such additional studies as the Secre­ tary deems necessary; (f) the necessity to assure that Upper Basin consumptive uses are not impaired because of failure to store sufficient water to assure deliv- 3 Upon 30 days' advance notice to the Of the 4,050,000 acre-feet of mainstream Regulatory Wastes United States Section, Mexico has the Colorado River water reaching the Deliveries to Mexico consist of river right to modify, within the total schedule, boundary, about 3,059,000 was delivered water delivered to Imperial Dam and any monthly quantity prescribed by the through Pilot Knob wasteway from the waste and drainage return flows from schedule by not more than 20 percent. All-American Canal. An estimated 750,000 water users below Imperial Dam. In addi­ During water year 1980, Mexico received acre-feet delivery resulted from water tion to assuring normal water deliveries a total delivery of about 5,850,000 acre­ released through Laguna Dam and the the small amount of regulatory storage feet at the Northerly International Bound­ remainder was made up of return flows space in Imperial, Laguna, the Senator ary. Of that amount, it is estimated that to the Colorado River below Laguna Wash Reservoirs was used at times to about 1,800,000 acre-feet was attributable Dam, and returns to the Gila River below limit potential downstream flood damages to Gila River inflow and the remainder, or the gaging station near Dome, Ariz: during water year 1980. about 4,050,000 acre-feet, was released from the Colorado River mainstream The United States will make scheduled Regulatory waste for water year 1981 will reservoirs. deliveries of 1,700,000 acre-feet of Colo­ depend on the actual hydrologic condi­ rado River water to the Republic of tions occurring during that time. The Gila River inflow to the Colorado is Mexico in calendar year 1981. This in­ largely a result of flood control releases cludes an additional 200,000 acre-feet of from Painted Rock Dam. water surplus to United States uses, pur­ suant to the Mexican Water Treay of 1944.

The additional water release is based in part on average runoff conditions assumed for the Colorado River Basin during water year 1981. Should runoff during that time be above average, substantially larger releases for flood control purposes could be required from Hoover Dam and Repre­ sentatives of the Republic of Mexico will be kept informed of operating schedules through the United States Section of the Commission. Additional Releases

View of Weeping Rock, Green River Water Year 1980 The Commissioner, United States Sec­ tion. This plan of operation, including the On August 21, 1979, the Colorado River tion, International Boundary and Water further additional releases, was also Basin States and other interested parties Commission, was notified of the availability implemented consistent with the opera­ met in Salt Lake City, Utah, to discuss of additional water for Mexico during tional strategy approved by the Assistant the operational plan for the Colorado calendar year 1980 and a monthly sched­ Secretary of the Interior in 1979. The River and schedule of releases from Lake ule for delivery of up to 1,700,000 acre­ Colorado River Basin States were sub­ Mead during water year 1980. Recog­ feet pursuant to the Mexican Water sequently notified that such releases nizing the high probability of flood con­ Treaty of 1944 was requested. from Lake Mead during the period, which trol releases being required during 1980 would create storage space greater than and 1981, the plan adopted for 1980 During the winter and spring months that required by the then current flood included the release from Lake Mead of precJpitation and snow accumulation in control regulations, would be accounted about 700,000 acre-feet of water in the Upper Basin resulted in higher than for as being retained in storage for the excess of downstream requirements for average runoff to Lake Powell. Further­ purposes of storage equalization under the purposes of river regulation and more, high runoff conditions in the Bill Sec. 602(a), Public Law 90-537. anticipated flood control operation. This Williams River and Gila River drainages operating plan was also consistent with mandated winter and spring flood con­ the declaration made by the trol releases by the Corps of Engineers Representatives of the Secretary of the from Alamo and Painted Rock Dams. Interior at the integration meeting held June 13, 1979, in Boulder City, Nev., to On April 10, 1980 a meeting of Federal, release water at Hoover Dam sufficient to State, and Basin interests to discuss generate contract-defined firm energy "Colorado River Basin Water Conditions" during operating year 1980. and proposed plans for reservoir opera­ tions was held in Las Vegas, Nev. The principal subject of discussion at that meeting was the proposed release of an average of 19,000 cubic feet per second from Parker Dam beginning May 1, 1980, and continuing through December 31, 1980, in order to avoid making future releases of a flooding magnitude and, coincidentally, to optimize power genera-

5 Trout fisherman Lake Powell filled to elevation 3,700 feet During the months of April, May, and on June 22, 1980, terminating the "Filling June 1980, studies indicate that total Criteria". releases of 5,471,000 acre-feet would have been required consistent with flood con­ On September 30, 1980, the actual eleva­ trol regulations. This would have been an tion of Lake Mead was 1,204.92 feet excess of 3,105,000 acre-feet above con­ (23,637,000 acre-feet). Actual releases at sumptive use requirements for those Hoover Dam for water year 1980 totaled three months. Releases for the entire 9,958,000 acre-feet. This figure includes water year 1980 would have totaled 6,899,000 acre-feet for minimum down­ 10,004,000 acre-feet, an excess of 46,000 stream consumptive use, and 3,059,000 above what was actually released during acre-feet scheduled to create additional water year 1980. flood control space in the reservoir. Anticipatory release of water from Lake If none of this additional water had been Mead was initiated in May 1979. If no released from Lake Mead during water anticipatory releases had been made year 1980, the reservoir's flood control during 1979 or 1980, Lake Mead's eleva­ regulations would have forced mandatory tion would have been approximately release levels beginning in April 1980. 1,208.85 feet (24,223,000 acre-feet) on September 30, 1980.

6 Projected Plan of Operation­ Water Year 1981

Water Year 1981 The plan of operation for the Colorado For average runoff conditions during At the meeting in Las Vegas, Nevada, on River system that was implemented on water year 1981, the projected operation December 11, 1980, representatives of the October 1, 1980, and was presented at of each of the reservoirs in the Colorado seven basin states were advised that the the meeting in Las Vegas on December 11 , River Basin are described in the following active storage in Upper Basin Reservoirs 1980, was based on the amount of storage pages. Charts 1-8 show the projected on September 30, 1980, exceeded by in the system at the beginning of water monthly outflows from the reservoirs and more than 10 million acre-feet the require­ year 1981. The plan includes releases the projected end-of-month elevation and ment for "602(a) Storage" as provided from Lake Powell and Lake Mead being active storage in the reservoirs for average in the Colorado River Basin Project Act made in order to avoid anticipated flood­ assumed runoff conditions and three other of 1968, and that the Lake Mead storage ing and spills to the extent consistent assumptions of modified runoffs from the credits that had accumulated to date with maximum water conservation. Basin for 1981. The four assumptions would be extinguished and no further are (1) Average based on the 1906-79 credits would be accumulated during Lake Powell is being operated to avoid record runoff; (2) Upper quartile based water year 1981 . anticipated spills and to equalize the on the annual level of annual streamflow levels of Lake Powell and Lake Mead which has been exceeded 25 percent of Attendees at the Las Vegas meeting before December 31, 1981. Based on the the time during 1906-79; (3) Lower quartile were invited to provide comments on newly instituted interim flood control based on flows exceeded 75 percent of the proposed operation plan for water agreement with the Corps of Engineers, the time during 1906-79; (4) Most adverse year 1981 by January 31, 1981. releases from Lake Mead are being based on the lowest year of record, which scheduled during the fall and winter was 1977. The projected operations of After due consideration of all comments months in anticipation of release require­ Lake Mead reflect levels of anticipatory received and upon advice from the Sol­ ments for flood control in an average releases for flood control during October icitor for Interior, the Secretary deter­ year. Based on current reservoir condi­ through February and adjustments in mined that the use of Lake Mead storage tions and updated hydrologic forecasts, actual releases for flood control during credits was not warranted after the anticipatory releases from Lake Mead January through July that would result filling of Lake Powell on June 22, 1980. each month will be adjusted either up­ with the occurrence of the four assumed Further deliberations regarding the wards or downwards as necessary to meet runoff conditions. The projected oper­ proposal to continue the use of storage the objective of having full reservoir ations of Lake Mohave and Lake Havasu credits led to the conclusion that the conditions by the time the Central Arizona also reflect the releases from Lake Mead Secretary of the Interior could not allow Project (CAP) comes on line. These objec­ resulting from system operations under the use of Lake Mead sitorage credits tives are incorporated in the year's these assumed runoff conditions. after Lake Powell had filled because operating plan and are not intended as Section 602(a)(3)(ii) of Public Law 90-537 a modification of the current "long-range requires that active storage in Lake Mead operating criteria" or to set a precedent be maintained, as nearly as practicable, as to how the system might be operated equal to Lake Powell active storage. in future years. 7 Upper Basin Reservoirs Fontenelle Reservoir (Green River)

