1.0 Introduction
Since the expansion of the Clean Water Act (CWA) in 1972, the federal protection of wetlands and rivers in the United States has been governed by the debated and fluid definition of the “waters of the United States” (WOTUS). Wetlands are crucial components of terrestrial landscapes, providing numerous benefits that include biological habitat, floodwater attenuation, biogeochemical processing, and sediment retention (Acreman & Holden, 2013; Capps et al., 2014; Cheng & Basu, 2017; Lane et al., 2018). Despite these widely recognized benefits, wetlands have been disregarded, destroyed, and filled for economic benefit over the past 200 years (e.g., Dahl, 1990; Davidson, 2014; Golden et al., 2019; Hey & Philippi, 1995; Van Meter & Basu, 2015), resulting in subsequent losses of ecosystem services (e.g., Zedler, 2003). Under the CWA, jurisdiction waters (WOTUS) require permits for pollutant discharges, dredging, or filling, while non-jurisdictional waters are afforded no such protections at the federal level. The extent of WOTUS has been ill-defined for more than 50 years, evolving through a series of legal cases and iterative rulemaking that have yielded an operational definition (Walsh & Ward, 2019; Walsh and Ward; In Review). Unlike laws that require legislative initiative, the definition of WOTUS is embedded in the rulemaking process of the executive branch, leaving operational definitions to be established by regulatory agencies (in this case, the USEPA and USACE). Through many high-profile judicial decisions and executive revisions, the extent of WOTUS has seen continual evolution and interpretation (Walsh & Ward, In Review).
The last decade has seen two redefinitions of WOTUS, resulting in significant changes to the federal protection of wetlands in the US. First, the 2015 Clean Water Rule (CWR) attempted to reconcile prior Supreme Court rulings (United States v. Riverside Bayview Homes , 1985; Solid Waste Agency of Northern Cook County v. USACE , 2001,Rapanos v. United States , 2006) into a clear-cut regulatory framework that was both consistent and easily interpretable (USDOD and USEPA, 2015). In addition to protecting intermittent and ephemeral river systems, the CWR classified adjacent waters and wetlands into jurisdictional categories using buffer distances from other protected waters. Leaving room for scientific interpretation, the CWR also codified the “significant nexus test”, mentioned in Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (2001) and reaffirmed in Justice Kennedy’s concurring opinion in Rapanos v. United States (2006). Under the significant nexus test, protections are extended to adjacent water and wetlands on a case-by-case basis if they “significantly affect the chemical, physical, and biological integrity” of adjacent navigable waters, taken alone or in combination with similarly situated waters (Rapanos v. United States , 2006). In response to these changes to the WOTUS definition, 31 states and a variety of other plaintiffs pursued legal action to oppose the enforcement of the CWR (e.g., Georgia v. Pruitt , 2018;North Dakota v. USEPA , 2015; Texas v. USEPA , 2018; USDOD and USEPA, 2019). After litigation and numerous preliminary injunctions, the CWR remained enforceable in only 22 US states, including New York (CRS, 2019). A new rulemaking process, intended to revise the CWR, was initiated via executive order in 2017 (Exec. Order No. 13778, 2017).
In 2019, the CWR was repealed and by April of 2020 replaced by the Navigable Waters Protection Rule (NWPR). To promote economic growth and development and to reduce regulatory uncertainty, the NWPR sought to redefine the legal term ‘navigable waters’ consistent with the opinion authored by Scalia et al. in Rapanos v. United States (2006). The NWPR restricted federal protections to waters that contribute flow to a traditionally navigable waterway or sea in a typical year (USDOD and USEPA, 2020). The updated rule also eliminated the significant nexus test, requiring wetlands to receive continuous surface flow from other jurisdictional waters to be considered jurisdictional. This redefinition of WOTUS under the NWPR was vacated by Pasqua Yaqui Tribe v. USEPA (2021 ). With the CWR repealed and NWPR struck down, federal wetland protections in the US have presently reverted to the regulations codified by the USEPA and USACE in 1986 (USDOD, 1986), though new rulemaking has been initiated (USDOD and USEPA, 2021).
Given the recency and fluidity of ongoing revisions to US federal water policy, few studies have assessed how the evolving definitions of WOTUS have altered the protection of wetlands (Sullivan et al., 2020). While a limited number of past studies have considered the protection of wetlands at the watershed scale (Walsh & Ward, 2019; Meyer & Robertson, 2019), additional work is still needed to characterize the complex implications of these changes to federal water policy, as the services provided by wetlands are non-uniform and vary considerably as a function of spatial location (Cohen et al., 2016; Lane et al., 2022; Marton et al., 2015) and size (Cheng & Basu, 2017; Ghermandi et al., 2010). This need is even more pressing given that the USEPA and USACE have indicated that a WOTUS revision will occur in the near future (USEPA, 2021). Thus, our objective in this study is to document how changes to the legal definition of WOTUS under the CWR and NWPR alter which wetlands are protected as a function of their landscape position and size. To achieve this objective, we use the wetland-dense state of New York (NYS) as a case study to demonstrate how changing regulatory language can yield patterns of protection that are biased against particular types of wetlands. Through regional analysis, we contribute to the evolving discourse assessing the implications of WOTUS definition revisions for wetland protections. We also provide additional discussion to contextualize the controversial nature of federal wetland protection and policy amongst numerous competing interests.