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| Albemarle-Pamlico NAWQA |
| ALBE | NAWQA | DATA | PUBLICATIONS | CONTACTS |
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| Albemarle-Pamlico NAWQA |
| ALBE | NAWQA | DATA | PUBLICATIONS | CONTACTS |
ABSTRACT:
The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program was established to answer the question "Is the Nation's water quality getting better, worse, or staying the same" - The Albemarle-Pamlico Study Unit, which includes four major river basins, the Chowan, Roanoke, Tar, and Neuse, was one of 20 study units, established in 1991 to help address this important question. By 1997 as many as 60 study units are targeted to be established on a national basis.
To identify major surface-water and ground-water-quality problems associated with nutrients and pesticides on both spatial and temporal scales, information is required to determine if these chemicals occur at concentrations and locations which are of environmental or human health concern. This information is obtained by active monitoring of surface and ground-water quality collection of samples from stream and well sites for analysis of chemical constituents and compounds of interest. This report concentrates on nutrients and pesticides.
SUMMARY AND CONCLUSIONS
Elevated concentrations of nutrients have been linked to eutrophication of rivers, lakes and the sounds. Determination of the relative contributions of surface water and ground water and specific land uses or activities to eutrophication and pesticide contamination are essential to evaluating and solving these water quality problems. The effects of pesticides in aquatic systems are not well known and the distribution and occurrence of many common pesticides are just now being determined. More water quality monitoring of rivers and ground water in the outer Coastal Plain is needed to complete a nutrient budget for the Albernarle-Pamlico Sounds.
Results from the Albermarle-Pamlico NAWQA indicate the following:
Fertilizer is the major source of nitrogen in all four basins, although it was lowest in the Roanoke Basin, the least agricultural.
Fertilizer and livestock are the major sources of inputs of phosphorus in all basins.
Although permitted point-source inputs of nitrogen and phosphorus account for less than 5 percent of inputs of these nutrients in all basins, nutrients from this source enter streams directly and can be a significant percentage of the instream load.
About 13,000 tons of nitrogen and 1,100 tons of phosphorus are transported as instream loads to the Albemarle-Pamlico Sounds from the Chowan, Roanoke, Tar-Pamlico and Neuse Basins annually.
The Neuse River and Contentnea Creek, which have the highest yields of nutrients, contribute the largest percentage of nitrogen and phosphorus to the sounds. The Neuse Basin alone accounts for almost half of the phosphorus entering the sounds although it represents only about 20 percent of the total contributing drainage area. Although the Roanoke River contributes 34 percent of the nitrogen, it has the largest drainage area, but has the lowest yields of both nitrogen and phosphorus.
Concentrations of nitrate are higher and concentrations of ammonia are lower in shallow ground water of the inner Coastal Plain than the outer Coastal Plain, indicating the importance of geochemical processes and soils in controlling nutrient concentrations in ground water.
Highest average concentrations of nitrate and phosphorus in surface water occurred in the Neuse Basin.
The higher incidence of pesticides and high pesticide concentrations in surface water of the Albemarle-Pamlico Drainage and lower incidence in ground water indicate that pesticides are primarily a problem in surface water as a result of contaminated runoff or atmospheric deposition and not to discharging ground water.
Herbicides such as metolachlor were detected in almost 90 percent, atrazine in 30 percent, prometon in 70 per cent, and alachlor in 65 percent of 233 surface-water samples collected in the Albemarle-Pamlico Drainage.
Spruill, T.B., Woodside, M.D., Harned, D.A., McMahon, Gerard, and Eimers, J.L., 1996, Results of the Albemarle-Pamlico drainage NAWQA—Nutrients and pesticides in surface water and ground water in Proceedings, Solutions—A technical conference on water quality: Raleigh, North Carolina State University, March 19-21, p. 24-30.
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