¥ .. ~<. Fontenelle spillway Fontenelle Dam spillway

Water Year 1980 Water Year 1981 Fontenelle Active Storage* Chart 1 Fontenelle Reservoir is operated for At the beginning of year 1981, the eleva­ power generation, water supply, flood tion at Fontenelle Reservoir was 6,499 Reservoir (Acre-Feet) EI.(Ft.) control, fish and wildlife enhancement, feet with a content of 294,000 acre-feet. Maximum Storage 344,834 6506 and recreation. The water surface was Releases from the reservoir will be sched­ Rated Head 233,789 6491 gradually reduced from an elevation of uled to draw the water down to 6,480 feet Minimum Power 194,962 6485 6,499 feet at the beginning of the water prior to the spring runoff Su rface Area (FuII) 8058 Acres year to a low of 6,477 feet in April prior Reservoir Length to the spring runoff. The minimum release The reservoir will fill in July 1981 unless (Full) 18 Miles during the fall and winter was 700 cubic the inflow is less than average. After the Power Plant feet per second (ft3 IS). The maximum spring runoff, the reservoir level will be release for the water year was 6,975 ft3 Is. controlled by adjusting the releases Number of Units 1 The maxi.,mum inflow of 9,715 ft3 /s oc­ through the powerplant to reduce slowly Total Capacity 10,000 Kilowatts curred on May 25. On May 26, the reser­ the elevation to 6,504 feet by the end of *does not include 563 acre·feet of dead storage voir was filled to capacity with an eleva­ the summer of 1981. below 6408 feet tion of 6,506 feet. The minimum release for power generation is 500 feIs; the The maximum release, dependent pri­ maximum release through the powerplant marily on the magnitude of the inflow, is is 1,750 ft3 Is at rated head. also contingent on forecast error. Unless the inflow is larger than what has been historically experienced, the projected maximum release is less than 15,000 feIs. If the inflow is in the upper quartile, peak outflow is expected to be less than 10,000 ft3Is. With an average inflow, the anticipated peak outflow is less than 7,000 ft3 Is. Assuming a lower quartile inflow, the outflow will probably be no greater than 3,000 ft3 /s.

8 Another view of spillway Dam and Green River, looking upstream

Outflow Release in 1000 Cubic Feet/Second. Storage Actual Operation 1980 Usable Content in 1000 Acre-Feet Elevation (Feet) Non-linear Scale 5 4 31---+----+----I--I----f-----4-+-- 345 '~---4---+--+---l~+---+--+- 2....---+---+----4--+--+----4-- 1 300ll---+---I--+---+----I---+--~ Projected Operation 1981 Upper Quartile 7 6 200, 6486 5 4 3 2 6465 1 "'~~'~::"~~\ :>:"i;::;, ,>':;:::"" ':" ,,,,,~,;:: !:;,::,:',;:: :~:/<::, i;::/:), ::::><: >"L;i:::: :::""" :'" '''::::'''':' ;"i",,,,,:

Average

51---+---+--1----+----+--+---+---+--1----+----+----1 41---+---+--1----+----+--+---+---+--+---+----+----1 FMAM JJ A SON 0 J FMAM JJ A ""S~ ,6392 3 I--_+_--+--I---_+__--+--+---+ Projected 1981 2~-4---+--1---l----+--~ 1

Lower Quartile Legend 31---+----+--1---l----+--~-+---+--~-l----+----l Most Probable 2~-+--+-+----+--+-+---+--+~Mm~-+---I Upper Quartile 1 Lower Quartile Most Adverse •••••••••• Most Adverse 3 2~-4--+-----11----4--+--~-+--+-----11----4--+----I 1 9 Flaming Gorge Reservoir (Green River)

Canadian Geese Flaming Gorge Dam' and Reservoir

Water Year 1980 Water Year 1981 Flaming Gorge Active Storage* Chart 2 At the beginning of water year 1980, the During water year 1981 , the reservoir reservoir water surface elevation was level at Flaming Gorge will be drawn from Reservoir (Acre-Feet) EI. 6,008 feet with a content of 2,569,000 6,023 feet to about 6,018 feet before the (Ft.) acre-feet. The April through July 1980 spring of 1981. The water level should runoff above Flaming Gorge was 1,496,000 remain high enough to launch boats Maximum Storage 3,749,000 6040 acre-feet, 131 percent of the long-term from the reservoir's nine ramps. Average Rated Head 1,062,000 5946 average. With this runoff, the reservoir inflow would result in a maximum eleva­ Minimum Power 233,000 5871 reached its seasonal maximum elevation tion of 6,031 feet with a storage of Surface Area (Full) 42,020 Acres of 6,024 feet with a content of 3,124,000 3,387,000 acre-feet during July. Flow in Reservoir Length. acre-feet at the end of July. By the end the river below the dam is not expected (Full) 91 Miles of September, the elevation was 6,023 to exceed 4,600 ft3/ S or fall below 800 Power Plant feet with a content of 3,078,000 acre-feet. fe/so Number of Units 3 Total Capacity 108,000 Kilowatts The normal minimum release is 800 ft3 /s. Since there is enough storage space for a *does not include 40,000 acre-feet of dead storage The maximum release through the power­ high inflow and enough stored water in below 5740 feet plant is 4,600 ft3 /s at rated head. case of a low inflow, the release from Flaming Gorge is not dependent on inflow for water year 1981, but rather on the demand for electric power and the avail­ ability of energy for purchase and exchange.

