Developing and calibrating a large SWMM model in coordination with sewer cleaning and inspection can be a challenging, labor intensive and time consuming task. The common model calibration approach on closed conduit hydraulics involves estimating roughness coefficients and sediment depths throughout the sewer system. But, when detailed sewer condition parameters are available from televised inspections, and those conditions change throughout the calibration period due to sewer cleaning, the task becomes more complicated.
For the City of Columbus, Ohio’s Livingston/James Sewer System I/I Remediation Project, the project team developed a comprehensive tool to integrate the condition parameters of the sewers gathered from sewer inspection into the model calibration process by GIS and database applications. This new tool helped to shorten the calibration time and maintain accuracy, while accounting for approximately 43,000 sewer defects, including root balls and other blockages, in the calibration of the project’s 2,900-conduit SWMM EXTRAN model.