Surface Water Quality Regulation as a Driver for Groundwater Recharge

Abstract

Water scarcity commonly motivates managed aquifer recharge projects, but other factors can motivate recharge efforts, including in relatively water-rich areas. Surface water quality regulation has been a major driving force behind a large-scale recharge project in development in Virginia’s Coastal Plain region, where nutrient pollution from agricultural and urban sources has degraded the Chesapeake Bay’s ecosystems, leading state and federal regulators to require dischargers to reduce their nutrient contributions to the watershed over time. Hampton Roads Sanitation District is pursuing the Sustainable Water Initiative for Tomorrow, an innovative, multi-benefit initiative designed to address both nutrient pollution in the Chesapeake Bay watershed and regional groundwater overdraft in the Coastal Plain. When fully implemented, the initiative is expected to recharge approximately 100 million gallons per day of drinking-water quality, treated municipal wastewater into the Potomac Aquifer System through injection facilities located at five of the District’s wastewater treatment plants. As a result, the District expects to reduce its nutrient discharges from those plants by approximately 90%, enabling it to meet its own mandated nutrient limits while also generating nutrient credits that it can trade to other dischargers. Modeling suggests that the initiative will increase regional water pressure within the confined aquifer system, helping to combat groundwater overdraft and its negative impacts, including aquifer compaction and related land subsidence, falling water levels in wells, and saltwater intrusion. This case study provides insights into the influence of institutional context on managed aquifer recharge and on multi-benefit water resource projects more generally.

The role of nutrient credit trading for total maximum daily load compliance by the urban stormwater sector: Evidence from Virginia's Municipal Separate Storm Sewer Systems

“…Additional phase 2 MS4s were included from the southeastern portion of the state, as a regional wastewater treatment authority, the Hampton Roads Sanitation District (HRSD), TA B L E 1 Attributes and co-benefits of compliance options available to Municipal Separate Storm Sewer Systems (MS4s). has offered to cover MS4 Bay nutrient permit compliance requirements by supplying point source term credits for free (NACWA, 2018;Nylen, 2021). Five of the largest individual permit holders, only one of which was operating under phase 2 (40%) reduction requirements, were also included.…”

Demonstration of Managed Aquifer Recharge in a Coastal Plain Aquifer: Lessons Learned

“…Unlike other indirect potable reuse MAR projects including aquifer storage and recovery (e.g., Pyne 2005), SWIFT is designed for continuous recharge with no intentional reuse or recovery. Other potential benefits of the SWIFT Project include reducing pumping‐induced land subsidence in the southeastern region of Virginia (Eggleston and Pope 2013) and inhibiting saltwater intrusion in the PAS (Nylen 2021).…”