,10 Flaming Gorge Visitors Center Flaming Gorge selective withdrawal structure

Outflow Release in 1000 Cubic Feet/Second Storage Actual Operation 1980 Usable Content in 1000 Acre-Feet Elevation in Feet (Non-Linear Scale)

31---+---+--+---+---+--~-+----+--+----+---+-----! 2 I--_+_--+ 1 3000l----+---+---+---+---+---+---+--_+__ ······:·····6021 Projected Operation 1981 Upper Quartile 6000

31---+---+--+----+---+--~-+----+--+---+----+-----! 2000 5988 2 1----4---__+_

Average 1000 5942

2 I----+--___+_ 1 ONDJFMAMJJ A SON 0 J FMAM JJ A Actual 1980 Projected 1981

Lower Quartile

3~--+----+--+---+----l--+---+--I---+---+--+----I 2 1---4--__+_ Legend 1 Most Probable Upper Quartile Lower Quartile Most Adverse Most Adverse

3 ~-+-----I---+---+----l--+---+----ll---+---+--+----I 2 1

o N 0 J FMAM JJ AS 11 Wayne N. Aspinall Unit (Gunnison River) Blue Mesa Reservoir Morrow Point Reservoir Crystal Reservoir

Morrow Point Dam Checking fish on Gunnison

Water Year 1980 Water Year 1981 Blue Mesa Active Storage* Chart 3 The Wayne N. Aspinall Unit, formerly the Assuming average inflow for water Reservoir (Acre-Feet) EI.(Ft.) Curecanti Unit, includes Blue Mesa, year 1981, Blue Mesa Reservoir is ex­ Morrow Point, and Crystal Reservoirs. pected to reach a low of 7,467 feet with Maximum Storage 829,523 7519 Blue Mesa provides nearly all of the long­ an active storage of approximately 413,000 Rated Head 249,395 7438 term regulation for all three powerplants. acre-feet in March. The projected max­ Minimum Power 81,070 7393 Morrow Point provides peaking power imum level is 7,517 feet with an active Surface Area (Full) 9,180 Acres and thus, has highly variable releases. storage of 809,000 acre-feet. Reservoir Length The primary function of Crystal Reservoir (Full) 24 Miles is to re-regulate the variable Morrow Morrow Point Reservoir will operate at or Power Plant Point releases. near its capacity during the current year. Number of Units 2 Crystal Reservoir will also operate nearly Total Capacity 60,000 Kilowatts *does not include 111,232 acre-feet of dead storage At the end of September 1979, Blue Mesa full except for daily fluctuations needed below 7358 feet Reservoir contained 629,240 acre-feet of in regulating the releases from Morrow Morrow Point Active Storage* active storage with a water surface eleva­ Point to meet diversion requirements Maximum Storage 117,025 tion of 7,506 feet. The April through July downstream from the Gunnison Tunnel. 7160 Rated Head 79,805 1980 inflow to Blue Mesa was 961,000 7108 Minimum Power 74,905 acre-feet, 25 percent greater than the If the inflow to Blue Mesa Reservoir is at 7100 long-term average; and the total water the upper quartile, the release is expected Surface Area (Full) 817 Acres Reservoir Length year inflow was 1,208,000 acre-feet. The to average 2,800 ft3/ S for several weeks (Full) water surface elevation of Blue Mesa was in June and July 1981. For average, lower 11 Miles only two-tenths of a foot short of max­ quartile and most adverse inflows, a Power Plant Number of Units 2 imum elevation in July 1980. No water maximum monthly release of about 1,400 Total Capacity 120,000 Kilowatts bypassed the powerplant during water fe/s is projected in July 1981. *does not include 165 acre-feet of dead storage year 1980. below 6808 feet Crystal Active Storage* The drawdown for power operations and Maximum Storage 17,573 6755 river regulation was great enough that no Rated Head 13,886 6742 further space evacuation for flood control Minimum Power 10,619 6729 was required. Surface Area (Full) 301 Acres Reservoir Length During water year 1980, all flows in the (Full) 7 Miles Gunnison River below the Gunnison Power Plant Tunnel were greater than 200 feIs, the Number of Units minimum discharge required to protect Total Capacity 28,000 Kilowatts the fishery in the river. *does not include 8,200 acre-feet of dead storage below 6670 feet Fishing on Blue Mesa Gunnison River bridge Crystal Dam and Reservoir

Outflow Blue Mesa Reservoir Storage Blue Mesa Reservoir Actual 1980 Release in 1000 Cubic Ft/Sec Usable Content in 1000 Acre-Feet Elevation in Feet (Non-Linear Scale)

2 900 t---t--+---+---+-t--+---+--+---+---+-~+---+-----I---+---+~~+---+--+---I---+--+----.--j 830 7519 800 7516 7505 Projected Operation 1981 700 Upper Quartile 600' 7492

2 500 7479 400 7465 300 ~ 7450 Average 200~ 7428

21----+---+---1f----+--+---I--+--+---+-+---+-----l 100; .. 7400

0 FMAM JJ A SON 0 J FMAM JJ A 5 >.7186 Projected 1981 Lower Quartile

2

Legend Most Adverse Most Probable Upper Quartile Lower Quartile 21----+---+---1--+--+---1--+---+--+-+---+-----1 Most Adverse

o N 0 J FMAM JJ AS 13 Navajo Reservoir (San Juan River)

Sailing on Navajo Lake Navajo Reservoir-Scene of Activity

Water Year 1980 Water Year 1981 Navajo Active Storage* Chart 4 During the first part of water year 1980 a On September 30, 1980, Navajo Reservoir minimum 300 ft3 Is was released for con­ stored 1,555,000 acre-feet of water at an Reservoi r (Acre-Feet) EI. sumptive use and maintenance of fish elevation of 6,076 feet. Assuming average (Ft.) and wildlife. inflow for water year 1981, the projected elevation before snowmelt runoff begins Maximum Storage 1,696,400 6085 The April-July 1980 inflow was 1,094,000 is 6,055 feet with a content of 1,282,000 Inactive Storage 660,500 5990 acre-feet, which is 154 percent of the acre-feet. By July 1981, the reservoir is Surface Area (Full) 15,610 Acres long-time average. This was the second expected to reach an elevation of 6,078 Reservoir Length consecutive year of high runoff. Conse­ feet with a content of 1,591,000 acre-feet. (Full) 33 Miles quently, Navajo Reservoir was operated This approximate elevation will be main­ *does not include 12,600 acre-feet of dead storage for flood control. During the water year, tained throughout the summer to enhance below 5775 feet the maximum inflow of 11,065 ft3 /s was recreational use. reduced to a release of 3,000 ft3 Is and no flood damage occurred. The release from Navajo Reservoir for an upper quartile inflow is projected to be In anticipation of the high runoff, the about 1,700 ft3 Is for winter through reservoir was gradually drawn down to summer 1981. For an average inflow, the 6,031 feet. Yet, by the end of the spring release is expected to be 1,700 ft3 I s for and summer runoff the reservoir filled to winter and spring, then decrease to 800 near capacity with a water level of 6,083 ft3 Is for the summer. The projected lower feet in July 1980. quartile releases are 1,500 ft3 I s for winter, 1,200 ft3 Is for spring, and 700 ft3 Is for summer. Assuming most adverse condi­ tions, the anticipated releases are 1,200 feIs for winter, and 520 ft3 Is for spring and summer.

