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TECHNOLOGY REQUIRED FOR ALTERNATIVE ANALYSES FOR A CHANGING ENVIRONMENT (TRACE) IN SUPPORT OF THE CLEAN WATER ACT
Impact/Purpose:
Develop, test, and refine models to evaluate sub-basins to determine whether local water quality problems due to excessive nutrient loading exist, and if so, to characterize them and determine their relationships to nutrient loading. Develop models to simulate overland flow and non-point source pollutant loads to track and assess nutrient loadings across watersheds and provide approaches for estimating nutrient budgets within sub-basins and for predicting changes in nutrient budgets in response to changes in watershed activities/land use/land cover. Demonstrate the application of the recommended approach/models for predicting changes in nutrient budgets in response to changes in proposed watershed activities/land use/land cover, resulting in specific recommendations for reducing the nutrient loads to a basin. For coherence, cooperation, and economics, these models will be housed in a unified, consistent, computational environment for environmental analyses that allows teaching (i.e., technology transfer) to multiple users (users concentrate on problem, not model input/output); that appeals to multi-disciplinary groups for distribution and use as a consistent assessment methodology (includes models, tools, modular design and facilitated updates of science/engineering); that includes resident visualization, animation tools, documentation and tutorials on-line, hooks to GIS and environmental databases; and is executable on UNIX, personal computers, and HPC resources.
Objective # 2.2 Conserve and enhance nation's waters: By 2005, conserve and enhance the ecological health of the nation's (state, interstate, and tribal) waters and aquatic ecosystems-rivers and streams, lakes, wetlands, estuaries, coastal areas, oceans, and groundwater-so that 75% of waters will support healthy aquatic communities.
Description:
Recent trends in current and evolving environmental regulatory strategies dictate that EPA will have to rely more heavily on predictive modeling technologies in carrying out the increasingly complex array of exposure and risk assessments necessary in developing scientifically defensible regulations (GPRA Goal 8.1.1). Under 303(d) of the CWA, each State must produce and provide EPA with a list of waters where water quality standards are not being attained, then prioritize the development of Total Maximum Daily Loads (TMDLs) for the waterbodies that will result in attainment of standards, and then develop and implement the TMDLs. In the event a State fails to develop the list or to develop TMDLs, EPA is obligated to do so. A TMDL is an estimate of the maximum pollutant loading from point and nonpoint sources that receiving waters can accept without exceeding water quality standards. There is a pressing need for multimedia, multistressor, multipathway assessments, from both human and ecological perspectives, over broad spatial and temporal scales for nutrients, sediments, pathogens, and toxics. These types of physicochemical stressors place a high priority on the development of broad new modeling tool packages. A modeling strategy is needed to: 1) demonstrate an approach to estimate basin-wide physicochemical loads as a function of point source controls and nonpoint source candidate BMP's; 2) demonstrate an approach to predict changes in physicochemical loading from changes in the watershed, including nutrient controls; and 3) demonstrate an approach to predict local water quality responses to physicochemical inputs. In response to this need, researchers at NERL-Athens have developed a series of models and problem-solving environments for characterizing and prioritizing physicochemical sources and loadings from individual sub-basins in larger watersheds, and ultimately, evaluating the impact of physicochemical loads on river systems, lakes and reservoirs and estuaries. The intention of the NERL-Athens program is to identify a suite of models capable of providing predictive capability for eutrophication caused by sediments and nutrients, then develop a similar predictive capability for pathogens and toxics. A concurrent objective of the NERL-Athens research is to develop and maintain a comprehensive technical support capability that directly links environmental TMDL exposure research activities and products for the EPA Office of Water and Regional Offices for use in the implementation of policy, regulatory development and remediation, and for enforcement.