On Thursday, October 23, the Environmental Protection Agency’s (EPA) Science Advisory Board (SAB) released its 103-page review of the agency’s hydrology connectivity report.

The 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 review generally affirms the report’s scientific integrity, stating that the literature review is thorough and technically accurate.  While not an analysis of the proposed WOTUS rule or federal policy itself, the SAB did offer recommendations to improve the report’s clarity and consistency for policymakers.

“The [connectivity] Report is a science, not policy, document that was written to summarize the current understanding of connectivity or isolation of streams and wetlands relative to large water bodies such as rivers, lakes, estuaries, and oceans,” the Board writes.  “Given the policy context, however, the Report could be more useful to decision-makers if it brought more clarity to the interpretation of connectivity, especially with respect to approaches for quantifying connectivity.”

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 SAB’s review comes as a seven-month comment period on the WOTUS rule wraps up.  Final comments on the rule are due November 14, 2014.

About the Rule

The WOTUS rule attempts to provide greater clarity to the definition of “waters of the United States” in the CWA after several Supreme Court cases have cast confusion over the phrase.  The EPA and Corps propose making all tributaries, as well as adjacent waters, jurisdictional under the Act.

While the conservation community broadly supports the rulemaking as a necessary step to maintaining the integrity of the nation’s waters, some sectors of the business and agriculture communities have called the rule a burdensome and costly regulatory overreach.

NSAC has followed WOTUS from the beginning and will submit formal comments to the agencies to make sure sustainable agriculture has a voice in the rulemaking process.

Click here to read NSAC’s Q&A on the WOTUS rule.

For even more information on the proposed rule, visit the EPA’s WOTUS website.