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Open-File Report 2007-1205

USGS Publications Warehouse

# A Science Plan for a Comprehensive Regional Assessment of the Atlantic Coastal Plain Aquifer System in Maryland

By Robert J. Shedlock, David W. Bolton, Emery T. Cleaves, James M. Gerhart, and Mark R. Nardi

**Prepared in cooperation with**    Maryland Geological Survey and the    Maryland Department of the Environment 

## Abstract

The Maryland Coastal Plain region is, at present, largely dependent upon ground water for its water supply. Decades of increasing pumpage have caused ground-water levels in parts of the Maryland Coastal Plain to decline by as much as 2 feet per year in some areas of southern Maryland. Continued declines at this rate could affect the long-term sustainability of ground-water resources in Maryland's heavily populated Coastal Plain communities and the agricultural industry of the Eastern Shore.

In response to a recommendation in 2004 by the Advisory    Committee on the Management and Protection of the State's Water Resources, the Maryland Geological Survey and the U.S. Geological Survey have developed a science plan for a comprehensive assessment that will provide new scientific information and new data management and analysis tools for the State to use in allocating ground water in the Coastal Plain. The comprehensive assessment has five goals aimed at improving the current information and tools used to understand    the resource potential of the aquifer system:
    -  (1) document the geologic and hydrologic characteristics of the aquifer system in the Maryland Coastal Plain and appropriate          areas of adjacent states; 
    -   (2) conduct detailed studies of the regional ground-water-flow system and water budget for the aquifer system; 
    -   (3) improve documentation of patterns of water quality in all Coastal Plain aquifers, including the distribution of saltwater; 
    -   (4) enhance ground-water-level, streamflow,        and water-quality-monitoring networks in the Maryland Coastal Plain; 
    -  and (5) develop science-based tools to facilitate sound management of the ground-water resources in the Maryland        Coastal Plain. 

 The assessment, as designed, will be conducted in three phases and if fully implemented, is expected to take 7 to 8 years to complete. Phase I, which was initiated in January 2006, is an effort to assemble all the information and investigation    tools needed to do a more comprehensive assessment of the aquifer system. The work will include updating the hydrogeologic framework, developing a Geographic Information    System-based aquifer information system, refinement of water-use information, assessment of existing water-quality data, and development of detailed plans for ground-water-flow and management models.

Phase II is an intensive study phase during which a regional ground-water-flow model will be developed and calibrated for the entire region of Maryland in the Atlantic Coastal Plain as well as appropriate areas of Delaware and Virginia. The model will be used to simulate flow and water levels in the aquifer system and to study the water budget of the system. The model analysis will be based on published information but will be supplemented with field investigations of recharge and leakage in the aquifer system. Localized and finely discretized ground-water-flow models that are embedded in the regional model will be developed for selected areas of heavy withdrawals.

Other modeling studies will be conducted to better understand flow in the unconfined parts of the aquifer system and to support the recharge studies. Phase II will also include selected water-quality studies and a study to determine how hydrologic and water-quality-monitoring networks need to be enhanced to appropriately assess the sustainability of the Coastal Plain aquifer system.

Phase III will be largely devoted to the development and application of a ground-water optimization model. This model will be linked to the ground-water-flow model to create a model package that can be used to test different water-management    scenarios. The management criteria that will be used to develop these scenarios will be determined in consultation with a variety of state and local stakeholders and policy makers    in Phases I and II of the assessment.

The development of the aquifer information system is a key component of the assessment. The system will store all relevant aquifer data and appropriate ancillary data in a spatially referenced database. This system will be designed to serve the needs of both water managers and scientific investigators.

The system, when fully developed, is envisioned as a web-based tool and will facilitate the use of ground-water management models for evaluation of a variety of water-    management strategies.

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

**View           the full report in PDF (4.4 MB)**

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## Contents

        - Abstract
        - Introduction                       - Water Management Issues and Assessment Questions
          - Needs for a Comprehensive Regional Assessment                             - Significant Declines in Ground-Water Levels
            - Compromised Water Quality in Some Areas
            - Inadequate Information Systems and Tools 
        - Description of the Aquifer System                       - Hydrogeologic Framework
          - Ground-Water-Flow Patterns
          - Water Chemistry and Quality 
        - Description of Science Goals and Study Activities                       - Science Goal 1: Geologic and Hydrologic Characteristics of the Aquifer System                               - Need for New Work
            - Proposed Study Activities 
          - Science Goal 2: Ground-Water-Flow System and Water Budget                             - Need for New Work
            - Proposed Study Activities 
          - Science Goal 3: Ground-Water Quality                             - Need for New Work
            - Proposed Study Activities 
          - Science Goal 4: Monitoring Networks                             - Need for New Work
            - Proposed Study Activities 
          - Science Goal 5: Tools for Improved Management of the Ground-Water Resources                             - Need for New Work
            - Proposed Study Activities 
        - Implementation Plans                       - Phase I-Getting Started and Building Partnerships
          - Phase II-Filling in the Gaps and Building the Resource-Management Tools
          - Phase III-Using the Tools to Manage and Optimize the Resource 
        - Products and Benefits
        - Program Coordination and Outreach
        - Concluding Remarks
        - Acknowledgments
        - Selected References

## For more information about USGS activities in Maryland,         Delaware        and the District of Columbia contact:

Director      MD-DE-DC Water Science Center      U.S. Geological Survey      5522 Research Park Drive       Baltimore, MD 21228

 Telephone: (443) 498-5500      Fax: (443) 498-5510

or access the USGS Water Resources of Maryland, Delaware,      and       District of Columbia home page at:  http://md.water.usgs.gov/.

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U.S. Department of the Interior |		U.S. Geological Survey		URL: https://pubs.usgs.gov/of/2007/1205/		For more information, contact: webmaster@md.water.usgs.gov		Maintained by:  USGS Publishing Network 		Page Last Modified: Wednesday, 07-Dec-2016 20:30:56 EST