On April 21, 2020, the U.S. Environmental Protection Agency (“EPA”) and the U.S. Army Corps of Engineers (“USACE”) jointly published the final “Navigable Waters Protection Rule” (the “2020 Rule”) in the Federal Register. Effective June 22, 2020, the rule redefines the “Waters of the United States” that are subject to the federal Clean Water Act (“CWA”) in an attempt to clarify the definition of federally protected wetlands and reduce federal oversight over isolated and ephemeral water bodies. In a program highlighted by controversy for more than three decades, the 2020 Rule reintroduces regulatory uncertainty regarding the circumstances under which federal permits are required to disturb certain wetlands and ephemeral streams.
The 2020 Rule is the latest in a series of attempts by EPA and USACE to define which surface waters and wetlands are under federal jurisdiction. In 1986 and 1988, EPA and USACE issued the first regulations (the “1986/1988 Rule”) that defined that “Waters of the United States,” included wetlands. The 1986/1988 Rule used general terms that were subject to considerable dispute and litigation. After the U.S. Supreme Court issued decisions further defining and expanding the scope of protected wetlands, EPA and USACE issued the Clean Water Rule: Definition of Waters of the United States in 2015 (the “2015 Rule”) to clarify the Supreme Court’s definition and provide greater regulatory certainty. The 2015 Rule generally included wetlands that are adjacent to other wetlands and ephemeral streams as federally regulated waters.
The 2015 Rule was challenged in courts by some states, businesses and other organizations. Federal district courts ultimately issued orders staying the 2015 Rule in 28 states while the 1986/1988 Rule remained in effect throughout the other 22 states. In June 2017, the Trump administration’s EPA and USACE announced that they planned to repeal and replace the 2015 Rule that included wetlands adjacent to other wetlands and ephemeral streams within federal jurisdiction. EPA and USACE then published a final rule on October 22, 2019, that repealed the 2015 Rule, effective December 23, 2019. USACE and EPA published the 2020 Rule on April 21, 2020. The 1986/1988 Rule is currently in effect (in all states) until the new 2020 Rule becomes effective on June 22, 2020.
The 2020 Rule recognizes four categories of surface waters that are consistent with traditional notions of “Waters of the United States”: (1) territorial seas and traditional navigable waters (e.g., navigable rivers); (2) tributaries to territorial seas and traditional navigable waters; (3) lakes, ponds and certain impoundments with surface flow to traditional navigable waters; and (4) wetlands adjacent to other jurisdictional waters.
Under the 2020 Rule, perennial and intermittent streams and water bodies are subject to federal jurisdiction under the CWA. Perennial streams flow continuously throughout the year, where intermittent streams need not flow continuously throughout the year, but must flow more than just in response to a precipitation event. A significant difference between the 2015 Rule and the 2020 Rule is that the 2020 Rule excludes ephemeral surface waters, defined to mean streams that flow only after rainfall or snowfall. Ephemeral streams are estimated by environmental groups to account for up 18 percent of streams nationwide.
The 2020 Rule also limits federal jurisdiction over surface waters by excluding wetlands that are not adjacent to other jurisdictional waters. Under the 2015 Rule, if a wetland was adjacent to one or more other wetland areas, any of which had a surface water connection to jurisdictional waters, then all the wetlands in the chain of wetlands were jurisdictional waters. The 2020 Rule requires each wetland area to have its own direct connection to surface waters. Consequently, the 2020 Rule excludes from federal jurisdiction a significant percentage of wetlands that would have been covered as wetlands under the 2015 Rule, estimated to be as much as 51 percent of total wetlands according to some environmental groups.
It is apparent that the 2020 Rule opens up some of the issues relating to wetlands regulation that were tentatively resolved under the 2015 Rule. One of the reasons for including ephemeral wetlands in the 2015 Rule was that the distinction between ephemeral and intermittent wetlands is technically challenging and legally difficult to define. Similarly, the difference between a chain of interconnected wetlands with one connection to surface waters or many connections is not technically or legally clear. The result is that the 2020 Rule has reintroduced ambiguity into the definition of federally regulated wetlands that earlier rules attempted to resolve.
