NAWQA: Study Components and Data
- Delaware Source Water Assesment Program
- Coastal Plain Major Aquifer Study
- Delmarva Agricultural Land Use
- Delmarva Major Aquifer Study
- Great Valley Land Use
- Piedmont Source Water Quality Assesment
- Piedmont Urban Land Use
Groundwater samples have been collected and analyzed in the Potomac River Basin and Delmarva Peninsula (PODL) as part of the NAWQA program since the late 1980s. Sampling programs are designed and implemented to support the major objectives of the NAWQA program, including evaluation of the status and temporal trends in water-quality conditions, and identification of natural and human factors affecting those conditions.
Groundwater sampling during the first 10-15 years of NAWQA activities in the PODL were directed largely toward evaluating spatial variability in groundwater quality among many of the diverse land-use and hydrogeologic settings that occur within the Potomac River Basin and Delmarva Peninsula. Sampling has been limited mainly to relatively shallow, unconfined groundwater, and was designed to: 1) evaluate effects of particular agricultural or urban land uses on recently recharged groundwater, and/or 2) estimate the distribution of pesticides, nutrients, or other chemicals in groundwater that is widely used for domestic or public supply. Effects of agriculture on shallow groundwater have been measured in the most intensively agricultural areas of the PODL, including the Delmarva Peninsula and the Great Valley, as well as in the Valley and Ridge. Effects of urbanization on groundwater quality have been evaluated in urbanizing areas of the Piedmont in the suburbs of Washington, DC. Regional groundwater quality has also been evaluated in major aquifers of the Piedmont and of theCoastal Plain along the Fall Line and on the Delmarva Peninsula. Studies of local-scale groundwater flow and quality have been conducted to supplement these regional investigations in the Great Valley and on the Delmarva Peninsula. Because groundwater typically flows very slowly, studies of temporal trends in groundwater quality as part of the NAWQA program are planned for an approximately decadal time scale.