Surface Water Quality Regulation as a Driver for Groundwater Recharge

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.

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Surface-water quality in agricultural watersheds of the North Carolina Coastal Plain associated with concentrated animal feeding operations

Scientific Investigations Report ◽

10.3133/sir20155080 ◽

2015 ◽

Cited By ~ 7

Author(s):

Stephen L. Harden

Keyword(s):

Water Quality ◽

North Carolina ◽

Surface Water ◽

Coastal Plain ◽

Surface Water Quality ◽

Agricultural Watersheds ◽

Concentrated Animal Feeding Operations ◽

Animal Feeding Operations ◽

The North ◽

Animal Feeding

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Agricultural managed aquifer recharge — water quality factors to consider

California Agriculture ◽

10.3733/ca.2020a0020 ◽

2020 ◽

Vol 74 (3) ◽

pp. 144-154 ◽

Cited By ~ 1

Author(s):

Waterhouse Hannah ◽

Bachand Sandra ◽

Mountjoy Daniel ◽

Choperena Joseph ◽

Bachand Philip A.M. ◽

...

Keyword(s):

Water Quality ◽

Managed Aquifer Recharge ◽

Wine Grape ◽

Aquifer Recharge ◽

Quality Factors ◽

Soil Permeability ◽

Salt Leaching ◽

Groundwater Overdraft ◽

Irreversible Reduction ◽

Almond Orchards

The resilience and productivity of California's agriculture is threatened by groundwater overdraft, reduction in aquifer water quality, increased land subsidence damage to infrastructure and an irreversible reduction in groundwater storage capacity. Intentionally flooding agricultural fields during winter — a practice referred to as agricultural managed aquifer recharge (AgMAR) — can help counteract overdraft. However, the potential for AgMAR to exacerbate nitrate/salt leaching and contamination of at-risk aquifers remains a critical concern. To quantify the risk of groundwater contamination with AgMAR, we took 30-foot-long soil cores in 12 almond orchards, processing tomato fields and wine grape vineyards on low- and high-permeability soils, measured nitrate and total dissolved solids concentrations and calculated stored nitrate-N. Wine grape vineyards on permeable soils had the least nitrate leaching risk observed. However, almond orchards and tomato fields could be leveraged for AgMAR if dedicated recharge sites were established and clean surface water used for recharge. Historical land use, current nitrogen management and soil permeability class are the main factors to consider before implementing AgMAR.

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Modeling managed aquifer recharge processes in a highly heterogeneous, semi-confined aquifer system

Hydrogeology Journal ◽

10.1007/s10040-019-02033-9 ◽

2019 ◽

Vol 27 (8) ◽

pp. 2869-2888 ◽

Cited By ~ 9

Author(s):

Stephen R. Maples ◽

Graham E. Fogg ◽

Reed M. Maxwell

Keyword(s):

Managed Aquifer Recharge ◽

Alluvial Aquifer ◽

Confined Aquifer ◽

Aquifer Recharge ◽

Confining Units ◽

Large Variability ◽

Aquifer System ◽

Groundwater Overdraft ◽

Aquifer Systems ◽

Coarse Texture

Abstract Widespread groundwater overdraft in alluvial aquifer systems like the Central Valley (CV) in California, USA, has increased interest in managed aquifer recharge (MAR). Like most clastic sedimentary basins, recharge to the productive semi-confined CV aquifer system remains a challenge due to the presence of nearly ubiquitous, multiple confining units (silt and clay) that limit recharge pathways. Previous studies suggest the presence of interconnected networks of coarse-texture sand and gravel deposits that bypass regional confining units over a small fraction of the CV near the American and Cosumnes rivers. Here, variably saturated infiltration and recharge processes were simulated across a domain that includes high-resolution representation of the heterogeneous alluvial geologic architecture in this area. Results show that recharge potential is highly dependent on subsurface geologic architecture, with a nearly 2 order-of-magnitude range of recharge across the domain. Where interconnected coarse-texture recharge pathways occur, results show that these features can (1) accommodate rapid, high-volume MAR and (2) propagate widespread and rapid pressure responses over multi-kilometer distances in the semi-confined aquifer system. For all MAR simulations, results show that the majority of MAR is accommodated by filling unsaturated-zone (UZ) pore volume. Results also show that coarse-texture UZ facies (where present) accommodate the majority of MAR volume during early time, but fine-texture facies ultimately accommodate the majority of the total MAR volume, even for coarse-dominated sites. These findings highlight the large variability of MAR potential across the landscape and demonstrate the importance of fine-texture facies for accommodating MAR in alluvial aquifer systems.

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