14 Navajo Dam and Reservoir Electro-fishing on Navajo

Outflow Release in 1000 Cubic Feet/Second Storage Actual Operation 1980 Usable Content in 1000 Acre-Feet Elevation in Feet (Non-Linear Scale) 5 41---+--+-+---+--+-+---+--+-+---+---+---1 3 2 I----+----+--+--_+_- 6085 1 .~JamlliU 6072 Projected Operation 1981 Upper Quartile

41----+----+--+---+----+--+---+----+--+---+----+----1 3~-+----+--+---+----+--+---+----+--+---+----+----I 6029 2 I----+-_+__--+ 1

Average 5966

41---+--+-+---+---+-+---+---+-+---+---+---1 3~-+----+--+---+----+--+---+----+--+---+---+---I 2~-+----+--+---+---+-+---+----+--+---+---+---f 5720 1 ~ ONDJFMAMJJ A S' 0 N D J FMAM JJ A Actual 1980 Projected 1981

Lower Quartile Legend

31----+----+--+---+---+-+---+---+-+--+---+---f Most Probable 2f---+---+-+----+---+-+----+---+--+----+---+----l Upper Quartile 1 Lower Quartile Most Adverse •• ••••••• ••

Most Adverse

31----I-----+..-+---+---+-+---+---+-+---+---+---f 21----I-----+..-+---+---+-+---+----+--+--+---+---f

1 l;m:j;i;i~;~ i!~~;~i~~~~~~i, :i~~~~~~~~~~~!: ~E;afi(; :;,~~%;~~~: ~~;;N£(( :@(W((~; :(t:(1(1(1((' H:pm:~:::: ;~::::::i.::::l::·: ::::.:::::.:::~::::::.:: ::.: :l::::::::::t~:: ONDJFMAMJJ AS 15 Lake Powell (Colorado River)

Glen Canyon Spillway operating. Lees Ferry

Water Year 1980 Water Year 1981 Lake Powell Active Storage* Chart 5 During water year 1980, Lake Powell, By the end of September 1980, the eleva­ Reservoi r (Acre-Feet) EI. which is impounded by Glen Canyon tion of Lake Powell was 3,688 feet. It is (Ft.) Dam, was operated as part of the Colo­ expected to be drawn down to about rado River Storage Project in accordance 3,676 feet by spring of 1981. With an Maximum Storage 25,002,000 3700 with governing contracts and laws to pro­ average April-July inflow of approximately Rated Head 9,428,000 3570 vide river regulation, optimum power pro­ 8,000,000 acre-feet, a maximum elevation Minimum Power 4,126,000 3490 duction, recreation, and fish and wildlife of 3,696 feet is expected. At this eleva­ Surface Area (Full) 161,390 Acres enhancement. tion, the content is 24.3 million acre-feet, Reservoir Length 97 percent of active capacity, and the (Full) 186 Miles On September 30, 1979, Lake Powell surface area is approximately 158,000 Power Plant water surface elevation was 3,678 feet acres. Scheduled releases from Lake with a live storage of 21,636,000 acre­ Powell under average conditions amount Number of Units 8 feet. The April-july 1980 runoff at Lees to 9,950,000 acre-feet, 1,720,000 acre-feet Total Capacity 900,000 Kilowatts Ferry, Ariz., was 10,958,000 acre-feet, more than the minimum required by the *does not include 1,998,000 acre·feet of dead 144 percent of the long-time average. operating criteria. Equalization of storage storage below 3370 feet With this inflow, the reservoir filled to is anticipated during September 1981. If capacity for the first time. On June 22, the inflow to Lake Powell is at the lower 1980, Lake Powell exceeded elevation quartile or less, the release will be 3,700 feet and Lake Mead was at eleva­ 8,230,000 acre-feet. With an upper quar­ tion 1,201, thus terminating Lake Powell tile inflow, the release is projected to be filling criteria. Several days prior to the 11,031,000 acre-feet. filling of Lake Powell, both left and right spillways were successfully tested with flows up to 30,000 ft3/ S .

16 ~', , .~ Glen Canyon generator Interesting cliff formations below dam

Inflow - Outflow Storage Actual 1980 in 1000 Cubic Feet Second Usable content in Million Acre-Feet Elevation in Feet (Non-Linear Scale)

50 t--+--+---+----1f--+__-+---+-.."e::-,~+___+___+____f 40 t--+--+-__+-+---+--+----f.-I--+--~__+-+_____I 30 ...---+---f--+--+---+---+---IL....-+--~-+--+----1 20 ...---+--+---+-+---+---+-~- 1°._liiiiiil Projected 1981 Upper Quartile 50 __.....---.-- -~-.-- ___..-.....--_____r-....___ 40 ~-f--_+____+_-+__-f----+-~~IEJ--~__+-+___1 30 .....---+--I---I--+----+---+---I-#--+---f-l'.--+-+__--I 20 f---+--+--+-----1-..-~~--+---1~ 10 ..

Average

40 ...----+--1---1--+----+---+---1--+---+---+-+----1 30 f---f---+-__+-+--+--+-___+_---:l~~--+-__+----I 20 ...----+--I---I--+__-+----+---...IfC---+---+-~-+__-1 10

Lower Quartile 30 t---f--+---+-f---+---+---+-~+---+-__+----f 20 I---J--+---+-I--+---+---I:.~f---Pilr---+-__+----f 10

Most Adverse Legend Most Probable Upper Quartile Lower Quartile o N0JFMAMJJAS Most Adverse •••••••• · •

17 Lower Basin Reservoirs Lake Mead (Colorado River)

Hoover Dam Lake Mead Recreation

Water Year 1980 Water Year 1981 Lake Mead Active Storage* Chart 6 At the beginning of water year 1980, Lake During the 1981 water year, the Lake Reservoir (Acre-Feet) EI. Mead, impounded by Hoover Dam, had Mead water level is scheduled to rise to (Ft.) a water surface elevation of 1,195 feet elevation 1,207 feet at the end of Febru­ and an active storage of 22,242,000 acre­ ary 1981, then be drawn down to a low Maximum Storage 27,377,000 1229 feet. During the water year, releases were elevation of 1,197 feet at the end of June Rated Head 13,653,000 1123 made to meet downstream water use 1981. At that level the lake will have an Minimum Power 10,024,000 1083 requirements in the United States and average active storage of about 22.4 Surface Area (Full) 162,700 Acres Mexico, programmed levels of Lakes million acre-feet. During water year 1981 Reservoir Length Mohave and Havasu, and transit losses a total of 10 million acre-feet is scheduled (Full) 115 Miles which include river and reservoir evapo­ to be released from Lake Mead. This Power Plant ration, uses by ph reatophytes, changes release will exceed downstream require­ in bank storage, unmeasured inflows, and ments while at the same time meet com­ Number of Units 17 diversions. (As mentioned earlier in this pact requirements and existing operating Total Capacity 1,344,800 Kilowatts report, additional anticipatory releases criteria. All releases are scheduled to *does not include 2,378,000 acre-feet of dead totaling 3,059,000 acre-feet were made pass through the turbines for electric storage below 895 feet from Hoover Dam and downstream reser­ power production. voirs during water year 1980 in order to decrease the magnitude of flood control With an upper quartile inflow to the sys­ releases during 1981 and 1982). The total tem's reservoirs, it is anticipated that release from Lake Mead through Hoover instantaneous peak discharges from Dam during water year 1980 was an esti­ Hoover, Davis, and Parker Dams would mated 9,958,000 acre-feet. At the end of not be greater than normal year peaks; the water year, Lake Mead had a water however, sustained discharges may pose surface elevation of 1,205 feet and an minor problems in the United States por­ active storage of 23,637,000 acre-feet, tion of the Lower Basin and more signifi­ which reflect an increase in storage cant problems within the Republic of during the water year of 1,395,000 Mexico. acre-feet.

On September 30, 1980, the active stor­ age of Lake Mead was 553,000 acre-feet more than the active storage of Lake Powell.

