Reducing the loading of "stressors" (pollutants) on watershed streams and lakes is the concern of a broad range of environmental stakeholders, including local and state governments, utilities, farm collectives, construction firms, and even homeowners. Their adoption of Environmental Protection Agency (EPA) best management practices (BMPs) for controlling both urban and rural sources of waterborne pollutants is helping to reduce contaminants at the watershed level. However, attempts to measure the effectiveness of specific watershed BMPs on stream ecology have been unsuccessful because they lacked a systematic framework for linking pollution reductions to in-stream biological conditions. National Risk Management Research Laboratory (NRMRL) water researchers are attempting to close that data gap with the operation of an experimental stream facility and watershed level monitoring program to test, apply, and calibrate results. The goal is to amass sound scientific evidence of how well management practices meet a desired biotic endpoint. The Experimental Stream Facility (ESF) in Clermont County, Ohio, is designed to provide a balance between the controlled conditions of the laboratory and the variability of the natural environment that is required to sustain natural communities. Fully automated, continuous flows of river water from the Lower East Fork River are delivered to eight 12-meter-long stream channels called mesocosms (an experimental system that simulates real-life conditions). The indoor mesocosm studies, complete with timed daylight simulations, are geared toward explaining the relationships between multistressor loads on biotic structure and functional responses. Studies are incorporated into a watershed-level research plan designed to characterize, track, and model water quality from BMP implementation projects. The outdoor supporting monitoring network ranges in scale from headwater streams to larger multiuse channels and reservoirs. EPA leases the ESF from Clermont County, and NRMRL scientists share space with the Clermont County Sewer District Water Quality Testing Laboratory. The ESF is unique in its design and experimental setup. Emerging contaminants of concern, such as endocrine-disrupting compounds, can be added precisely and simultaneously with the influent river water at the head of each experimental channel. Suspended solid and nutrient concentrations in the supplied river water can be manipulated as well. Very few operations have the level of dosing precision and failsafe design hardwired into their experimental setup. The ESF allows researchers to explore the effects of contaminants on traditional assessment endpoints, as well as to develop new and more effective measures (e.g., early warning biologically based monitors and reproductive endpoints) in a setting that can be scaled up to field conditions. Furthermore, linkages between pollutant loads and biotic endpoints can be identified—a critical step to the development of effective models in support of EPA water quality regulations, and implementation and monitoring plans. The ESF is the result of collaborative efforts from a number of sources. The experimental infrastructure was originally designed for the needs of a multinational corporation (the Procter and Gamble Company). Cross-laboratory collaboration takes advantage of expertise within several Office of Research and Development divisions, while biweekly meetings attended by project officers, technicians, and supporting contractors guide the research activities. In the first year of its operation, experiments conducted at the facility have resulted in a number of published abstracts and one proceedings paper delivered at national and international meetings. The chief beneficiaries, of course, are the environmental decision makers who will use ESF data in watershed models to quantitatively link known stressors in stream flow with the structure and function of stream ecosystems. For further information, contact Patricia Schultz, NRMRL Public Affairs Office, (513) 568-7966.
|
