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Linking trading ratio with TMDL (total maximum daily load) allocation matrix and uncertainty analysis
1CH2M HILL, Chantilly, VA 20151, USA. harry.zhang@ch2m.com
Summary
Watershed pollutant trading faces challenges with uncertain tradeoffs between point and nonpoint sources. This study introduces an equivalent trading ratio (ETR) method, linking uncertainty analysis to determine fair trading ratios for water quality goals.
Area of Science:
- Environmental Science
- Water Resource Management
- Environmental Engineering
Background:
- Watershed-based pollutant trading is an innovative approach for Total Maximum Daily Load (TMDL) allocation.
- Scientific uncertainty in source tradeoffs makes setting trading ratios contentious, hindering pollutant trading programs.
- Existing studies often lack explicit methods for determining trading ratios, with uncertainty analysis rarely integrated.
Purpose of the Study:
- To present a practical methodology for estimating an "equivalent trading ratio" (ETR).
- To link uncertainty analysis with trading ratio determination within the TMDL allocation process.
- To provide a preliminary evaluation of tradeoffs between point and nonpoint source control strategies for water quality improvement.
Main Methods:
- Development of a methodology to estimate the Equivalent Trading Ratio (ETR).
- Integration of uncertainty analysis into the determination of trading ratios.
- Evaluation of tradeoffs between point and nonpoint source control strategies.
Main Results:
- The ETR provides a preliminary assessment of tradeoffs between different control strategies.
- A higher proportion of nonpoint source (NPS) load reduction generally correlates with greater uncertainty, necessitating a higher trading ratio.
- The methodology quantifies trading ratios, enhancing the scientific basis for watershed-based pollutant trading.
Conclusions:
- The proposed ETR methodology offers a practical approach to address uncertainty in pollutant trading.
- Rigorous quantification of trading ratios improves the scientific foundation and public acceptance of trading programs.
- Informed decision-making in watershed-based pollutant trading is enhanced through explicit uncertainty analysis and ETR determination.
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