18 Glen Canyon Landfill Access Road paving operation.

Outflow Release in 1000 Cubic Feet/Second Storage Actual Operation 1980 Active Content in Million Acre-Feet Elevation in Feet (Non-Linear Scale)

15~-+---I-----l~-+---+­ 1O~-+---I-----l~-+-- 25 5 ~-+--+--+--+--+----+--+--+--+----4-~+---+---+---+--;---+--+--+---+--+----i-+----+1214

Projected Operation 1981 Upper Quartile 20 1179 15. 10':. 5> 15 1136 Average, Lower Quartile, Most Adverse

10 1083

o N 0 J FMAM JJ AS 5 1012

895 ONDJFMAMJJ ASONDJ FMAMJJ A Actual 1980 Projected 1981

Legend Most Probable Upper Quartile

19 Lake Mohave (Colorado River)

Davis Dam spillway gates

Water Year 1980 Water Year 1981 Lake Mohave Active Storage* Chart 7 At the beginning of water year 1980, the The water level of Lake Mohave is sched­ water surface elevation of Lake Mohave, uled to rise through the fall and winter Reservoir (Acre-Feet) EI. which is impounded by Davis Dam, was months and reach elevation 645 feet by (Ft.) 633 feet, with an active storage of the end of May 1981. Because of heavy Maximum Storage 1,810,000 647.0 1,428,000 acre-feet. irrigation use during the summer months, Rated Head 1,188,000 623.0 the water level in Lake Mohave is ex­ Minimum Power 217,500 570.0 During the winter months, the water level pected to be drawn down to elevation Surface Area (Full) 28,200 Acres was raised to 645 feet, with an active 630 feet by the end of water year 1981. Reservoir Length storage of 1,762,000 acre-feet at the end During that time a total of 10.2 million (Full) 67 Miles of May 1980. The water level was drawn acre-feet is scheduled to be released Power Plant down during the summer and fall months from Lake Mohave to meet all down­ to its lowest elevation of the year, 633 stream requirements and this amount in­ Number of Units 5 feet. The reservoir ended the water year cludes the additional releases from Total Capacity 240,000 Kilowatts at elevation 633 feet with 1,445,000 acre­ Hoover Dam. All releases are scheduled *does not include 8,530 acre-feet of dead storage feet in active storage. for electric power production. below 533.39 feet

Lake Mohave releases were made to With an upper quartile inflow to the sys­ satisfy downstream requirements, with a tem's reservoirs, it is anticipated that small amount of re-regulation at Lake instantaneous peak discharges from Havasu. The additional releases from Hoover, Davis, and Parker Dams would Hoover Dam were also routed through not be greater than normal year peaks; Lake Mohave. During the water year however, sustained discharges may pose approximately 10,246,000 acre-feet were minor problems in the United States released at Davis Dam, all of which portion of the Lower Basin and more sig­ passed through the turbines for power nificant problems within the Republic of production. Mexico.

20 Colorado River below Davis Dam and Lake Mohave Harvesting lemons

Lake Mohave Outflow Lake Mohave Storage Actual Operation 1980 Usable Content in Million Acre-Feet Elevation in Feet (Non-Linear Scale)

1.8 I---+---+-...--+---+---+-+---+--+---+-+---+--+-----f-+--+---+--I--- 15 101---1---.+---1--1--- 5 1.5 Projected Operation 1981 Upper Quartile 1.0 15 10 5

Average~ Lower Quartile, 0.5 Most Adverse ~~ ONDJ FMAMJJA.S

21 Lake Havasu (Colorado River)

Core sample from Spillway 3, Parker Dam

Water Year 1980 used for this purpose since Alamo Reser­ Lake Havasu Active Storage* Chart 8 At the beginning of water year 1980, the voir on the Bill Williams River has been EI.(Ft.) water level of Lake Havasu, impounded in operation. Reservoi r (Acre-Feet) by Parker Dam, was at elevation 447 feet Maximum Storage 619,400 450.0 with an active storage of about 565,000 Water Year 1981 Rated Head 619,400 450.0 acre-feet. The reservoir was drawn down Lake Havasu is scheduled at the highest Minimum Power 439,400 440.0 to approximately elevation 443 feet with levels consistent with the requirements Surface Area (Full) 20,400 Acres an active storage of about 498,000 acre­ for maintaining flood control space. The Reservoir Length feet in February, to provide flood control yearly low elevation of approximately 446 (Full) 35 Miles space for runoff from the drainage area feet is scheduled for the October through Power Plant between Davis and Parker Dams. The March high flood hazard period. However, water level was then raised to approxi­ a repeat of hydrologic conditions similar Number of Units 4 mately elevation 448 feet by mid-May. to those that occurred in water year 1980 Total Capacity 120,000 Kilowatts From mid-May through July, the reservoir could require a lower elevation to provide *does not include 28,600 acre-feet of dead storage water level was maintained between 449 for river regulations and flood control below 400.0 feet and 447, with an active storage of about space for runoff from the drainage area 566,000 acre-feet at the end of July. By between Parker and Davis Dams. The the end of the water year Lake Havasu yearly high of 450 feet is scheduled for was drawn down to about 447 feet with the low flood hazard month of June. an active storage of 554,000 acre-feet. During water year 1981, a total of 9 million acre-feet is scheduled to be released During the water year, approximately from Lake Havasu to meet all downstream 9,413,000 acre-feet were released at requirements, including the additional Parker Dam, all of which passed through releases. All releases are scheduled for the turbines for power production. That electric power production. amount included the additional releases from Lake Mead during the year and the With an upper quartile inflow to the sys­ flood control releases from Alamo Dam tem's reservoirs, it is anticipated that on the Bill Williams River. instantaneous peak discharges from Hoover, Davis, and Parker Dams would Space in the top 10 feet of Lake Havasu not be greater than normal year peaks; (about 180,000 acre-feet) is reserved by however, sustained discharges may pose the United States for control of floods minor problems in the United States por­ and other uses, including river regulation. tion of the Lower Basin and more signifi­ Normally, only about the top 4 feet, or cant problems within the Republic of 77,000 acre-feet of space, have been Mexico. Citrus groves Lake Havasu

Outflow Release 1000 Cubic Feet/Second Storage Actual Operation 1980 Usable Content in 1000 Acre-Feet Elevation in Feet (Non-Linear Scale) 450 ----t----t 449

500 444 Projected Operation 1981 Upper Quartile 400 438

15""--+---1-- 10 300 , 431 5 200 ~ , ': 424

100 ',415 """"",.""", 400 "" ONDJFMAMJJ ASONDJ FMAMJJ A ""5"" Actual 1980 Projected 1981 o ND J FMAM JJ AS

23 River Regulation

West Canal Outlet Works, Fontenelle Grand Canyon

The natural virgin runoff reaching the The projected release from Lake Powell to assist in controlling water quality. Mini­ streams of the Colorado River drainage based on the most probable forecast of mum releases from Lake Powell were system above Glen Canyon Dam during runoff is 9,950,000 acre-feet. Releases 1,000 cubic feet per second (ft3 /s) during water year 1980 was estimated at about could vary from a minimum of 8,230,000 the winter months and were increased to 17.5 million acre-feet. Of this amount, acre-feet with most adverse and lower 3,000 ft3 /s during the summer months. about 4 million acre-feet of water was quartile runoff to 11,031,000 acre-feet consumptively used within the Upper with upper quartile runoff. When added Anticipatory releases and river regulation Colorado River Basin States. to the flow of the Paria River, this would below Hoover Dam were accomplished in result in an Upper Basin delivery ranging a manner which resulted in a total deliv­ Adjustments in storage in other mainstem from 89.6 to 92 million acre-feet for the ery to Mexico of approximately 4,436,000 reservoirs resulted in an inflow to Lake 1O-year period ending September 30, 1981. acre-feet in excess of the Treaty quantity Powell of 13.2 million acre-feet. The during water year 1980. Of that amount release from Glen Canyon Dam, based Normally, daily releases are made from 185,021 acre-feet of drainage waters were on measurements at the gaging station at the storage reservoirs in the Lower Basin bypassed for salinity control pursuant to Lees Ferry, Ariz., was 10,920,000 acre­ to meet the incoming orders of the water provisions of Minute No. 242 of the Inter­ feet. For the 1-year and 10-year periods user agencies. All water passes through national Boundary Water Commission. ending September 30,1980,10,967,000 the powerplant units. The daily releases acre-feet and 89,989,000 acre-feet, are regulated on an hourly basis to meet respectively, passed the compact point, -a~ as nearly as possible the power loads of Lees Ferry. - the electric power customers.- Minimum daily flows are provided in the river to maintain fishery habitat. Adjustments to the normal releases are made when con­ ditions permit to provide more satisfactory conditions for water oriented recreation activities, to provide transport for river­ borne sediment to desilting facilities, and

