Delaware River Basin NAWQA Study
DELAWARE RIVER BASIN NAWQA WORKPLAN
USGS IN YOUR STATE
USGS Water Science Centers are located in each state.
Workplans on Study Design—May 1999
During NAWQA studies 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. For the Delaware NAWQ study the design of synoptic surveys will be guided by results of our retrospective analysis and input from our liaison committee, USGS district personnel, and members of the NAWQA National Synthesis Teams.
Synoptic sampling plans for 1999 are listed below. Also listed are some preliminary ideas for future synoptic surveys. Plans for future synoptic surveys are not complete and subject to change.
Synoptic Survey Plans for 1999
Reservoir release synoptic - Reservoir releases comprise a significant part of the flow on the Delaware River, particularly at low flows (figure). Power releases can change flows on a daily basis by over 1000cfs. These releases could have significant impacts on water quality. The releases could affect our interpretation of data being collected at our Port Jervis and Trenton fixed sites. To assess the impacts of reservoir releases on water quality in the Delaware River we plan to conduct temporal sampling ever 3 to 4 hours for nutrients, major ions, and dissolved and suspended organic carbon at Port Jervis over 2 to 3 days. This sampling would be augmented with continuous monitoring of temperature, pH, conductance, turbidity, and dissolved oxygen. Periodic sampling may also be conducted for pesticides.
Basin-wide synoptic - The objective of this synoptic is to assess water quality throughout the basin and to test techniques to be used in future land-use gradient synoptics. Sampling will concentrate larger tributaries (map) throughout the basin and will be conducted during high base flows in the Spring and repeated at low base flows in the Summer. Constituents to be sampled include nutrients, major ions, pesticides, and dissolved and suspended organic carbon. Ecological assessments (including invertebrate, algae, and chlorophyll sampling combined with a modified habitat assessment) will be conducted at each site. Some bed sediment and fish tissue sampling will be integrated with this and later land-use synoptic sampling. (table of constituents for synoptic sampling). This synoptic will be completed by September 1999.
Preliminary Plans for Future Synoptic Surveys
Land-use gradient synoptics - The Delaware River Basin has many agricultural and urban areas that impact water quality and ecology. To look at these impacts we propose to select 20 to 30 sites in each of the 4 major regions (Appalachian, Valley & Ridge, Piedmont, and Coastal Plain) for a total of 80 to 100 sites. Sites in each region would be selected along a land-use gradient. For instance sites along an urban gradient would range from 0 to 60 percent urban (the upper limit of urbanization in the basin). Synoptic data will be used, in conjunction with the fixed-site data, to examine water quality and ecological community responses to different levels of urbanization. The synoptic surveys will provide a spatial context within which to place the fixed sites. The fixed sites will provide a temporal context (monthly and yearly variation) in which to examine the synoptic data. Together these data sets will allow us to better describe the urban gradient than with fixed sites or synoptic sites alone. We propose to conduct low-flow and high-flow surveys of nutrients, pesticides, microbiology, and suspended sediment at all sites. Ecological surveys will be conducted at all synoptic sites during low-flow conditions. Ecological components would be a subset of those collected at fixed sites, and would probably include periphyton, habitat, and benthic invertebrates. We would like to include fish-community surveys at some sites, and might be able to link with other agencies or organizations to have some of this work done as a joint effort. Additional bed sediment and fish tissue work would also be coordinated with this activity.
PCB synoptic - PCBs are the main reason for fish advisories in the estuary. Recent work by the Delaware River Basin Commission indicates that PCBs are mobilized during high flow events. To better understand the loadings of PCBs to the estuary we would sample our fixed sites on the Schuylkill and Delaware for PCB congeners at various flow conditions several times during the year.
Additional reservoir release synoptics - If results from our initial reservoir release synoptic indicate there are significant changes in water quality related to reservoir releases the study will be repeated at Port Jervis and possibly some down-stream sites. We may also try to follow a slug of water down stream to look at how water quality changes in response to dilution, degradation, and other factors. To interpret data from our fixed sites it may be necessary to model flow. The flow and transport models most likely to be used are DAFLOW and BLTM, respectively; both are USGS models. This work would be crucial to understanding and interpreting our main-stem integrator site sampling. If this synoptic is conducted it will occur between the Spring and Fall of 2000.