Calibration of SWMM Runoff Quality Model with Expert System

Abstract

EPA'S storm water management model (SWMM) simulates urban runoff quantity and quality. An interactive program has been developed by using expert‐system technology to automate the calibration of the water‐quality parameters of the runoff block of SWMM. It acts as a front end in the estimation of the parameters and the buildup of the input files. Production rules are employed for the interpretation of the simulation results in order to suggest some useral adjustments of the significant parameters. The goal of the expert system is to obtain a set of parameters for which the predicted pollutant loads are close to the measured loads. The expert system has been tested on several watersheds, proving that it could perform the calibration but that a shortcoming exists in the model itself that cannot be alleviated through calibration. The Denver experiment showed that the same set of parameters is not valid for low‐ and high‐intensity events.