Purdue University (Purdue) owns and operates the storm and sanitary infrastructure within the campus limits and utilizes an XP-SWMM model to aid in making decisions about campus changes that may affect the systems. Updates are needed often to both the existing storm and sanitary system models to reflect the present campus conditions. The significant growth and the redevelopments that occurred between 2006 and 2023 indicated a need for this Campus Sewer Modeling Study.
A total of 43 storm and sanitary flow meters and two rain gauges were installed between October and December 2021. The flow meter data was reviewed and used to derive transpired dry and wet-weather flows which were then used to calibrate both system XP-SWMM models. The Sanitary Sewer Overflow Analysis Planning (SSOAP) toolbox was utilized to determine hydrological parameters using the RTK method to predict the rainfall derived inflow and infiltration (RDII). These hydrological parameters were then entered into the sanitary model and multiple iterations of model runs were completed to calibrate and update the existing sanitary model in order to reflect the present situation.
Current and future conditions were modeled and analyzed. Future conditions showed a need for storm sewer improvements. Combinations of improvements were analyzed to alleviate some of the stress on the system. Bioretention, underground detention, detention basins and rerouting some of the system to the Todd’s Creek watershed were all considered. Improvements to the sanitary sewer system were also evaluated. The future conditions model allowed us to assess the impact to the downstream combined sewer system as the sanitary flows leave campus. All recommended future improvements projects included summaries of resulting flows and cost estimations.
Read More
