Yorktown Battlefield and visitor center

Project Title: Colonial National Historical Park Number: VA125 Location: Yorktown Cooperating Agencies: National Park Service Project Chief: Gary Speiran Period of Project 1999 to 2000

Springs discharging from the Cornwallis Cave aquifer

Problem
Surficial aquatic habitats share an obvious and dependent relationship with the ground-water system at Colonial National Historical Park (CNHP).  Consequently, successful management of park resources depends, in part, on knowledge of the quantity and quality of ground-water discharge.  Because ground water in the park can be influenced by off-park activities, the National Park Service (NPS) is concerned about activities outside the park boundaries that could adversely impact park resources. Specifically, the NPS is concerned about impacts that could degrade water quality, change  patterns of stream and spring flow, and/or endanger water-dependent biological resources. In order to effectively manage park water resources and minimize potential adverse impacts from outside park boundaries, a more complete understanding of the behavior of the park’s shallow aquifer system is needed.  Specifically knowledge is needed of:  

-The physical composition of the shallow aquifer system

-The depth, thickness, and lateral extent of significant aquifers and confining units

-The boundaries of surface-water and ground-water flow systems that encompass the park

-The ground-water recharge areas and general residence times

 -The interaction between the ground-water and surface-water systems

Objective
The primary objective of this study wass to develop an understanding of hydrogeologic framework and flow system of the Yorktown Battlefield shallow aquifer system to the extent possible using existing information and limited non-intrusive data collection methods.  The secondary objective was to identify significant gaps in local hydrogeologic information and provide a well-defined scope of work for future studies to address these data gaps.

Relevance and Benefits
Understanding of the shallow ground water near the Yorktown Battlefield will help the National Park Service, the Yorktown Naval Weapons Station, the town of Yorktown, and the City of Newport News protect and manage the shallow ground-water system.  This understanding will help the Park Service evaluate whether changes in water quantity or quality result from activities in the park or surrounding areas and manage such effects on stream-water quality, wetlands, and water-dependent biological resources.

Approach
Compiled existing hydrogeologic data for the Yorktown Battlefield unit of the park and    surrounding areas.

Performed a limited, non-intrusive hydrogeologic investigation of the park and its adjacent areas based on evaluation of existing data.

Constructed a shallow hydrogeologic framework, described aquifers and confining units, described general ground-water quality, and characterized the interaction between ground water and surface water.

Developed GIS coverages of pertinent data locations

Prepared a final report which, in addition to study results, includes project statements and cost estimates for intrusive data needs and further hydrogeologic characterization.