Design a sag inlet and a pipe to carry the runoff developed in Problem 16.4 under future conditions. Assume the pipe will be concrete and will run on the same slope as the ground slope. Problem 16.4 A...

Design a sag inlet and a pipe to carry the runoff developed in Problem 16.4 under future conditions. Assume the pipe will be concrete and will run on the same slope as the ground slope.

Problem 16.4

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.