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USEPA'S APPROACH FOR ESTABLISHING NATIONAL NUTRIENT CRITERIA FOR ESTUARIES AND COASTAL WATER
Citation:
Dettmann, E H., M. N. Liebman, D A. Flemer, AND J S. Latimer. USEPA'S APPROACH FOR ESTABLISHING NATIONAL NUTRIENT CRITERIA FOR ESTUARIES AND COASTAL WATER. Presented at New England Estuarine Research Society, Salem, MA, May 31- June 3, 2001.
Description:
The USEP A is developing procedures for establishing nutrient criteria to aid states and tribes in setting nutrient standards for the nation's water bodies and coastal waters. Criteria are being developed separately by water body type (e.g. lakes and reservoirs, rivers and streams, wetlands, estuaries and coastal marine waters). To account for regional differences caused by local environmental conditions, criteria for freshwater systems are being developed separately for each distinct ecoregion. Technical guidance manuals have been published for lakes and reservoirs and for rivers and streams, and associated criteria documents are being developed for aquatic systems in each ecoregion. For lakes and streams, nutrient criteria are largely based upon reference conditions determined from comparative analysis of similar water bodies in the same ecoregion. This presentation focuses on the process for developing nutrient criteria for estuaries and coastal marine waters, systems that are highly individual in their susceptibility to nutrient enrichment. The technical guidance manual for estuaries and coastal marine waters is currently in peer review. Approaches for developing nutrient criteria in estuaries include analysis of past loading rates and concentrations, identification of reference-quality estuaries that can be used as the reference condition for other similar estuaries, and use of data for minimally impacted freshwater tributaries to estimate reference nutrient loading rates from the entire watershed. Because of the more variable and complex hydrodynamics of estuaries, the proposed procedures for these systems focus more strongly on estuary-by-estuary analyses, rather than on comparative analyses of reference conditions as do those for freshwater systems. Modeling is also an important component of the process being developed for estuaries. The USEPA anticipates that nutrient criteria for estuaries and coastal waters will evolve with time, and the Office of Research and Development is undertaking a long-term research program to further develop loading-response relationships. The USEPA's Office of Science and Technology anticipates completing nutrient criteria on an estuarine/coastal province basis within the next 3-5 years.