WSP00585 - Laserfiche WebLink

Home Browse Search

Projected Plan of Operation - Water Year 1987 A proposed operation plan for water year 1987 for major reservoirs of the Colorado River system was formulated and distributed to representatives of the Colorado River Basin States in November 1986. This plan was prepared in accordance with the Operating Criteria published June 4, 1970, in compliance with section 602, Public Law 90-537. The plan reflects operation for flood contro~ domestic and irrigation use of water, hydroelectric power generation, water quality control, fish and wildlife propagation, recreation, and Colorado River Compact requirements. The water year 1987 plan is essentially the same as the plan developed for water year 1986. During the rust three months of water year 1987, releases will be at 45 percent of powerplant capacity at Glen Canyon, then releases will increase during January 1987 in order to develop sufficient vacant reservoir space to reduce the risk of spilling. This also reduces the risk of damaging flood releases from Hoover, Oavis, and Parker Dams, should large runoff forecasts occur during the 1987 runoff period. Releases from January through July will be based upon the runoff forecasts received during that time but will result in greater available space on August 1, 1987, than the minimum flood control requirement of 1.5 MAF. The plan calls for a total Glen Canyon release in water year 1987 of 11.7 MAF under reasonable minimum inflow conditions. An annual release of14.7 MAFwould be required under most probable inflow conditions, which would fill Lake Powell and also equalize the active contents of Lake Powell and Lake Mead by September 30, 1987. With a reasonable maximum inflow during water year 1987, the projected Glen Canyon releases would be 17.6 MAF. This volume of inflow would require maximum powerplant releases during April through August, and 75 percent powerplant capacity during tbe remainder of water year 1987 to avoid the use of Glen Canyon's river outlet works or spillways. The projected operation for most probable runoff conditions for the major reservoirs in the Colorado River Basin for water year 1987 is described in the follnwing pages. Charts showing the projected monthly outflows from each reservoir for the three assumed hydrologic conditions are presented with each reservoir operation. Each of these assumptions uses the most current hydrologic information available by including actual forecasted October through Oecember 1986 inflows. The monthly inflows for the remainder of the year were based upon the following assumptions; (1) reasonable maximum based upon the annual volume of inflow which would be exceeded about 10 percent of the time; (2) most probable based upon the 1906 through 1983 natural flows developed for the Colorado River Simulation System (CRSS) model depleted up to current levels; and (3) reasonable minimum based upon the annual volume of inflow which would be exceeded about 90 percent of the time. 4