4.3. Challenges and Opportunities in Translating Federal Policy into Quantitative Landscape Impacts
Overall, the development of federal wetland policy is underlain by an inherent tension between the recognized economic and environmental benefits of wetlands and the costs of regulation (Boyle et al., 2017). Although the preservation of a diverse suite of wetlands may ensure that a complete set of ecosystem services is maintained, we acknowledge that striving for policy that is clear, efficient, and interpretable is equally desirable (Mihelcic & Rains, 2020). Above all, regulations that contain definitions such as WOTUS often require interpretation by scientists and regulators, and consistent and clear guidelines can help to reduce uncertainty and make enforcement more efficient. While geospatial analyses such as this study can provide initial evaluations of policy outcomes, the translation of regulations into quantitative assessments of landscape impacts often requires more detailed and site-specific approaches. The implementation of Clean Water Act protections has long relied upon boots-on-the-ground assessments, and no amount of geospatial data can substitute for case-by-case field studies. Still, we assert that while regulatory determinations based on spatial data may be imperfect, broad-scale geospatial evaluations of wetland policy still provide considerable utility. Such approaches can be used to make a significant proportion of preliminary assessments of wetland jurisdiction, providing substantial benefits to regulators and landowners alike. While wetland-by-wetland assessments may be more accurate in determining the regulatory status of individual waters, geospatial analyses are still needed to capture complex and non-uniform regional patterns in protections across the landscape.
Despite the unique advantages provided by broad-scale assessments of wetland policy, we also acknowledge that such approaches are limited by imperfections inherent to all types of geospatial data. In wetland inventories, the extent of vulnerable non-floodplain wetlands is often insufficiently mapped due to their small size and dynamic state (Lane et al., 2022). Similarly, existing datasets representing the stream network at regional and broader scales are known to conservatively estimate river network extent (Elmore et al., 2013). Likewise, the location and extent of the stream network, which presently determines wetland protections under the CWA, expands and contracts seasonally and from year to year, making it difficult to map streams effectively (Godsey & Kirchner, 2014; Ward et al., 2018). Wetland locations and their connectivity to adjacent waters are also uncertain and prone to variations on a seasonal basis due to shifts in annual weather conditions and impacts from human activity. In aggregate, these uncertainties demonstrate that a combination of field evidence and professional judgment is still required to evaluate the regulatory status of a particular wetland. Regardless of these challenges, data-driven investigations such as the one presented here are a necessary step to ensure that we understand how the policies of today will impact the landscapes of the future (Mihelcic & Rains, 2020).
With yet another WOTUS revision on the horizon (USDOD and USEPA, 2021), it is a crucial time to consider the implications of existing science and to evaluate how changes to federal regulations will impact wetland protections and the environment at large. While the effects of recent WOTUS iterations have been assessed across several watersheds (Meyer & Robertson, 2019; Walsh & Ward, 2019), our understanding of the potential country-wide impacts of regulations such as the NWPR is worryingly deficient (Sullivan et al., 2020). Our findings of non-uniformity in the protection of wetlands across hydrologic regions, landscape positions, and wetland sizes indicate that the impacts of regulation are too complex to be extrapolated from studies at individual watersheds. Current and future wetland policy must be assessed at a national level to ensure that regulations uphold the CWA’s goal of maintaining the chemical, physical, and biological integrity of US waters (Federal Water Pollution Control Act Amendments, 1972). By investigating regulatory impacts at a continental scale, rather than generalizing from local-scale case studies, policymakers can ensure that wetlands receive equitable protections across the many diverse ecoregions of the US.