Preliminary Evidence That Rising Groundwater Tables Threaten Coastal Septic Systems

Comparison of Nitrogen Treatment by Four Onsite Wastewater Systems in Nutrient-Sensitive Watersheds of the North Carolina Coastal Plain

“…Wastewater in urban areas is typically treated via centralized sewer plants which are required to monitor influent and effluent characteristics including N concentrations [14]. Wastewater in rural areas is often managed via OWSs, but routine monitoring for nutrient treatment is not required for these technologies [15,16]. In the United States, approximately 23% of the population use OWSs, and in some states, such as North Carolina (NC), nearly 50% are served by OWSs [13,17].…”

“…The goal of this study was to provide more information on the N treatment efficiency of OWSs in North Carolina, where nearly 50% of the state's population use OWSs [17] and excess nutrient loading has caused eutrophication and the impairment of water resources [12]. This research may be applicable for regions that continue to rely heavily on OWSs for new development and have nutrient-sensitive waters such as the eastern and Gulf Coast of the US [14,15,23,24], Canada [39,40], Australia [41], and Ireland [31,32].…”

Onsite and Decentralized Wastewater Management Systems

“…However, many regions are experiencing water table elevation changes due to changes in precipitation patterns, sea level rise, recharge from onsite wastewater systems, or imports of out-ofbasin potable water. Cox et al (2019) carried out an analysis of Fig. 1.…”

Geospatial Modeling Suggests Threats from Stormy Seas to Rhode Island’s Coastal Septic Systems

“…Additionally, using flood depth on each parcel, in addition to overall coast-wide flooding extents would likely result in a more refined model to be created, which might help explain the remaining differences between the observed damage and the model's predicted damage categories. Finally, accounting for long-term changes to groundwater tables in response to SLR and other human impacts to groundwater use and recharge in the area (Cox et al 2019;Sukop et al 2018;Walter et al 2016) could improve the model's predictive power as well.…”

“…A regional probabilistic Coastal Environmental Risk Index (CERI) assessment has been developed to model aboveground structural damage to coastal buildings (Spaulding et al 2016), but this model does not predict duration of flooding, nor does it assess damage to below-ground infrastructure like OWTS. Nearly all homes along the southern RI coast rely on individual OWTS to treat domestic wastewater (Cox et al 2019). Given that OWTS drainfields require unsaturated conditions to function properly , accounting for the temporal dynamics of the inundation events mapped by the aforementioned tools is critical to understanding how coastal OWTS are likely to be impacted by such events.…”