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<br />. . <br /> <br />DESCRIPTION <br />OF <br />SOIL CONSERVATION SERVICE <br />PROGRAMS WSP2 AND TR20 <br /> <br />WSP2 <br /> <br /> <br />The WSP2 (Water Surface Profile 2) computer program provides a deter- <br /> <br /> <br />mination of flow characteristics for a given set of stream and flood <br /> <br /> <br />plain conditions. More specifically, it computes water surface profiles <br /> <br /> <br />in open channels. The program also estimates head losses at restrictive <br /> <br /> <br />sections, including roadways with either a bridge opening or culverts. <br /> <br />WSP2 rates a valley at specified points, This rating provides information <br /> <br /> <br />on elevation, discharge, flow area and flooded area, which is used as <br /> <br /> <br />part of the input data in the TR20 program. Using this information, <br /> <br /> <br />TR20 computes the water surface elevation at each cross section for peak <br /> <br /> <br />discharges, hydrograph coordinates of time versus elevation at cross <br /> <br />sections and water surface versus time at structures. <br /> <br />The standard step method, with some modifications, is used to compute <br />profiles between valley sections. All profiles are computed in the <br />upstream direction. <br /> <br />After defining a starting valley section, the program starts computations <br />from a given elevation, from given slopes, or if .no starting information <br />is given, from critical depths. <br /> <br />The energy principle is used in WSP2. Energy is considered balanced <br />when the trial elevation, plus head for that elevation at the upstream <br />section, is within 0.1 feet of the energy level at the downstream section <br />plus losses. Only friction losses are considered in the WSP2 program. <br />They are found by Manning's equation (S = (QjKO)2) using Q and KO at <br />the upstream section. The rate of friction loss is Sr, and the total <br />loss is Sr times the length (L). <br />