An EPA panel tasked with reviewing the agency's draft report on water connectivity says the report is "thorough and technically accurate" in showing support for the proposed Waters of the U.S. rule.
The SAB review board agreed with two of the three major conclusions in the EPA's water connectivity draft, it said in an Oct. 17 report to EPA Administrator Gina McCarthy.
While the board said it agrees with EPA's scientific literature that suggests intermittent, ephemeral and perennial streams can impact downstream waters, and that tributaries are connected to downstream waters, it said the waters should be "considered in terms of a connectivity gradient."
The Board suggested also that the EPA revise the draft to improve clarity and make the document more useful to decision-makers.
The SAB disagreed with EPA's conclusion in the draft that suggested there was insufficient information to generalize about the connectivity of wetlands in unidirectional or non-floodplain settings.
In that case, the SAB said scientific literature supports a more definitive statement that reflects how "numerous functions of non-floodplain wetlands sustain the physical, chemical, and/or biological integrity of downstream waters, although the degree of connectivity can vary widely," the report said.
Finally, the board said EPA should consider expanding the brief overview on approaches to measure connectivity by providing examples of "dimensions of connectivity that could most appropriately be quantified."
EPA released the Waters of the U.S. proposal in March and has since extended the comment period twice. EPA said it does not plan to finalize the Waters of the U.S. rule until the SAB report has been fully reviewed.
Many farm groups oppose the rule on concerns that it expands the jurisdiction of the EPA in enforcing the Clean Water Act; environmental groups say it will improve water quality.