Preliminary findings indicate generally good water quality in most surface waters within the park. Most of the water bodies and wetlands in the park have major portions of their drainage basin upstream and outside of park boundaries. The park, in cooperation with researchers from the Virginia Institute of Marine Science conducted a study to investigate the effects of adjacent urban and agricultural development on the shallow groundwater and selected surface water resources of the park. Testing indicates potential local sources of groundwater contamination from nitrate and ammonia at several sites near Jamestown Island, Williamsburg and Yorktown. Salinity and phosphate concentrations were low or below detectable levels.