Civil 3D software to automate design and analysis of storm sewer networks with Hydraflow Extension tools. Site layout analysis….We’ll use AutoCAD software and Civil 3D to prepare data such as watershed and catchment areas, and lay out a drainage network for further analysis of hydrology and hydraulic in Hydraflow Extension. We’ll analyze hydrology, open channel flow, and culvert and pipe flow. We’ll also design detention ponds. And we’ll generate stage-storage curves, pond routing, and outflow hydrographs. We’ll use site-grading tools and corridors to complete design modeling.