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<br />Flood Control <br /> <br />Lake Mead is operated in accordance with updated flood <br />control regulations which are specifIed in the Field Working <br />Agreement between Reclamation and the Corps of <br />Engineers, signed in 1982. The regulations stipulate the <br />minimum release levels needed from Lake Mead to route <br />the reasonable maximum inflow. The reasonable maximum <br />inflow is the estimated inflow volume that, on the average, <br />will not be exceeded 19 out of 20 times. This volume is <br />derived by adding an "uncertainty" term to the most probable <br />runoff forecast. In 1983, unusual hydrometeorological events <br />resulted in unprecedented large forecasting errors. <br />Subsequent reassessment of the estimate of the "uncertainty" <br />term led to adoption of larger values for use in determining <br />the reasonable maximDm inflow in 1984 and thereafter. <br /> <br />Due to the amount of vacant storage space in Colorado <br />River reservoirs, no flood control releases are anticipated in <br />1996, but in future years, as Lake Mead refUls and flood <br />control releases are again required by the Hoover Dam <br />Flood Control Regulations, consideration will be given to <br />making those releases over the fall and winter months to <br />avoid high flow rates during the subsequent January to July <br />runoff seasOD. This distribution of water reduces the chance <br />of bypassing hydroelectric powerplants below Hoover Dam <br />and avoids the adverse impacts of higher flood control <br />releases on fIsh and wildlife, recreation, water quality, and <br />river stabi1ization. <br /> <br />Routine maintenance of bankline protection facilities were <br />carried out during water year 1995. As in the previous years, <br />increasing bankJine repair was necessitated in part by wave <br />action from boating and other recreational river traffic. <br />During water year 1995, the river channel in the Lower <br />Basin has remained in good balance, neither aggrading nor <br />degrading significantly in any particular reach. The residual <br />10 million cubic yards of sediment introduced into the <br />Colorado River by the 1992-1993 Gila River flows continue <br />to create problems of river instability, high ground water and <br />difficulties with Mexico's diversion at Morelos Dam. <br /> <br />Total Colorado River reservoir system storage at the start of <br />water year 1995 was approximately 55.0 billion cubic meters <br />(44.6 million acre-feet) and about 63.3 billion cubic meters <br />(51.3 million acre-feet) at the end of the water year, <br />re.presenting an 8.3 billion cubic meters (6.7 million acre- <br />feet) decrease in total remaining available reservoir space. <br /> <br />During water year 1996, the Corps of Engineers flood <br />control facilities; Painted Rock (Gila River) and Alamo <br />Reservoirs are expected to be operated in acwrdance with <br />Reclamation project releases and established flood control <br />criteria to maximize the available flood control space in their <br />respective reservoirs. <br /> <br />22 <br />