24 Flood Control

Alamo Dam and Lake Waterfall on Lake Fork River

Lake Mead is the only reservoir on the Extensive flood control protection was Colorado River in which a specified space provided by the reservoirs within the is exclusively allocated for mainstream Basin during water year 1980. Several flood control. Flood control regulations storm systems swept across the water­ for Hoover Dam are being updated and shed and saturated wide areas with revised by the Water and Power Re­ damaging rains. Total Colorado River sources Service and the Army Corps of reservoir system storage at the start of Engineers with the consultation and water year 1980 was approximately 50.9 advice of State and local interests. million acre-feet and about 54.5 million acre-feet at the end of the water year, A draft report has been prepared and is representing a 3.6 million acre-feet de­ in the review process. After the review crease in total remaining available reser­ process has been completed, a final voir space. report and revised regulations will be published. In addition to the mainstream structures, Alamo Dam on the Bill Williams River, An interim agreement on flood control and Painted Rock Dam on the Gila River regulations prior to publication of the (both in the Lower, Basin) received revised regulations is now in effect which unusually large amounts of flood inflow takes into account the available effective during the winter months. Painted Rock space in CRSP reservoirs as well as in and Alamo Reservoirs are scheduled to Lake Mead. be operated at minimum flood control levels during 1981.

Flood control storage space will be main­ tained in Lake Mead as stipulated in the new interim agreement between the Water and Power Resources Service and the U.S. Army Corps of Engineers.

25 Beneficial Consumptive Uses

Checking irrigation water Citrus Grove

Upper Basin Uses and Losses Lower Basin Uses and Losses During water year 1980, releases of The three largest sources of consumptive During water year 1980, an estimated approximately 10,246,000 acre-feet were use in the Upper Colorado Basin are 9,413,000 acre-feet of water were released made from Lake Mohave to provide for agricultural use within the drainage basin, from Lake Havasu to meet the require­ releases at Parker Dam; to supply diver­ diversion to adjacent drainage systems, ments for water deliveries at Imperial sion requirements of the MWD, miscella­ and evaporation losses. During water Dam, as well as those of the Colorado neous contractors, and other users; to year 1980, the estimated use for agricul­ River Indian Reservation near Parker, offset evaporation and other transit losses ture and municipal and industrial supply Ariz., the Palo Verde Irrigation District between Davis and Parker Dams; and to in the Upper Basin was 2,299,000 acre­ near Blythe, Calif., other miscellaneous maintain the scheduled levels of Lake feet. Estimated evaporation losses were users along the river, the anticipatory re­ Havasu. 700,000 acre-feet from mainstem reser­ leases and transit losses between Parker voirs plus 160,000 acre-feet from other Dam and Imperial Dam. During water year 1980, releases of ap­ reservoirs and stockponds. Approximately proximately 9,958,000 acre-feet were 640,000 acre-feet were diverted for use The major water diversion above Parker made from Lake Mead at Hoover Dam to in adjacent drainage basins. Thus, total Dam was by The Metropolitan Water Dis­ regulate the levels of Lake Mohave and estimated consumptive use amounted to trict (MWD) of Southern California. MWD to provide for the small uses and the 3,790,000 acre-feet. pumped 818,000 acre-feet from Lake losses from this reservoir. In addition, Havasu during water year 1980, which 123,000 acre-feet were diverted from Lake About 2.4 million acre-feet of water were included 3,500 acre-feet for delivery to Mead for use by Lake Mead National added to storage in Upper Basin main­ the City of Tijuana pursuant to a contract Recreation area, Boulder City, Basic stem reservoirs during 1980. This water for tern porary emergency delivery of a Management, Inc., and contractors of the will be released to the Lower Basin in portion of Mexico's Treaty entitlement. Division of Colorado River Resources, future years as required by the Colorado State of Nevada. During water year 1980 River Project Act and the laws, compacts, the total releases and diversions from and treaties upon which the operating Lake Mead were an estimated 10,081,000 criteria were promulgated pursuant to acre-feet. This amount included the antici­ Sec. 602(a) of the Act. patory releases discussed elsewhere in this report.

26 Municipal pool Cattle Feedlot-Imperial Valley

For water year 1981, a release of 9 million Consumptive uses by small users, river acre-feet from Lake Havasu has been pro­ losses or gains, and reservoir losses be­ jected, including consumptive use re­ tween Davis Dam and Parker Dam are quirements in the United States below projected to be a net loss of 306,000 Parker Dam, transit losses in the river acre-feet. between Parker Dam and the Mexican Border, Treaty deliveries to Mexico and There are no major users between Hoover the additional releases from Hoover Dam. Dam and Davis Dam. During water year 1981, consumptive uses by small users, During water year 1981, The Metropolitan river losses or gains, and reservoir losses Water District of Southern California is between Hoover Dam and Davis Dam are expected to divert 868,000 acre-feet by projected to be a net gain of 127,000 pumping from Lake Havasu. acre-feet. The net diversions from Lake Mead are projected at 84,000 acre-feet. Evaporation from Lake Mead is expected to be about 950,000 acre-feet and net gain between Glen Canyon Dam and Lake Mead is expected to be about 883,000 acre-feet.

27 Water Quality Operations

Water Quality study at Deer Creek Reservoir

Since water quality aspects of Colo­ Under the provisions of Minute No. 242, In recognizing the need to manage water rado River operations are extensively the Republic of Mexico is entitled to quality of the Colorado River, it has been described in the biennial series of receive at Morelos Dam water of a quality recommended that long term salinity reports entitled "Quality of Water, no worse than 115 parts per million (p/m) increases in the river be controlled Colorado River Basin," only minimal (± 30 p/m) greater than that arriving at through a water quality improvement pro­ discussion of this aspect of operation is Imperial Dam. However, due to the addi­ gram generally described in the Water presented in this report. Report NO.10 tional releases from Hoover, Davis, and and Power Resources Service report, of the biennial series is scheduled to Parker Dams and the flood control re­ "Colorado River Water Quality Improve­ be issued in January 1981. leases from Alamo Dam on the Bill ment Program," dated February 1972, Williams River and from Painted Rock and a status report of the same title dated During water year 1980, the United States Dam on the Gila River, the quality of January 1974. bypassed a total of 185,021 acre-feet water delivered above Morelos Dam through the Bypass Drain. This bypass during water year 1980 was better than The program calls for a Basin-wide ap­ water was replaced with a like amount of that which occurred at Imperial Dam. proach to salinity control while the Upper other water, pursuant to Minute No. 242 Basin continues to develop its compact of the International Boundary and Due to the large amount of Colorado apportioned waters. The initial step Water Commission. River infiltration to the Wellton-Mohawk towards improvement of the quality of the Irrigation and Drainage District, it is ex­ river's water was authorization by the pected that all drainage wells will be Congress (Public Law 93-320) of the pumping at a maximum rate. As a result, Colorado River Basin Salinity Control the total flows in the Bypass Drain during Project, June 24, 1974. water year 1981 are estimated to be 180,000 acre-feet. No bypass waters are expected to be returned to the Colorado River below Morelos Dam during water year 1981.