The 2020 Rule provides a definition of “Waters of the United States” that is narrower than the 2015 Rule, and therefore fewer waterbodies and wetlands should be subject to the jurisdiction of the CWA. As a consequence, companies may not have to obtain or comply with permits issued under the CWA because the projects are not impacting jurisdictional waters as defined under the 2020 Rule. However, if federal district courts issue state-by-state stays of the 2020 Rule rather than a nationwide stay, there could be discrepancies between states as to whether disturbance of isolated wetlands and ephemeral waterbodies requires federal permits. The potential for judicial decisions to rewrite the 2020 Rule means that regulated entities may be subject to an uncertain regulatory environment for years to come. One practical way to deal with this uncertainty is to assume that the most restrictive rules apply and to adopt a conservative approach to permitting and compliance that assumes the most expansive definition.
Another approach that companies may use to mitigate the challenges of this regulatory uncertainty is to obtain a “preliminary” or “approved” jurisdictional determination from the USACE. A preliminary jurisdictional determination is a non-binding determination from the USACE that “Waters of the United States” (including wetlands) may be present on a parcel of land and the approximate location(s) of such “Waters of the United States.” A preliminary jurisdictional determination is advisory and cannot be challenged in court. An approved jurisdictional determination, in contrast, is a binding, official USACE determination that jurisdictional “Waters of the United States” are either present or absent at a particular site. An approved jurisdictional determination may be challenged in court.
In the past, EPA and USACE have allowed companies to rely upon jurisdictional determinations that they received prior to the effective date of a new definition of “Waters of the United States” or prior to the stay of such a rule. If a jurisdictional determination is pending when a new rule comes into effect, an applicant for a jurisdictional determination may be able to ask the USACE to apply either rule. EPA and USACE have not yet issued guidance on jurisdictional determinations specific to the 2020 Rule but are likely to do so in the future. Based on past practices, filing applications for jurisdictional determinations as soon as feasible under the 2020 Rule may be the best way to keep permitting options open.
After decades of litigation regarding the definition of the “Waters of the United States,” more litigation is likely as states, environmental groups and other stakeholders challenge the 2020 Rule. Challengers to the new rule are likely to seek a nationwide stay on its effectiveness while they litigate the merits of the rule. Based on recent precedent limiting stays of the 2015 Rule to specific states, there is a strong possibility that the 2020 Rule – like the 2015 Rule – will be in effect in some states while it is enjoined in other states.
It is difficult to predict whether courts will uphold the 2020 Rule. The technical aspects of wetlands and their connection to surface waters are complex. There is little scientific basis for limiting CWA protections to wetlands that are directly adjacent to traditional navigable waters. There are few bright line tests that would facilitate the implementation of the 2020 Rule in the field. In addition, the history of judicial decisions on the topic tends to favor a more expansive definition of jurisdiction waters under the CWA than appears in the 2020 Rule. The 2020 Rule has therefore probably not simplified wetlands regulation, but has instead raised issues for further debate.
 85 Fed. Reg. 22,205 (Apr. 21, 2020).
 Isolated wetlands are those not directly connected to federally regulated surface waters. Ephemeral wetlands are those that appear infrequently, for example in response to rainfall events or snow melt.
 Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers, 531 U.S. 159 (2001); Rapanos v. United States, 547 U.S. 715 (2006).
 80 Fed. Reg. 37,053 (Aug. 28, 2015).
 In August 2015, the U.S. District Court for the District of North Dakota stayed the rule in thirteen states. North Dakota v. U.S. Environmental Protection Agency, No. 3:15-cv-00059 (D.N.D. Aug. 27, 2015). In October 2015, the U.S. Court of Appeals for the Sixth Circuit issued a nationwide stay of the rule. In re EPA, 803 F.3d 804 (6th Cir. 2015). However, in January 2018, the U.S. Supreme Court ruled that federal district courts, rather than federal appellate courts, had jurisdiction to hear the first challenges to the rule. Nat’l Ass’n of Mfrs. v. Dep’t of Def., 538 U.S. __, 138 S. Ct. 617, 625 (2018). As a result, in February 2018, the U.S. Court of Appeals or the Sixth Circuit lifted the nationwide stay of the Clean Water Rule.
