The variation of the coastal groundwater table and the vulnerability of sanitary sewer infrastructure under a changing climate is considered for Imperial Beach (CA, USA) by incorporating the compound impacts of SeaLevel Rise (SLR), groundwater shoaling, and precipitation intensification. For 2 m of SLR, marine inundation is expected to impact only 2% of the urbanized area; however, SLR-driven groundwater shoaling is projected to impact 36% of the subterranean sewer system. Due to GroundWater Infiltration (GWI) and Rainfall-Derived Inflow and Infiltration (RDII), the sanitary sewage flow increases by 21% and 49% during dry- (i.e., consecutive days without precipitation) and wet-weather conditions (i.e., 24-hour rainfall with a 25-year return period), respectively. At SLR = 2 m, defect flows (GWI + RDII) can be elevated by 84% and 120% in dry- and wet-weather conditions, respectively. Such elevated hydraulic loads may place $0.5-$2.7 M additional cost on the collection system and treatment facilities every year. Moreover, pressurized junctions due to the above-mentioned hydraulic loading are likely to expose the community and the environment to raw sewage pollution. By involving structural, hydrological, and hydraulic criteria, a holistic approach is presented and implemented for prioritizing sewer system rehabilitation.
Sangsefidi, Y; Barnes, A; Merrifield, M; Davani, H
Data-driven analysis and integrated modeling of climate change impacts on coastal groundwater and sanitary sewer infrastructure
Sustainable Cities And Society