28 Enhancement of Fish and Wildlife

Avocet

Upper Basin During water year 1980, studies were Cooperative efforts between the Fish and To enhance fish habitat, the interim oper­ initiated to determine the impact of sched­ Wildlife Service and Water and Power ating rules for Fontenelle Reservoir pro­ uling releases to meet power peaking Resources Service to identify suitable vide a continuous flow of at least 300 ft3 /s demands should additional generating habitat for the endangered Colorado in the channel immediately below Fon­ capacity be made available at Glen River squawfish and humpback chub are tenelle Dam. During water year 1980, Canyon and Flaming Gorge Dams. These continuing. Results of these studies, releases for power production and other studies involved evaluating fish habitat along with recommended flows to main­ purposes maintained flows of at least and using computer modeling techniques tain habitat to conserve these endangered 400 ft3 /s. to predict available fishery habitat under fish species in the Upper Colorado River various flow regimes. Similarly, studies System, are expected in 1981. The coordinated operation of Taylor Park were undertaken on the San Juan River Reservoir and the Wayne N. Aspinall Unit below Navajo Dam to accumulate com­ On February 27, 1980, an agreement was in delivering irrigation water to the prehensive biological data necessary to signed defining the course of action to Uncompahgre Project provided fishery assess the impact of various flow regimes be taken by the Water and Power Re­ and recreational opportunities. A mini­ in the event that a powerplant is con­ sources Service, the State of Utah, Utah mum wi nter 1979-1980 release of 51 fe/ s structed at Navajo Dam. Water Conservancy District, and other from Taylor Park assured a suitable fish conservation agencies to mitigate adverse habitat in the reach between Taylor Park A 3-year study conducted by the Wyoming effects created by the Strawberry Aq ue­ and Blue Mesa Reservoirs. Throughout Department of Game and Fish and funded duct and Collection System on fisheries the year, the flow below Gunnison Tunnel under Sec. 8 of the Colorado River on the tributaries of the Duchesne River. was at least 200 feIs, the minimum Storage Act was completed. The study, The agreement provides for a minimum necessary to maintain good fish habitat undertaken to identify measures to im­ annual streamflow of 44,400 acre-feet, a in the Gunnison River below Crystal Dam. prove trout productivity in the Green significant increase from the 6,500 acre­ Below Navajo Dam, a minimum flow of River below Fontenelle Dam, confirmed feet previously mandated. According to 3 300 ft / s was maintained throughout the earlier opinions that trout production was the ag reement the Central Utah Con­ year for fish propagation. being limited primarily by lack of cover in servancy District will provide 15,800 acre­ extensive rubbly glide-flat water areas. As feet annually, while Water and Power Clear water and a minimum release of a result, a new habitat improvement pro­ Resources service, the State of Utah, and 1,000 ft3/ S created a favorable habitat for gram is being initiated under the provi­ other involved agencies will secure an species of fish introduced in the river sions of Sec. 8 in water year 1981. additional 22,100 acre-feet annually. below Glen Canyon Dam.

29 Lake Powell Artist at Lake Powell

Lower Basin Results from the Creel census by NOW has also been participating with the Cali­ During water year 1980, the Arizona and AGFD show increased harvest of the fornia Department of Fish and Game Game and Fish Department (AGFD) and striped bass. This has, in turn, favored a (CDFG), the Bureau of Land Manage­ Nevada Department of Wildlife (NOW) decrease harvest of largemouth bass ment (BLM), and Fish and Wildlife Service completed the third year of the 5-year which may help the overall largemouth (FWS), in a 1-year study on Senator Wash Lake Mead Black Bass Study. This year's fishery. Reservoir to monitor movement patterns, spawning investigations, funded by the population estimates and spawning Upper and Lower Colorado Regions of The remaining 2 years of this study will behavior of the Razorback sucker (Zyrau­ Water and Power Resources Service, emphasize the largemouth bass spawning, chen texanus). Adults of this native showed good nesting effort and success food habits, and life history. The major sucker are relatively common in the lower in the Upper Basin of Lake Mead. A total objective of the study is to identify the Colorado River (primarily Lake Mohave of 50 nests in two study coves were factors contributing to the declining har­ and Senator Wash Reservoir), but evi­ marked and monitored by AGFD biolo­ vest of largemouth bass since 1959 and dence of recruitment in recent years is gists. Combined nesting success was 58 to recommend measures for restoring the lacking. Water and Power is planning a percent in these coves and two spawning fishery to its 1959 harvest level. 2Y2-year contracted study on razorback peaks were observed in mid-March and suckers and bonytail chubs in the Black late April. Spawning effort was not as Water and Power biologists have actively Canyon area below Hoover Dam and Lake great in the NOW coves in the Lower participated in cooperative surveys of Mohave. This study will focus on the Basin of Lake Mead, but overall success native fish in the Lower Basin. Attempts status, biology, and distribution of these was good. NOW marked and monitored were made this past spring to capture native fishes in Lake Mohave. This infor­ 17 nests in two coves and showed a brood stock of the endangered bonytail mation will be used to evaluate the im­ combined nesting success of 64.7 percent. chub (Gila elegans) from Lake Mohave pacts proposed Water and Power proj­ for propagation at the Willow Beach ects such as Hoover Modification, pump Investigations also continued on types Hatchery. A total of five adults were storage or Lake Mohave re-regulation and abundance of cover, selection of taken, but all turned out to be females. might have on these fishes. cover by young-of-year bass, food habits These females are being held ·at the of fry and fingerling bass, and macroin­ Willow Beach Hatchery. Water and Power vertebrate and plankton abundance and diversity. Findings to date suggest the fluctuating lake levels have not limited bass production during the 3 years of this study.

30 Preservation of Environment

River seenie Dredge near Blythe, Calif.

Dredging to renovate Beale Slough, a Water and Power biologists will direct an to wildlife, mitigation will be developed. filled backwater area 7 miles south of intensive fishery inventory on selected The project is being planned and coordi­ Needles, California, was completed on sections of the unlined Coachella Canal nated with other State and Federal January 30, 1980. Biologists and engi­ to be completed in late October and early agencies. neers of Water and Power, CDFG, FWS, November of water year 1981. The inven­ and BLM hope to show that a suction tory will gather data on species composi­ Several deer drowned this past summer hydraulic dredge can create and enhance tion, relative abundance, standing crop, while trying to drink from the newly lined fish and wildlife values at the slough. In and age of fish in the canal. This study is reach of the Coachella Canal. Ground addition, the project provides water con­ one of the first of its kind in the south­ and aerial observations revealed several servation by removing phreatophytes. west and should contribute much to deer in the pockets of vegetation on the The project has created 33 surface acres understanding the value of canals as east flank of the Algondones Dunes. of backwaters and an island in the slough. fishery habitat. The final results of this These deer were probably traveling west study will be published in late January to water at the canal. The newly lined In addition, the dredge attempted to 1981. portion of the Coachella Canal poses a create coves of different bottom config­ problem to these deer and mitigation urations to compare the relative habitat Water and Power will conduct a selective agreements have been made between values of such configurations. Cotton­ strip clearing project in the Cibola Divi­ Water and Power, the FWS, and CDFG woods and willows will be planted on the sion of the Lower Colorado River below to alleviate the problem. Water and Power island and adjacent dredge spoil areas Palo Verde, Calif. The proposed study and YACC personnel are patrolling the over the next few years. CDFG biologists area is a 6.5-mile fringe of riparian vege­ canal nightly to cut down on deer losses. will evaluate the project's success in cre­ tation inside the flood control levees. A Five earthen ponds and 11 metal stock ating and enhancing fish and wildlife 2-year biological followup study will eval­ tanks have been placed near the canal. habitat. uate the effects of the clearing on wildlife. In addition, a windmill and watering hole Hydraulic and engineering studies indi­ have been placed on the east side of the cate that a major flood in this area could Algondones Dunes. Two more windmills overtop the levees. Selective clearing of have been planned for the near future. vegetation could decrease the chance of this happening. The study area includes an estimated 700 acres of vegetation; the proposed study would remove about 180 acres of this. Vegetation would be cleared in 50-, 75-, and 100-foot linear strips parallel to the Colorado River. If the followup study shows significant impacts

