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LINKING GREAT WATERSHEDS AND RIVERS TO FORECAST THE IMPACT OF NUTRIENTS ON LARGE RECEIVING WATERS
Citation:
Rygwelski, K R., R G. Kreis, AND W. L. Richardson. LINKING GREAT WATERSHEDS AND RIVERS TO FORECAST THE IMPACT OF NUTRIENTS ON LARGE RECEIVING WATERS. Presented at USEPA Science Forum 2002: Meeting the Challenges, Washington, DC, May 1-2, 2002.
Description:
Assessment of our nation's waters, as per sections 305(b) and 303(d) of the Clean Water Act, indicates that approximately 40% are impacted by chemical and non-chemical stressors that impair designated beneficial uses and ecological habitat. Excess nutrients are often listed as a primary stressor. In order to protect and restore these impacted waters, the agency and states are moving towards an integrated multimedia ecosystem framework including monitoring, diagnosis of cause of impairment, establishing numeric standards and criteria, use of predictive models for forecasting environmental benefits, and development of Total Maximum Daily Loads (TMDLs) to achieve desired endpoints and restoration of water resources. Post remediation monitoring is conducted to measure the progress or effectiveness of actions taken.
The approach taken by the Mid-Continent Ecology Division (MED) to address the concern of the impact of nutrients to large receiving waters such as the Great Lakes is to use a mathematical modeling construct that integrates major media loading sources along with physical, chemical, and biological attributes of the system, and reflects ecosystem processes, relationships, rates and effects. A main focus is the relationship between lower food chain productivity and nutrients as it influences overall ecosystem production. Various multimedia models have been applied to several of the Great Lakes to gain an understanding of physical and biological nutrient cycling within the lake, and to determine nutrient loading rates to a Great Lake from its associated watershed, atmosphere, and sediments. Understanding these processes with the model framework allows the forecasting of lake conditions with respect to nutrient impact under various hypothetical or real remediation scenarios.
A TMDL set for controlling phosphorus loadings to achieve desired water quality standards in the lakes is frequently selected because this nutrient if often the limiting nutrient in eutrophication processes. Whole lake models as described above have been successfully applied to solve the problem of the "dead zone" in Lake Erie, and have recently been applied to Lake Michigan to gain an understanding of what phosphorus loading would permit achievement of the International Joint Commission's target concentration of 7 ug/L for phosphorus for that body of water. The phosphorus loading is estimated to be 5700 metric tonnes per year.
The recovery of Lake Erie, due to controls of phosphorus loadings from the watershed, has received national attention. Those target load reductions were the result of our modeling effort to understand the problem of oxygen depletion in that region. The Gulf of Mexico is displaying similar oxygen depletion zones and a modeling framework similar to that applied in the Great Lakes is being transferred to that system. MED's modeling team is working with the Gulf Ecology Division, the U.S. EPA Gulf of Mexico Program Office, the U.S. EPA Office of Water, the U.S. Army Corps of Engineers, the the U.S. EPA/National Exposure Research Laboratory's Ecosystems Research Division - Athens, GA to address the growing concern over the hypoxia issues in the Gulf of Mexico.
This abstract does not necessarily reflect EPA policy.
Assessment of our nation's waters, as per sections 305(b) and 303(d) of the Clean Water Act, indicates that approximately 40% are impacted by chemical and non-chemical stressors that impair designated beneficial uses and ecological habitat. Excess nutrients are often listed as a primary stressor. In order to protect and restore these impacted waters, the agency and states are moving towards an integrated multimedia ecosystem framework including monitoring, diagnosis of cause of impairment, establishing numeric standards and criteria, use of predictive models for forecasting environmental benefits, and development of Total Maximum Daily Loads (TMDLs) to achieve desired endpoints and restoration of water resources. Post remediation monitoring is conducted to measure the progress or effectiveness of actions taken.
The approach taken by the Mid-Continent Ecology Division(MED) to address the concern of the impact of nutrients to large receiving waters such as the Great Lakes is to use a mathematical modeling construct that integrates major media loading sources along with physical, chemical, and biological attributes of the system and reflects ecosystem processes, relationships, rates and effects. A main focus is the relationship between lower food chain productivity and nutrients as it influences overall ecosystem production. Various multimedia models have been applied to several of the Great Lakes to gain an understanding of physical and biological nutrient cycling within the lake, and to determine nutrient loading rates to a Great Lake from its associated watershed, atmosphere, and sediments. Understanding these processes with the model framework allows the forecasting of lake conditions with respect to nutrient impact under various hypothetical or real remediation scenarios.
