Workplans on Study Design - Surface-Water Studies

Science Center Objects

The National study design for surface water focuses on water-quality conditions in streams by using three interrelated components: water-column studies , bed-sediment and fish-tissue studies , and ecological studies. Water-column studies are used to monitor physical and chemical characteristics such as suspended sediment, major ions, organic carbon, dissolved pesticides, and nutrients to determine their relation to hydrologic conditions, contaminant sources, and transport processes. Bed-sediment and fish-tissue studies are used to assess the presence and distribution of trace elements and hydrophobic organic contaminants that are less likely to be found in surface-water samples. Ecological studies are used to evaluate the effects of physical, chemical, and habitat characteristics on biological communities. Ecological surveys are done along a delineated stream reach and include a habitat assessment of the site and annual surveys of the fish, algal, and benthic invertebrate communities.

NAWQA sampling is conducted primarily at "basic-fixed" sites and "intensive-fixed" sites, which differ in the frequency of the sampling. The sampling sites are selected to determine the quality of water in important environmental settings in the study unit. Most NAWQA study units have 8 to 10 basic-fixed sites and 2 to 3 intensive-fixed sites. Surface water is sampled at basic-fixed sites monthly, and during selected high-flow conditions, for 2 years of the 3-year high-intensity phase. Intensive-fixed sites are monitored more frequently (as often as weekly during key periods) for at least 1 year of the high-intensity phase to characterize short-term variations in water quality. Aquatic biological communities are surveyed and bed-sediment and fish-tissue samples are collected at the basic-fixed and intensive-fixed sites during the 3 years of high-intensity sampling.

Basic-fixed sites and intensive-fixed sites can be either "indicator" or "integrator" sites. Indicator sites drain relatively homogeneous, small basins (less than 100 mi2) associated with specific environmental settings, such as a particular land use that substantially affects water quality in the study unit. Integrator sites are established at downstream points in large (thousands of square miles), relatively heterogeneous drainage basins with complex combinations of land-use settings. Indicator sites typically are located within the drainage basin of an integrator site.

Additional water, ecological, and bed-sediment and fish-tissue samples are collected as part of short-term synoptic investigations of specific water-quality conditions or constituents to increase spatial coverage and to allow investigators to evaluate how the quality of water at basic-fixed and intensive-fixed sites is related to the quality of water in other streams throughout the study unit.

Basic Fixed Sites

The Delaware NAWQA is using 10 fixed sites for our surface water studies. This includes 4 integrator sites and 6 indicator sites (2 urban and 4 agricultural sites). Population and land use information for these sites can be found in the table . Surface water is sampled at basic-fixed sites monthly, and during selected high-flow conditions, for 2 years of the 3-year high-intensity phase. Bed sediment and fish tissue is collected once at each site during the study. Ecological work at each site includes invertebrate sampling and algae sampling, and fish community and habitat assessments.

Integrator sites

Integrator sites for the Delaware NAWQA Study Unit are located at or near the confluence of major tributaries in the Delaware basin. This includes the Upper Delaware River at Port Jervis, NY; the Lehigh River near Easton, PA; the Delaware River at Trenton, NJ; and the Schuylkill River at Philadelphia, PA. The Port Jervis station integrates many of the streams in the Appalachian Plateau region that combine to form the main stem of the Delaware. The Lehigh River flows mostly through the Valley and Ridge Province and is headwatered in a mining region. It drains extensive areas of agricultural land, and has a moderate sized urban area (Allentown and Easton, PA) near its confluence with the Delaware River. This site currently has continuous water quality monitoring (specific conductance, temperature, and dissolved oxygen) for 6 months of the year (April to September). The Trenton station is a head-of-tide location for the Delaware Estuary and drains over 50 percent of the basin. It integrates all of the Appalachians, most of the Valley and Ridge, and parts of the New England and Piedmont Provinces. This is a former NASQAN site and has a continuous water quality monitor (sc, t, do, pH). The integrator site at Philadelphia, PA is a head-of-tide station and a discontinued NASQUAN site. The Schuylkill River is separated from the other drainages by the tidal estuary. The river drains over 15 percent of the basin and flows through the Valley and Ridge and Piedmont Provinces. As with the Lehigh it moves through mining, agriculture, and an urban area (Reading, PA) in the Valley and Ridge before entering the Piedmont. It then moves through more agricultural land before entering the Philadelphia metropolitan region where it discharges to the estuary. Many cities along the Schuylkill use the river as a source of drinking water and for the discharge of sewage effluent.

Indicator sites

Existing active and inactive gaging stations, as well as some non-gaged sites, were evaluated as potential indicator sites. A list of potential sites was developed using GIS coverages of land use (1992), geology, and point source intakes and discharges. Team members then met with state and federal representatives with knowledge of the area to discuss these sites and any others they might suggest. Potential sites were visited by team members in the Spring of 1998. When selecting sites we tried to nest indicator sites within integrator sites whenever possible. We also tried to integrate our groundwater studies within our fixed site network.

Urban -- We currently have 2 urban fixed sites: one in the clastic rocks of the Piedmont (Little Neshaminy) and one in the Coastal Plain (Cooper River). These sites address issues of urban growth in a major metropolitan area. Our criteria for selecting urban indicator sites included: (1) basin area greater than 50 km2, (2) urban land use over 50% of basin, (3) located in a rapidly growing newly urbanizing area (vs. old industrialized city), (4) contains less than 10% agricultural land, and (5) no major point source inputs.

Agriculture -- We currently have 4 agricultural fixed sites. One in the Coastal Plain (Raccoon Creek), one in the Piedmont (French Creek), and 2 in the Valley and Ridge (Tuplehocken Creek and Jordan Creek). Our criteria for selecting agricultural indicator sites included: (1) area greater than 100 km2, and (2) targeted land use over 50% of basin, (3) urban land covers less than 10% of the basin, and (4) no major point source inputs.

Intensive Fixed Sites

We currently have three intensive fixed sites. The Schuylkill River is an intensive integrator site, the Little Neshaminy River is an intensive urban indicator site, and Tuplehocken Creek is an intensive agricultural indicator site. Intensive-fixed sites are monitored more frequently (as often as weekly during key periods) for at least 1 year of the high-intensity phase to characterize short-term variations in water quality. Additional water quality constituents are also sampled at intensive sites.

Schedule of Fixed Site Work in FY 1998-2001

A preliminary schedule for surface water activities is shown in the table. Surface water sampling began at all sites in November 1998 and will continue until at least the Fall of 2000. Intensive sampling began at our fixed sites in February 1999 and will continue through at least June 2000. Spring high flow and summer storm event sampling will also be conducted at all fixed fixed sites.