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United States Department of Agriculture

Agricultural Research Service

Title: Mathematical Simulation Tools for Developing Dissolved Oxygen Tmdls

Authors
item Vellidis, G - UNIV. OF GEORGIA
item Barnes, P - KANSAS STATE UNIV.
item Bosch, David
item Cathey, A - BUCK ENG., ATLANTA, GA

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2006
Publication Date: August 28, 2006
Citation: Vellidis, G., Barnes, P., Bosch, D.D., Cathey, A.M. 2006. Mathematical Simulation Tools for Developing Dissolved Oxygen TMDLs. Transactions of the American Society of Agricultural and Biological Engineers. 49(4):1003-1002.

Interpretive Summary: The amount of dissolved oxygen (DO) in water is one of the most commonly used indicators of river and stream health. Under extended hypoxic (low DO) or anoxic (no DO) conditions, most higher forms of life are driven off or die. In many regions of the USA, low DO is a common fresh water impairment. States, Territories and Tribes of the USA are required by federal law to develop Total Maximum Daily Loads (TMDLs) for waters not meeting established DO standards. Regulators and other professionals are increasingly relying on mathematical simulation models to develop these TMDLs. This paper provides a guide to mathematical simulation models available for developing DO TMDLs. Two case studies, one from Georgia and one from Kansas, are presented. The case studies indicate that DO models can be a useful tool for better understanding natural watersheds and for making decisions related to improving in-stream DO. The results illustrate the importance of proper model parameterization, calibration, and validation, and most importantly a proper understanding of the model by the user. This work provides a consistent and comprehensive evaluation of DO models to assist TMDL developers in selecting appropriate models for their application.

Technical Abstract: The amount of dissolved oxygen (DO) in water is one of the most commonly used indicators of river and stream health. In most fresh water systems, aquatic fauna become stressed as DO drops below 4 or 5 mg L-1. Under extended hypoxic (low DO) or anoxic (no DO) conditions, most higher forms of life are driven off or die. Consequently, most water quality standards require a daily DO concentration average of 5 mg L-1 and no less than 4 mg L-1 at all times for waters supporting warm water species of fish. In many regions of the USA, low DO is a common fresh water impairment. States, Territories and Tribes of the USA are required by federal law to develop Total Maximum Daily Loads (TMDLs) for waters not meeting established DO standards. Regulators and other professionals are increasingly relying on mathematical simulation models to develop these TMDLs. The goal of this paper is to provide a guide to mathematical simulation models available for developing DO TMDLs. For this work, a model is defined as easily available software which can be used to simulate DO dynamics in flowing fresh water (riverine) systems. Four commonly used DO simulation models (QUAL2E, HSPF, SWAT, and WASP) are described in detail. Two case studies, one from Georgia and one from Kansas, are presented. The case studies indicate that DO models can be a useful tool for better understanding natural watersheds and for making decisions related to improving in-stream DO. Many of the models currently available for TMDL DO analysis continue to be enhanced. The models continue to become more sophisticated and more representative of the natural environment. The results illustrate the importance of proper model parameterization, calibration, and validation, and most importantly a proper understanding of the model by the user. This work provides a consistent and comprehensive evaluation of DO models to assist TMDL developers in selecting appropriate models for their application.

Last Modified: 8/22/2014
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