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Basin Information and Lag Time Computation <br />Project Title: Parkdale Granite Quarry <br />Catchment ID: A <br />1. Catchment Hydrologic Data <br />Catchment ID = A <br />Area = 132.00 <br />Area = 0.2063 <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 = 100L° 5[(1000/CN)-9]0 71(1900So.5) <br />Avg. slope for longest watercourse S = 10 <br />SCS Curare No. CN = 84 <br />Length of Water Course L = 4,161 <br />Tc = 28 <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 (approx 2 hours)