Volume of Storm Water Retention Basins

Storm water retention basins are becoming a more frequent part of combined and separate storm water collection systems. A rational method for designing these basins was conceived and a system of tables and calculations was developed to implement the design. The method described was compared with the Colorado Urban Hydrograph Procedure (CUHP) currently used by some designers. Basic errors in the CUHP were pointed out. The method herein described develops the rainfall intensity versus the time relationship from a given rainfall versus duration relationship. From this, a discharge hydrograph is computed for a given area and a given time of concentration. The discharge hydrograph is then routed through the retention basin by conventional means.