A I-acre lot is to be developed for residential dwellings. The original undeveloped condition is such that the longest watercourse length is 300 ft, the average slope is 3%, and the Manning n value of...

A I-acre lot is to be developed for residential dwellings. The original undeveloped condition is such that the longest watercourse length is 300 ft, the average slope is 3%, and the Manning n value of the ground cover is 0.1. After development, the n value reduces to 0.05. Assuming that the 24-hr two year rainfall depth for the area is 3.5 inches; use Figure 16.1 to estimate the peak storm water runoff for the IO-year event for this area under both present and future conditions. Use runoff coefficients of 0.25 and 0.6 for existing and improved conditions, respectively.