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<br />,OU~203 h,otJ b h-u1 Ww\J0;~') <br />/ ~}- \--\... '.l~v'-'P' <br />outlet works) and any uncontrolled releases (spills). Each of the components of inflow and <br />outflow will be accounted separately. <br /> <br />The elevation-volume relationship for each reservoir will be specified as a series of 2nd degree <br />polynomials, where each polynomial is used for a given range of elevation. These relationships <br />are written as <br /> <br />Vr""J = C, + C,X + C,X' <br /> <br />(2) <br /> <br />where X = E, - En, E, is the elevation at the end of month t and in the range of the polynomial, <br />En is the base elevation for which the polynomial applies, and C" C" and C, are user-supplied <br />coefficients, <br /> <br />The elevation-surface area relationship will be expressed as the first derivative with respect to <br />X of equation (2), <br /> <br />A, = C, + 2C,X <br /> <br />(3) <br /> <br />We note that Equations (2) and (3) express relations between elevation, area, and volume for the <br />live capacity of the reservoirs. <br /> <br />Evaporation from a reservoir will be computed as <br />_ Cp A <br />P, - T( , + A,_I) <br /> <br />(4) <br /> <br />where Cp is a user-supplied coefficient for each month in a year and each reservoir, A" and A.'I <br />are the surface area of the reservoir at the end of month t and t-1. <br /> <br />The volume of water gained or lost from bank storage will be computed as <br />B, = BcCV;" - V,) <br /> <br />(5) <br /> <br />where Be is a user-supplied bank storage coefficient. <br /> <br />The model will account for the accumulation of sediment in reservoirs, Total annual sediment <br />volumes will be assumed constant, although distributed monthly throughout the year. The <br />volume of sediment accumulating in the live capacity of the reservoir will be computed according <br />to a Type II (Flood plain-foothill) sediment distribution (Reference 2). Elevation-area-volume <br />relationships and other reservoir parameters such as live capacity, active capacity, and dead <br />storage will be modified accordingly at the end of each time step. The elevation at the top of <br />the sediment (thalweg elevation) for time step t is computed as <br />where V,.! is the volume of sediment inflow during time step t and k is a user-supplied constant <br />for each reservoir, The initial thalweg elevations are also user-supplied. For beginning <br /> <br />5 <br /> <br />DRAFr: February 17, 1994 <br />