The Clean Water Act (CWA) was enacted to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters." The act, among other things, regulates the discharge of any pollutant from any point source to navigable waters and the discharge of dredged or fill material into navigable waters. Because the definition of "navigable waters" is "waters of the United States (WOTUS)", its applied definition is fundamental for projects that require CWA permits. The definition has changed often, however, and changed again last month.

How has the WOTUS definition changed since 2015?

In 2015, the Obama administration finalized its Clean Water Rule, which provided a new WOTUS definition that, it said, was intended in part to clarify which streams and wetlands fall under CWA protections. This rule covered many waterbodies that had not previously been considered a WOTUS, including certain wetlands and intermittent streams that are dry for part of the year. In 2019, the Trump administration rolled back the 2015 rule. Then, in 2020, the Trump administration implemented its replacement when it finalized the Navigable Waters Protection Rule (NWPR). The NWPR eliminated some of the 2015 rule's protections, including protections for wetlands and intermittent streams. The NWPR was viewed by many as more favorable to developers, farmers and industrial facilities.

Litigation ensued. On Aug. 30, the U.S. District Court for the District of Arizona issued an order vacating the NWPR. In its decision, the court stated that it vacated the NWPR because it contradicted feedback from EPA's Science Advisory Board and could cause serious environmental harms if used by a federal agency. The court further requested additional briefing on whether it should also vacate the Trump administration's 2019 rule that repealed the 2015 Clean Water Rule. So, for the time being, the pre-2015 WOTUS interpretations are in effect, but the court could rule that the 2015 Obama rule is now in effect.

The ruling's immediate impact

Since the ruling, EPA and the U.S. Army Corps of Engineers announced they will no longer apply the NWPR. The Biden administration was already working on repealing the NWPR and proposing a new WOTUS definition. Public comments for the new proposed definition closed on Sept. 3, though it is not clear now what impact the Arizona court's ruling and subsequent nationwide application will ultimately have on the administration's rulemaking. EPA and the U.S. Army Corps of Engineers are planning further opportunities for engagement.

In any event, during the rulemaking process, the agencies have said that they will now interpret WOTUS consistent with the pre-2015 regulatory regime, which includes the "significant nexus" test established by Justice Kennedy's plurality opinion in Rapanos v. United States.

This change in interpretation will significantly expand the reach of the CWA from the Trump-era definition, which could cause disruption for many stakeholders. For example, those with pending or planned wetlands approved jurisdictional determinations must now face a more restrictive regime. They should be prepared to draft or revise their applications accordingly.

We will continue to monitor all WOTUS developments. Our team will provide updates on opportunities to engage with the Biden administration as it moves toward the next evolution of the WOTUS rule and, perhaps, additional clarity, if not stability.

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