Importance of Ground Water in the levels in confined aquifers to Atlantic Coastal Plain of Maryland decline by tens to hundreds of feet from their original levels (fig. round water is the primary source 3). The current rate of decline in Gof water supply in most areas of many of the confined aquifers is Maryland within the Atlantic Coastal Plain about 2 feet per year. The (fig. 1), and is pumped from sand and gravel declines are especially large in layers underlying the Coastal Plain. These southern Maryland and parts of sand and gravel layers alternate with layers the Eastern Shore, where of silt and clay to form a wedge-shaped ground-water pumpage is pro- system of sediments that begins at the Fall jected to increase by more than Line (the boundary between the Atlantic 20 percent between the years Coastal Plain and the Piedmont 2000 and 2030, with some regions Physiographic Provinces) and gently tilts experiencing significantly greater and thickens to the southeast toward the increases. Continued water-level Atlantic Ocean (fig. 2). The buried sands declines at current rates could and gravels form a sequence of confined affect the long-term sustainability aquifers that is overlain by sandy deposits of ground-water resources in that form a surficial aquifer. These aquifers Maryland’s heavily populated are the primary water supply for southern Coastal Plain communities and Maryland and the Eastern Shore. the agricultural areas of the Eastern Shore.

Why is this Assessment Necessary? 2) Water Quality in Some Areas ....is Significantly Compromised 1) Water Levels in the Aquifers are Water quality in the Coastal ....Declining at a Significant Rate Plain aquifers is a concern for Withdrawals from Maryland Coastal several reasons. Contamination Plain aquifers have caused ground-water by saltwater intrusion is a significant water- ground water is the water-supply source quality issue for the confined for many homeowners and provides much aquifers, and has been documented of the base flow to streams. in several of Maryland’s waterfront communities. However, the poten- 3) Ground-Water Resource Managers Need tial for saltwater intrusion is not well ....Better Tools known in the deeper parts of the Water managers, policymakers, plan- aquifer system because few data ners, and developers need to know how are available. Some areas have much ground water is available in the dif- problems with naturally high con- ferent areas of the Maryland Coastal Plain centrations of trace-element con- for public and domestic water supply, agri- taminants (including arsenic and culture, industry, and electric power gener- radium), and further evaluation of ation. Ground-water withdrawals in these public health issues is war- Maryland are managed by the Maryland ranted. Elevated concentrations of Department of the Environment (MDE) nutrients and agricultural chemicals through the Water Appropriations Permit in the surficial aquifer is a signifi- Program. While studies of individual cant concern, especially on the aquifers or multi-aquifer subregions are Eastern Shore, where shallow available, MDE needs more comprehensive

U.S. Department of the Interior USGS Fact Sheet FS 2006-3009 U.S. Geological Survey 2006 and interactive tools for making manage- ment and permitting decisions. Specifically, MDE needs information systems and simu- lation tools to evaluate the effects of increased withdrawals on the entire aquifer system in important subregions and throughout the Maryland Coastal Plain. These tools need to take into account that some of the aquifers are units of a regional system that extends into and is used for water supply in adjacent states. Evaluation of alternative water-man- agement strategies requires enhancements in the monitoring networks for ground- water levels and streamflow throughout the Coastal Plain. Water managers and plan- ners need to understand where and when continued withdrawal of ground water may reduce streamflow and/or induce changes in water quality that would require addition- al treatment or limit uses of the water resource.

Plans for the Comprehensive Assessment of the Coastal Plain Aquifer System in Maryland

In response to the Advisory Committee’s 2004 report recommendations, MGS and USGS are preparing a science plan and implementation plans for conduct- ing a comprehensive regional assessment of the Coastal Plain aquifers in Maryland and appropriate areas of surrounding states.

Comprehensive Assessment is Underway

MGS and USGS started Phase I of the Comprehensive Assessment in January 2006. Phase I activities are being jointly supported by funds and services from MDE, MGS, and USGS. Phases II and III of the assessment will require significant addi- tional investment from current and new funding partners from 2008 to 2013.