Water
Quality on the Delmarva Peninsula
Delmarva Peninsula |
Problem
The major water-quality
issues on the Delmarva Peninsula are contamination of shallow aquifers and in the rivers and estuaries surrounding the
Peninsula. Agricultural practices have the most widespread effects on water
quality because of the dominance of crop production and the poultry industry.
There is also concern about ground-water contamination from domestic and
community septic systems, as many of these systems are located in the surficial
aquifer in areas where it is used as a drinking-water source. Most of the
contamination problems in the estuaries surrounding the Peninsula are attributed
to contamination from agricultural chemicals and disposal of sewage
from small towns and industries, as well as private septic systems.
Objectives
Previous NAWQA
study on the Delmarva Peninsula from 1987-1991 helped to answer many important
questions about the effects of agricultural applications of fertilizers, manure,
and pesticides on both ground-water and surface water quality. We have the
opportunity to further develop our understanding of the effects of agriculture
on water quality as the NAWQA Program returns to the Delmarva Peninsula to
resume study unit activities. The major objectives of continuing work on the
Delmarva Peninsula are:
1. Study of
drinking-water issues, including trends in the quality of ground water with
respect to nutrient and pesticide contamination, and exploration of the effects
of emerging contaminant issues (including radium and poultry feed additives),
2. Integrated
assessment of the effects of agriculture with intensive poultry production on
ground-water and surface-water quality, and
3. Regional-scale seasonal synoptic sampling of
surface-water base flow to relate surface-water quality to hydrogeologic and
landscape gradients, and to relate shallow ground-water quality to surface-water
quality over the study area.
Relevance and Benefits
Approach
Several
major work elements that overlap in time will be performed. Study of
drinking-water issues will be incorporated into study of ground-water trends and
emerging contaminant issues (including radium in ground water and poultry feed
additives in ground water and surface water) at both local and regional scales.
Well networks from the previous NAWQA pilot project will be re-sampled to
explore changes
in the
transport of chemicals in ground water since the previous study. Wells from
community water systems will also be sampled. Two watersheds representing
different hydrogeologic conditions on the Peninsula will be studied in depth as
part of the integrated assessment component using flow-path studies,
surface-water sampling, geologic interpretation, and ground-water flow modeling.
Regional synoptic surface-water base flow sampling will be done to relate the
effects of agricultural practices and landscape patterns to surface-water
quality.
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