Exploring the potential for groundwater inundation in coastal US cities due to interactions between sewer infrastructure and global change

Abstract

Urbanization, in particular, the culverting and burying of streams in sewer infrastructure, has affected both surface and subsurface flow regimes. While researchers have examined the impact of stream burial on groundwater budgets, field studies examining the influence of urbanization on groundwater dynamics are relatively scarce. This study analyzes tidal patterns in water-level data from shallow groundwater monitoring wells located next to a legacy sewer line within the city of Philadelphia, Pennsylvania, USA. The coupling of historic records, sewer network maps, and well bore hydrogeology explains spatial patterns in groundwater elevations. Furthermore, a synthesis of early twentieth century United States census data, and continental scale GIS data demonstrates the potential for groundwater inundation in coastal United States cities that are served by aging sewer infrastructure. Altered groundwater flow dynamics caused by sea level rise, coupled with climatic shifts will likely stress aging sewer infrastructure, and can lead to increased discharge of combined sewer overflow systems and flooding.