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Decision Tool for Downstream Water Quality Protection

The Decision Tool for Downstream Water Quality Protection is an interactive interface designed to direct states, tribes, and territories to resources and methodologies when developing water quality criteria that provide for the attainment and maintenance of downstream water quality standards. A state-EPA workgroup developed this tool at the request of state partners.

Water quality criteria may be narrative or numeric. States, tribes, and territories have discretion in choosing their preferred approach, based on their specific circumstances. When considering whether a narrative or numeric downstream protection criterion is most appropriate, users are encouraged to read this Tool's companion document: Protection of Downstream Waters in Water Quality Standards: Frequently Asked Questions (PDF) (12 pp, 567 K, About PDF).

Selection and application of downstream approaches recommended by this tool do not ensure Agency approval or disapproval. EPA encourages early and frequent coordination between a state, tribe, or territory and their EPA Region to ensure the most streamlined water quality standard approval process.

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How to Use This Tool

Identify the pollutant of concern (Nutrients | Aquatic Life Toxic Pollutants | Human Health Toxic Pollutants) and answer the subsequent questions. The Decision Tool will display a record of your selections, and prompt the user with suggested resources at the end - and in some cases, along the way. In addition to the Decision Tool, EPA also provides the following two related resources for developing water quality standards for the attainment and maintenance of downstream water quality standards:

EPA also provides links on this page to other resources that may be useful in developing water quality criteria that protect downstream waters.

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Use the Decision Tool


Questions get put here...


Answers here...

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