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Basin Information and Lag Time Computation 11 <br />Project Title: <br />Catchment ID: <br />1. Catchment Hydrologic Data <br />Catchment ID = F <br />Area = 30.41 <br />Area = 0.0475 <br />Percent Imperviousness = 5.00 <br />NRCS Soil Type = D <br />II. Analysis of Flow Time (Time of Concentration Tc) for a Catchment <br />Using SCS Lag Equation (1975) <br />Developed for small (<2000 acres) watersheds <br />Equation assumes Tc = 1.67*Basin Lag <br />Tc = 10OL0'8[(1000/CN)-9]1.7 / (1900So.1) <br />Avg. slope for longest watercourse S = 17.8 <br />SCS Curve No. CN = 84 <br />Length of Water Course L = 1,625 <br />Tc = 10 <br />Parkdale Sand and Gravel Pit <br />F <br />Acres <br />Square Miles <br />A, B, C, or D <br />Land use assumed to be Pasture/Range in FAIR condition <br />feet <br />minutes