Groundwater Resources Management on the Atlantic Coastal Plain: Recommendations for Improved Sustainability

The states of the Mid-Atlantic Region allocate, manage and protect groundwater resources in the confined aquifers of the Atlantic Coastal Plain in accordance with the Reasonable Use Doctrine. This Doctrine both presumes and requires groundwater level management on a sustainable basis. Some Mid-Atlantic states have developed long-term management strategies focused on sustainable management and protection of these confined aquifers in perpetuity. Broadly these strategies define “management levels” below which regional water levels may not be lowered as a consequence of anthropogenic withdrawals.

Groundwater withdrawals have resulted in potentiometric declines over the last half century; historically these have been of little practical consequence.  Typical regional rates of decline are 1 to 2 feet per year; certain specific areas have experienced several times that rate of decline as a consequence of increased water supply utilization. In some locations, the magnitude of potentiometric drawdown has exceeded forecasts.  Growing instances of resource competition, domestic water supply system failures, potential salt-water intrusion and confined-to-unconfined transitions have occurred or are forecast.

Regulatory groundwater allocation and management strategies presume that groundwater use can be managed through increased agency intervention if/when potentiometric surfaces approach such levels. This presentation will review examples of such agency intervention. Numerical models have been developed and refined to assess withdrawal effects and forecast the amount of drawdown remaining above regulatory management levels. Because the incidence of excessive drawdown has been infrequent to date, robust model verification data are not yet available. 

This presentation will focus on specific areas of the Atlantic Coastal Plain with under-predicted drawdown to date, unmitigated well impacts and/or continuing groundwater use rates which appear unsustainable. Recommendations will be offered for groundwater management practices focused on perpetual sustainability.