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.