A TMDL set for controlling phosphorus loadings to achieve desired water quality standards in the lakes is frequently selected because this nutrient if often the limiting nutrient in eutrophication processes. Whole lake models as described above have been successfully applied to solve the problem of the "dead zone" in Lake Erie, and have recently been applied to Lake Michigan to gain an understanding of what phosphorus loading would permit achievement of the International Joint Commission's target concentration of 7 ug/L for phosphorus for that body of water. The phosphorus loading is estimated to be 5700 metric tonnes per year.
The recovery of Lake Erie, due to controls of phosphorus loadings from the watershed, has received national attention. Those target load reductions wre the result of our modeling effort to understand the problem of oxygen depletion in that region. The Gulf of Mexico is displaying similar oxygen depletion zones and a modeling framework similar to that applied in the Great Lakes is being transferred to that system. MED's modeling team is working with the Gulf Ecology Division, the U.S. EPA Gulf of Mexico Program Office, the U.S. EPA Office of Water, the U.S. Army Corps of Engineers, the the U.S. EPA/National Exposure Research Laboratory's Ecosystems Research Division - Athens, GA to address the growing concern over the hyposia issues in the Gulf of Mexico.
This abstract does not necessarily reflect EPA policy.
Assessment of our nation's waters, as per sections 305(b) and 303(d) of the Clean Water Act, indicates that approximately 40% are impacted by chemical and non-chemical stressors that impair designated beneficial uses and ecological habitat. Excess nutrients are often listed as a primary stressor. In order to protect and restore these impacted waters, the agency and states are moving towards an integrated multimedia ecosystem framework including monitoring, diagnosis of cause of impairment, establishing numeric standards and criteria, use of predictive models for forecasting environmental benefits, and development of Total Maximum Daily Loads (TMDLs) to achieve desired endpoints and restoration of water resources. Post remediation monitoring is conducted to measure the progress or effectiveness of actions taken.
The approach taken by the Mid-Continent Ecology Division(MED) to address the concern of the impact of nutrients to large receiving waters such as the Great Lakes is to use a mathematical modeling construct that integrates major media loading sources along with physical, chemical, and biological attributes of the system and reflects ecosystem processes, relationships, rates and effects. A main focus is the relationship between lower food chain productivity and nutrients as it influences overall ecosystem production. Various multimedia models have been applied to several of the Great Lakes to gain an understanding of physical and biological nutrient cycling within the lake, and to determine nutrient loading rates to a Great Lake from its associated watershed, atmosphere, and sediments. Understanding these processes with the model framework allows the forecasting of lake conditions with respect to nutrient impact under various hypothetical or real remediation scenarios.
A TMDL set for controlling phosphorus loadings to achieve desired water quality standards in the lakes is frequently selected because this nutrient if often the limiting nutrient in eutrophication processes. Whole lake models as described above have been successfully applied to solve the problem of the "dead zone" in Lake Erie, and have recently been applied to Lake Michigan to gain an understanding of what phosphorus loading would permit achievement of the International Joint Commission's target concentration of 7 ug/L for phosphorus for that body of water. The phosphorus loading is estimated to be 5700 metric tonnes per year.
The recovery of Lake Erie, due to controls of phosphorus loadings from the watershed, has received national attention. Those target load reductions wre the result of our modeling effort to understand the problem of oxygen depletion in that region. The Gulf of Mexico is displaying similar oxygen depletion zones and a modeling framework similar to that applied in the Great Lakes is being transferred to that system. MED's modeling team is working with the Gulf Ecology Division, the U.S. EPA Gulf of Mexico Program Office, the U.S. EPA Office of Water, the U.S. Army Corps of Engineers, the the U.S. EPA/National Exposure Research Laboratory's Ecosystems Research Division - Athens, GA to address the growing concern over the hyposia issues in the Gulf of Mexico.
This abstract does not necessarily reflect EPA policy.