Mitigating the Volume of Inflow and Infiltration Entering the Sewage Network during the Storm of the Trunk Sewage Line (A Case Study in Karbala-Iraq)

Managing rainwater in light of climate variability is one of the most difficult problems facing urban areas in the world. Heavy rainfall contributes to increased infiltration of rainwater and effluent (RDII) into the sewage systems, which leads to system overflow and thus increased environmental pollution. This study aims at reducing the volume of surface runoff and thus reducing the volume of inflow and infiltration that enters the sewage network during the storm of the main sewage line of Karbala city. To investigate the extent to which the proposed solution would mitigate floods in the study area, the rainwater Management Model [SWMM] used data density for hourly precipitation from 2016 - 2019. The results indicate that the size of the flood was reduced to more than 75%, while the flood time decreased from 38 hours to 8 hours. The overload limit was reduced from 25 manholes to 5 manholes reduced (80%), and the excess duration were reduced by 55%. Total sanitary sewer overflow (SSO) 95m³ and area flooding 633m². This analysis is expected to provide a comprehensive solution to mitigate sewage flooding during a storm and provide support to decision-makers to reduce environmental and health problems during heavy rains.