EPA's science board backs WOTUS

Connectivity report offers recommendations to improve the waters of the U.S. rule.

The Environmental Protection Agency’s (EPA) water rule passed a crucial test, gaining the approval of the agency’s internal review board.  

EPA is proposing to expand its jurisdiction to include small rivers and streams that flow into larger sources of water.  The anticipated report, Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific Evidence, reviews and synthesizes hydrology literature and is largely the scientific basis for the EPA and Army Corps of Engineers’ proposed rule to define “Waters of the United States” under the Clean Water Act (CWA).

The panel reviewed the EPA’s draft report on the connectivity of waterways around the country. “Relatively low levels of connectivity can be meaningful in terms of impacts on the chemical, physical, and biological integrity of downstream waters,” the advisory board wrote.

Environmental groups say the rule is needed to protect the nation’s water sources from contamination, but those opposed say it would be unduly expensive to comply with, particularly for farmers.

The EPA proposed the rule in April. The advisory board said it is “grounded in current science,” but offered several recommendations to clarify the rule and improve transparency.

In its review, the SAB recommends that the EPA modify its connectivity report to:

  • Provide a greater emphasis on biological and groundwater-mediated connectivity between streams, wetlands and downstream waters, as well more analysis of human alterations to the hydrological landscape;
  • Include more discussion—perhaps represented through case studies—of connectivity on a gradient and understanding connectivity from a watershed or landscape perspective;
  • Increase the consistency and clarity of terminology used throughout the report, particularly related to terms like “floodplain wetlands;” and
  • Provide further analysis and more specificity regarding cumulative or aggregate effects of similarly situated waters (i.e., groups of headwater tributaries).

The public has until November 14 to comment on the proposed rule.

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