It’s All Connected: EPA Finally Determines that the Science Supports an Expansive Definition of Waters of the United States

On Thursday, EPA issued its final report on Connectivity of Streams & Wetlands to Downstream Waters:  A Review & Synthesis of the Scientific Evidence.  The Connectivity report is intended to support EPA’s rule clarifying the definition of waters of the United StatesCorps_Regulatory_Jurisdiction.  I know that groups on all sides will be providing their two cents, but of this I am sure enough to abandon my usual reluctance to speculate:  This report will be more than sufficient to insulate EPA’s final rule from judicial challenge.  If opponents of the rule want to defeat it, they’d better be working on those 60 votes in the Senate.

There’s a lot to the report, but the key conclusions can be summarized fairly simply:

  • The scientific literature unequivocally demonstrates that streams, individually or cumulatively, exert a strong influence on the integrity of downstream waters.
  • Wetlands and open waters in riparian areas and floodplains are physically, chemically, and biologically integrated with rivers via functions that improve downstream water quality.
  • Wetlands and open waters in non-floodplain landscape settings provide numerous functions that benefit downstream water integrity.
  • Watersheds are integrated at multiple spatial and temporal scales by flows of surface water and ground water, transport and transformation of physical and chemical materials, and movements of organisms.
  • The incremental effects of individual streams and wetlands are cumulative across entire watersheds ….  When considering the effect of an individual stream or wetland, all contributions and functions of that stream or wetland should be evaluated cumulatively.

I have frequently discussed the role EPA’s scientific support plays in judicial review of EPA regulations.  Suffice it to say that the level of peer review to which this report has been subjected will be enough for the Court of Appeals.

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