A drainage study describes the general hydraulic conditions for a drainage and storm water system during a 1:100 year storm event, including flood depths, hazard classification and flow rates. Oftentimes surveyed culvert and ground LIDAR data is cross referenced to confirm watershed (catchment) areas. Engineering models use historical studies of the watershed areas along with new data, to map drainage paths and evaluate the extents of flooded areas. They can be completed for a broader region and include general, high level information regarding drainage flow paths, important waterbodies and drainage channels and outlets. A drainage study can also be done for a specific development proposal to ensure there isn't a post development effect on drainage.
Corman Park has completed a number of drainage studies for broader areas and also requires them for single and multi parcel development. Some drainage studies are also being coordinated at the regional level through the P4G planning district.