31 Power Operations

Glen Canyon Dam and Powerplant Glen Canyon generators

Upper Basin-Colorado River Water Year 1980 Revenue Storage Project (CRSP) Firm Energy Sales $42,012,565 The following table summarizes Sources of Energy Nonfirm Energy Sales the CRSP generation, purchases, disposi­ (Oil Conservation) 28,761,335 tion, and revenue from power operations Net Generation kWh Hoover Deficiencies for fiscal year 1981. Flaming Gorge 410,245,000 reimbursement 500,000 Blue Mesa 342,722,000 Parker Davis Firming The total revenue from power operations Morrow Point 447,295,000 Wheeling for others 3,358,499° in fiscal year 1980 was $75,636,637. For Fontenelle 65,624,600 Miscellaneous Income 1.'-J'-J-T.,,-,-,"-J ----'------fiscal year 1981, estimated revenues are Glen Canyon 5,113,461 ,000 Total Revenue $75,636,637 $84 million. Crystal ' 2_0_9_,3_7_1_,0_0_0 Subtotal-Net Generation 6,588,718,600 Water Year 1981 Kilowatt-hours Purchases (for) Estimated Energy Sales 6,655,000,000 Hoover Deficiencies 104,000,000 Estimated Purchases 1,938,000,000 Parker Davis Firming ° Estimated Peaking Rio Grande Firming ° Capacity Sales (kW) CRSP Firming ° Winter 80-81 243,000 Fuel Repla_c_e_m_e_n_t 55_4_,_1_0_7_,0_0_0 Summer - 81 82,000 Subtotal Purchases 658,107,000 Estimated Revenue $84,000,000 Transmission for others 224,371,131 Power Deliveries from others (I nterch_a_n--.:;g::.-e-,,-) 1_,_7_3_6,_1_8_8_,2_2_1 Total Energy Receipts 9,207,384,952

Disposition of Energy

Firm Energy Sales 5,992,745,148 Non-Firm Energy Sales 1,079,705,121 Delivery to Hoover allottees 104,000,000 Power Delivered to other (Interchange) 1,434,666,912 System Los_se_s _ 9,207,384,952 32 Refinery needs 1% millions gallons of water per day Generating Unit Maintenance GC -1 GC-2 - GC-3 '- GC-4 GC-5 - GC-6 GC-7 - GC-8 F.G. - 1 -. F.G. - 2 F.G. - 3 B.M. -1 -l- B.M. - 2 ~ ..... M.P. -1 - M.P. - 2 .- Crystal -- FonTenelle ... Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. G.C. -1 .- G.C. - 2 I--i- G.C. -3 -I- -- G.C. - 4 ~ G.C. -5 - G.C. -6 - - G.C. -7 G.C.. -8 F.G. - 1 - - F.G. - 2 F.G. - 3 B.M.-1 .~ B.M.·- 2 M.P. - 1 - ~ M.P. - 2 - ...... Crvstal Fontenelle - ~ Power Operations

Power works Hoover Powerplant Unit

Lower Basin The lower Nevada penstock at Hoover During water year 1980 the Parker Dam Water Year 1980 was out of service for a 3-week period Powerplant was modified for remote auto­ As discussed in the section on additional during water year 1980 and the lower matic control for the four 30-megawatt releases, on June 13, 1979, the Secretary Arizona penstock was out of service for units. An inspection and preventative of the Interior declared that extra water 3 weeks after the lower Nevada penstock maintenance program was carried out would be released from Hoover Dam suffi­ was again in service. Both of these meas­ during the time each of the units was out cient to generate contract-defined firm ures were for the purpose of inspection of service for the installation of the energy during the year of operation end­ and repair of the penstock linings. remote control equipment. ing May 31, 1980. The control wiring for two of the gener­ Water Year 1981 The total energy delivery to the Hoover ating units at Davis Dam was replaced for In operation studies of Lake Mead and allottees during the 1980 operating year automation in water year 1980 so that Lake Powell for the Hoover operating was 4,228,291 ,849 kilowatt-hours (kWh). these units could be controlled from year which ends May 31, 1981, the Of this total delivery, firm energy amounted the Department of Energy's Phoenix Dis­ releases at Hoover Dam have been esti­ to 3,962,080,000 kWh, deferred replace­ patch Center. This brings to a total of mated to exceed minimum downstream ment energy amounted to 100,000,000 three units which have been automated at requirements, including diversions by The kWh, and the balance was disputed and the Davis Powerplant. The remaining two Metropolitan Water District, while com­ secondary energy. Due to the June 22, units at Davis will be automated in water plying with the overall requirement to 1980, termination of filling criteria for year 1981. meet Compact and operating criteria Lake Powell, replacement energy will no release provisions. The excess water will longer be available to the Lower Basin. Phase 02 switchyard construction was generate 100 percent of the defined firm finished at Davis in water year 1980. energy. The estimated monthly Hoover All scheduled periodic maintenance at This construction consisted of new elec­ releases during the operating year total Hoover, Parker, and Davis Powerplants trical bus work and replacement of exist­ 11.2 million acre-feet. It is estimated that was performed in water year 1980. The ing power circuit breakers. Phase 02 generation from these Hoover releases, program for installation of high pressure increased the electrical capabilities at along with the Hoover to Parker-Davis thrust bearing lubrication was completed Davis to handle the future electrical load interchange, will result in delivery to the for all generating units at Hoover with the needed for the new Central Arizona allottees of about 5,232,200,000 kWh of completion of unit N5. New stainless steel pumping plants. electrical energy. runners are scheduled to be installed in Hoover units A4 and A7 in water year Deficiency power purchases have not 1981. These runners will improve the been budgeted for operating year 1981. efficiency of the unit and replace the existing worn runners. The following charts illustrate Lower Basin generator unit outage schedules 34 for water year 1980 and water year 1981. Generating Unit Maintenance Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun~ July Aug. Sep. A-1 A-1 .. A-2 A-2 - A-3 --- A-3 A-4 -- A-4 A-5 - A-5 A-6 A-6 A-7 - A-7 A-8 A-8 A-9 A-9 •• N-1 N-1 .... N-2 - N-2 N-3 - N-3 N-4 N-4 N-5 N-5 N-6 N-6 N-7 - N-7 N-8 I N-8 0-1 .. 0-1 - .- 0-2 - 0-2 0-3 •• 0-3 - 0-4 0-4 .- - 0-5 0-5 -- P-1 P-1 -- P-2 1-.. P-2 • P-3 P-3 -• • P-4 P-4 -• I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I