INFLOW AND INFILTRATION REDUCTION STUDY AND SANITARY SEWER MODELLING-PROJECT DESCRIPTION

Civica was retained by the Town of Amherstburg (the Town) to complete an Inflow and Infiltration (I&I) reduction study and sanitary sewer modelling. The objective of I&I investigations in the study areas was to identify possible sources of inflow into the sanitary sewer, which were prioritized by the Town for rehabilitation. To meet the field investigation objectives, an extensive field investigation program was developed to identify I&I contributions into the Town’s sanitary sewershed for targeted catchments with high I&I and previous reports of flooding. Civica was also responsible for selecting and building the sanitary sewer system model, which involved data collection (i.e. background study, flow, rainfall, and asset data), data analysis, hydrodynamic model development and calibration, sanitary capacity analysis under existing and future scenarios, and solution development. As part of the scope of this project, sixteen (16) flow monitors, eight (8) sewer mainline and eight (8) sewage pumping station (SPS), were installed to establish dry-weather flow (DWF) patterns and assess the wet-weather response in each sewershed within the study area. These stations were incorporated into the model in order to calibrate it to the observed conditions. For areas where flow monitoring indicated high levels of I&I, field investigations were undertaken and forty-three (43) defects were identified including catch basins, cleanouts, downspouts, and surface water drains. Potential peak flow from the identified sources was estimated at approximately 81 L/s.