 Georgia v. Pruitt, No. 2:15-cv-79 (D.Ga. June 8, 2018); Texas v. U.S. Environmental Protection Agency, No. 3:15-cv-00162 (Sept. 12, 2018); North Dakota v. U.S. Environmental Protection Agency, No. 3:15-cv-00059 (D.N.D. Sept. 18, 2018).
 84 Fed. Reg. 56,626 (Oct. 22, 2019). Some states and environmental groups are challenging the repeal of the Clean Water Rule. New York v. Wheeler, S.D.N.Y., No. 1:19-cv-11673.
 Ariel Wittenberg, Where EPA saw no data, Trout Unlimited crunched the numbers, Greenwire (Apr. 1, 2019).
 The 2020 rule defines “adjacent wetlands” as wetlands that abut a territorial sea or traditional navigable water, a tributary, or a lake, pond, or impoundment of a jurisdictional water; are inundated by flooding from a territorial sea or traditional navigable water, a tributary, or a lake, pond, or impoundment of a jurisdictional water in a typical year; are physically separated from a territorial sea or traditional navigable water, a tributary, or a lake, pond, or impoundment of a jurisdictional water only by a natural berm, bank, dune, or similar natural feature; or are physically separated from a territorial sea or traditional navigable water, a tributary, or a lake, pond, or impoundment of a jurisdictional water only by an artificial dike, barrier, or similar artificial structure so long as that structure allows for a direct hydrological surface connection to the territorial sea or traditional navigable water, tributary, or lake, pond, or impoundment of a jurisdictional water in a typical year, such as through a culvert, flood or tide gate, pump, or similar artificial feature.
 Under the 2015 Rule, “adjacent” meant within a certain distance to the jurisdictional water in relation to the ordinary high-water mark, floodplain, or high tide line of that water. Under the 2020 Rule, wetlands are “adjacent” if they: (1) abut (physically touch at least one point or side) a jurisdictional water, (2) are inundated by flooding from a jurisdictional water in a typical year, (3) are separated from a jurisdictional water by a natural berm, bank, or dune, or (4) are separated from jurisdictional waters by an artificial barrier and the structure allows for a direct hydrologic surface connection.
 Natural Resources Defense Council, NRDC and Partners Sue to Stop the Dirty Water Rule (Apr. 29, 2020), https://www.nrdc.org/experts/jon-devine/nrdc-and-partners-sue-stop-dirty-water-rule (last visited May 7, 2020); Waterkeeper Alliance, Navigable Water Protection Rule Guarantees Widespread Pollution of our Nation’s Waters (Feb. 13, 2020), https://waterkeeper.org/news/navigable-water-protection-rule-guarantees-widespread-pollution-of-our-nations-waters/.
 Judicial challenges against the rule were not resolved, so it is not clear whether the 2015 Rule would have been upheld by the courts.
 As evidence of this difficulty, the preamble to the 2020 Rule uses multiple examples in an effort to try to differentiate the terms, rather than using objective criteria or clear terminology.
 See US Army Corps of Engineers v. Hawkes Co., 136 S.Ct. 1807 (2016).
 See EPA, Technical Questions and Answers For Implementation of the Clean Water Rule, https://archive.epa.gov/epa/cleanwaterrule/technical-questions-and-answers-implementation-clean-water-rule.html. An approved jurisdictional determination is only valid for five years.
 See EPA, Technical Questions and Answers For Implementation of the Clean Water Rule, https://archive.epa.gov/epa/cleanwaterrule/technical-questions-and-answers-implementation-clean-water-rule.html.
 National Association of Manufacturers v. Department of Defense, 583 U.S. __, 138 S.Ct. 617, 624 (2018) (holding that challenges to the 2015 WOTUS Rule should be reviewed in district courts). If a challenge to the 2020 Rule relies on the Administrative Procedures Act, then the complainant has six years from the date that the claim arises to file the complaint.
 The 2015 Rule better aligns with the tests for federal jurisdiction set out in the concurrence by Justice Kennedy in the U.S. Supreme Court case Rapanos v. EPA where the Court issued a ruling on the definition of “Waters of the United States.” 547 U.S. 715 (2006).