Clarifying which U.S. waters are within EPA’s jurisdiction
“Based on the literature, the Office of Research and Development was able to assess the types of connections between the tributaries and adjacent waters and the chemical, physical, and biological integrity of downstream traditional navigable waters, interstate waters, and the territorial seas.”
But identifying the nexus alone is not enough to satisfy the court’s concern. “as Justice Kennedy found…a mere hydrologic connection may not suffice in all cases to establish CWA jurisdiction and there needs to be ‘some measure of the significance (emphasis added) of the connection for downstream water quality.’”
In the proposed rule the agencies write, “The data and conclusions in the Report concerning the strength of the relevant connections (emphasis added) and effects of certain types of waters on downstream waters provide a foundation for the agencies’ determinations that certain waters have effects on the chemical, physical, and biological integrity of traditional navigable waters, interstate waters, or the territorial seas that are ‘significant’ (emphasis added) and thus constitute a significant nexus (emphasis added).”
The proposed rule says, “the Report concludes that the scientific literature clearly demonstrates that streams, regardless of their size or how frequently they flow, strongly influence how downstream waters function. Streams supply most of the water in rivers, transport sediment and organic matter, provide habitat for many species, and take up or change nutrients that could otherwise impair downstream waters.
“The Report also concludes that wetlands and open waters in floodplains of streams and rivers and in riparian areas (transition areas between terrestrial and aquatic ecosystems) have a strong influence on downstream waters. Such waters act as the most effective buffer to protect downstream waters from nonpoint source pollution (such as nitrogen and phosphorus) [it should be noted that much of the potential pollution caused by farming is nonpoint source pollution], provide habitat for breeding fish and aquatic insects that also live in streams, and retain floodwaters, sediment, nutrients, and contaminants that could otherwise negatively impact the condition or function of downstream waters.
“Regarding wetlands and open waters located outside of floodplains and riparian areas, the Report finds that they provide many benefits to rivers, lakes, and other downstream waters. If the wetland or open water has a surface or shallow subsurface water connection to the river network, it affects the condition of downstream waters.