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Water: Total Maximum Daily Loads (303d)

Clarification of the use of Biological Data and Information in the 2002 Integrated Water Quality Monitoring and Assessment Report Guidance

MEMORANDUM

DATE: March 26, 2002
SUBJECT: Clarification of the use of Biological Data and Information in the 2002 Integrated Water Quality Monitoring and Assessment Report Guidance
FROM: Robert H. Wayland III, Director /s/
Office of Wetlands, Oceans and Watersheds
TO: EPA Regional Water Management Directors
EPA Regional Science and Technology Directors
State, Territory and Authorized Tribe Water Quality Program Directors


This memorandum modifies the 2002 Integrated Water Quality Monitoring and Assessment Report Guidance to provide clarity and promote consistency in the manner in which states use biological data and information in developing their 2002 submissions. Specifically, EPA has removed the following paragraph from the Guidance...

"If a state or territory determines that an AU does not meet a use based on biological information and the cause of the impairment is unknown, the AU may be listed in Category 3. If a state or territory lists the AU in Category 3, EPA strongly recommends that the state or territory schedule additional monitoring to expeditiously determine the cause of the impairment."

EPA believed that this paragraph could have been interpreted to be inconsistent with the intent of the Clean Water Act (CWA) because it could have led to the placement of a formally defined impaired water into Category 3. When existing and readily available data and information (biological, chemical or physical) are sufficient to determine that a pollutant has caused, is suspected of causing, or is projected to cause the impairment, the AU should be listed in Category 5. (When biological data and information indicates that the impairment is not caused by a pollutant, the AU may be placed in Category 4C.) Only when the state determines that the existing data and information (biological, chemical or physical) are insufficient to support an attainment determination, can an AU be listed in Category 3.


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