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Impaired Waters and TMDLs

EPA Issues November 15, 2010 Memorandum: Integrated Reporting and Listing Decisions Related to Ocean Acidification

The purpose of this memorandum is to provide information to assist the regions and states in preparing and reviewing integrated reports related to ocean acidification (OA) impacts under sections 303(d), 305(b) and 314 of the Clean Water Act (CWA). As part of a settlement agreement, EPA agreed to issue this memorandum by November 15, 2010, describing how EPA will proceed with regard to the issue of OA and the 303(d) program. This memorandum recognizes the seriousness of aquatic life impacts associated with OA and describes how states can move forward, where OA information exists, to address OA during the 303(d) 2012 listing cycle using the current 303(d) Integrated Reporting (IR) framework. At the same time, this memorandum also acknowledges and recognizes that in the case of OA, information is largely absent or limited at this point in time to support the listing of waters for OA in many States.

The memorandum reaffirms that states should list waters not meeting water quality standards, including marine pH water quality criteria, for their 303(d) 2012 lists, and should also solicit existing and readily available information on OA using the current 303(d) listing program framework. EPA will provide additional 303(d) guidance to the states when future OA research efforts provide the basis for improved monitoring and assessment methods, including approaches being developed under other federal efforts. This future OA guidance may be in the form of stand-alone OA IR guidance, or as part of EPA's routine, biennial IR update. EPA also encourages states to focus their efforts on OA-vulnerable waters (e.g., waters with coral reefs, marine fisheries, shellfish resources) that already are listed for other pollutants (e.g., nutrients) in order to promote ecological restoration.

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