Incorporating Storm Sewer Exfiltration into SWMM: Proof of Concept

This study evaluates the peak flow and volume reduction achieved by exfiltration from a perforated storm sewer in an urban catchment. There are three related objectives: [1] quantify peak flow and volume reduction; [2] demonstrate adaptability to climate change; and [3] evaluate economic feasibility. This paper reports on our progress with objective number one. The SWMM source code is modified to allow simulation of the storm hydrograph for controlled partial exfiltration from the sewer line. Simulations performed with the modified SWMM code enable evaluations of flow and volume reduction along links connecting adjoining nodes. Precipitation conditions are simulated with synthetic storm events generated from precipitation data for southwestern Ohio found in the Rainfall Frequency Atlas of the Midwest.