Integrated Plan Combining House-Level I/I Mitigation Program and GI Technology to Avoid Street Flooding – Case Study: Newton-Bedford Blueprint Columbus

Blueprint Columbus program is an integrated plan by the City of Columbus, Ohio designed to mitigate sanitary sewage overflow(SSO), manhole flooding (MH Flooding) and he potential incidents of basement backups. The mitigation technology selected by the City is source reduction for the Inflow and Infiltration (I/I) through lining the sewer mains and lateral house connections, roofs drainage redirection to the street, and storm water sump pumps. A green infrastructure (GI) program will be implemented to mitigate the additional surface stormwater because of the I/I reduction. The GI program will also provide water quality volume (WQv) control and remove at least 20% of total suspended soil (TSS).The City adopted “Model at the Source” house-based hydrologic and hydraulics model (H/H model) approach by Dr. Gheith to plan the integrated plan program. The modeling approach tracks the groundwater fluctuation in the aquifers around houses and the trenches around the lateral and main sewers and predicts the I/I peak flow and volume at these sources. The Model at the Source platform also supports both tracking the improvements in the sanitary system and quantifies the additional street flow because of the I/I reduction activities.The City of Columbus produced a Stormwater Modeling Manual for Blueprint Columbus in which the Model at the Source approach is enhanced with the addition of street channels, the incidental street ponding and the limitation of the storm inlets. LiDAR data is used to obtain the street cross section and the ArcGIS Sink Analysis is used to identify the streets incidental ponds. Field investigation is performed to obtain storm inlets configuration. The updated model is used to calculate the street stormwater flow at a high level of accuracy as well as the expected street flooding spread. This in turns allowed for effective planning for the GI program.This paper details the steps taken to plan and implement the Blueprint Columbus program to the Newton-Bedford study area. The paper will detail the I/I modeling approach, the procedure to predict I/I removal and the impact of additional storm water on the street channels and incidental ponds. It also details the modeling and sizing the proposed GI program.