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<br />001 ~ ~'i'~ <br />.L ( ,. <- <br /> <br />11.6 Capacity and Storage <br /> <br />Total capacity of a reservoir is the maximum capacity of the reservoir <br />including any flood control or surcharge capacity. Live capacity is <br />defined as that part of the total capacity from which water can be <br />withdrawn by gravity. Dead storage is equal to total capacity minus <br />live capacity.. The parameters in the CRSS that deal with reservoir <br />storage deal primarily with live capacity. These parameters include <br />current contents, live capacity, active capacity, and area-capacity <br />coefficients. None of these parameters include any dead storage. <br /> <br />Active capacity is defined as the reservoir capacity normally usable for <br />storage and regulation of reservoir inflows to meet established reser- <br />voir operating requirements. Inactive capacity is equal to the dif- <br />ference between live capacity and active capacity. Inactive capacity, <br />for example, could be set equal to the volume of water at minimum power <br />pool. In this example, inactive capacity would be equal to volume of <br />water between minimum power pool and top of dead storage. <br /> <br />As sediment accumulates in the reservoirs, the dead storage volume is <br />reduced by the CRSM using the procedures described in section 11.6.2. <br /> <br />11.6.1 Area-Capacity Equations <br /> <br />The CRSM computes reservoir water surface elevations and surface <br />areas from monthly contents, using a set of polynomial equations that <br />are different for each reservoir. The equation coefficients are <br />based on reservoir area-elevation data. The coefficients are entered <br />into the model from the CRSM control file. The model computes reser- <br />voir elevation from reservoir contents by determining the root of a <br />second-degree polynomial equation, and computes surface area from <br />elevation by solving a first-degree polynomial equation. <br /> <br />The area-capacity coefficients are occasionally updated to account <br />for increases in sediment. The area-capacity equations compute the <br />live capacity in the reservoir. <br /> <br />11.6..2 Sedimentation <br /> <br />The CRSM models the effect of sedimentation in four of the Colorado <br />River system reservoirs: Flaming Gorge, Navajo, Lake Powell, and <br />Lake Mead. The model simulates the deposition of sediment in these <br />reservoirs by accumulating on a monthly basis the amounts shown <br />below. The monthly volumes shown are for the total reservoir (live <br />capacity + dead storage). <br /> <br />52 <br />