I am new to Civil 3D and Hydraflow. My question is this: I have an 4.5 acre site that is going to be paved and have subsurface drainage (culverts w/ catch basins) installed. I can run my sheet flow for the existing undeveloped site, but how do you model the subsurface drainage into the pond. The smaller drainage areas will drain to each catch basin then the subsurface piping will convey the water to the detention pond. I only see sheet flow, shallow conc. flow and channel flow. Will the channel flow option in the TR-55 Worksheet accurately calculate a Time of Concentration for this?
Thank you,
