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Plan of Operation- Water Year 1977 For average runoff conditions during water year 1977, the projected operation of each of the reser- voirs in the Colorado River Basin is described in the following para9raphs, Charts 1 through 9 show hydrographs of the projected monthly outflow from the reservoirs and the projected end-of-month ele- vation and active storage in the reservoirs for average and three other assumptions of 1977 mod- ified runoff from the Basin. The four assumptions are: (1) AVERAGE based on the 1906-68 record of runoff, (2) UPPER QUARTILE based on flows exceeded 25 percent of the time during 1906-68, (3) LOWER QUARTILE based on flows exceeded 75 percent of the time during 1906-68, and (4) MOST ADVERSE based on the lowest year of rec- ord, which occurred in 1934, The projected releases trom Lake Powell are 8.23 miilion acre-feet for the most adverse and lower quartile assumed runoff conditions. The average and upper quartile assumed runoff conditions would cause a splitting of storage condition be- tween Lake Mead and Lake Powell, and releases from Lake Powell would be 9,2 and 10:4 million acre-feet, respectively. The average and upper quartile Lake Poweil re- lease would cause Lake Mead to rise 7 feet and 15 feet higher at the end of the current year than the level reached by the most adverse condition. The projected operations of Lake Mohave and Lake Havasu are the same under ail four of the runoff assumptions, ALTERNATIVE PLAN OF OPERATION A review is currently being made of the terms and conditions of the "Criteria for Coordinated Long- Range Operation of Colorado River Reservoirs" and their relation to the "Fiiling Criteria" (General Principles to Govern, and Operating Criteria, for Glen Canyon Reservoir and Lake Mead During the Lake Poweil Filling Period). This review in- cludes a study of the merits of alternative plans of operation associated with the release of water from Lake Mead in excess of downstream require- ments lor beneficial consumptive use. The sched- uling of additional releases would lessen the risk of future downstream flood damage and would tend to avoid the need at some future date to by- pass water in excess of powerplant capacities. Before implementing such an alternative plan for the water year 1977, the views of the seven Colo- rado River Basin States regarding the potential benefits versus risks related to such additional releases would be sought. The additionai water releases could be scheduled for use by Mexico as part of the plan, but such releases could not be regarded as a precedent for release of water in future years, It is anticipated that such. a plan might include the release of 200,000 acre-feet of water during calendar year 1977 based on the present condition of storage within the Colorado River system, If the late spring forecasts indicate an average or above average runoff for water year 1977, the views of the Colorado River Basin States will be solicited on the merits and risks of releas- ing even greater amounls of additional water. r'" _.....-.;n~. -- 'i(I .j" ~r.. ", I -, / - ':/"-~., .., ~o;r.,..~p ;~~?~~~"~:~~.~~j: . ,',.. :~. ::~7-':1~;<.:;,,,, r.,;:;, ,,' ,.'. .4':~\"Y'{'",F. .:.., . -1': ,~{:(\"ij tc'.fI;J ~~~,~ Great Blue Heron make nests at Topock Marsh. Green River immediately below Flaming Gorge 08",.