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Hydrograph Response Shaoe A unit hydrograph is chosen for each drainage area or sub-area <br />• model to predict the runoff response. The hydrograph responses available in the SEDCAD+ <br />model are slow, medium and fazt. A slow response corresponds to a forested area or an area <br />with a number of obstructions, whereaz a fast response corresponds to an unvegeta[ed or poorly <br />protected area. Fazt and medium hydrograph responses were chosen for disturbed and <br />undisturbed areaz, respectively. <br />Drainage Basin Area The drainage areas are de[ermined by direct measurement by <br />planimetering from a 1"-200' scale map. The maximum (worst case) areas were measured. Refer <br />to SEDCAD+ computer printout contained in Addendum D, Drainage and Sediment Control <br />Information for all measured areas. <br />Time of Concentration. Tc Time of concentration is calculated by using the SCS Upland <br />Method. All hydraulic lengths, drainage heights and slopes are measured directly from a 1"-200' <br />scale map. The values calculated for time of concentration are shown on the SEDCAD+ <br />computer printouts found in Addendum D, Drainage and Sediment Control Information. <br /> <br /> <br />A:V56ATR1J.RE~ 358Re Revised -June 1993 <br />O7/OL9J fpm <br />