A Methodology for Calibrating SWMM Models

Computer simulation models of storm water systems have become established tools for predicting the hydrologic response of a watershed and evaluating the capacities of associated hydraulic conveyance systems. Their usefulness extends from the capacity to model complicated drainage systems to the ability to quickly analyze the impact of various storms and land use conditions. Obtaining maximum value from a computer analysis depends to a large degree on the quality of available data and the calibration techniques employed to relate the response of the computer model with the watershed and drainage system. Invariably, predicted :flood flows are extrapolated beyond available measured watershed response data. However, a well-planned model calibration effmt can result in a simulation model that is verifiable and truly representative of the physical system.