Louisiana – Federal agencies are once again adjusting the reach of the Clean Water Act through a revised definition of “waters of the United States.” The Environmental Protection Agency and the Army Corps of Engineers published a supplemental proposal on Sept. 9 that could further narrow which streams and wetlands receive federal safeguards. ([1])The change carries outsized consequences for a state that holds roughly 40 percent of the nation’s coastal wetlands in the lower 48 states.
Why the Definition Matters Here
The phrase “waters of the United States” determines where Clean Water Act rules apply to pollution controls, dredging, and filling. Louisiana’s vast network of bayous, swamps, and marshes makes the state especially sensitive to any shift in that line. Seasonal flows and gradual transitions between land and water define much of the landscape, so small wording changes can affect large areas. These wetlands support a major seafood industry and provide critical habitat along the Mississippi Flyway. When federal coverage recedes, the practical effect reaches fisheries, water quality, and coastal resilience efforts that already cost the state billions.
Supreme Court Ruling Sets the Stage
The 2023 Sackett v. EPA decision limited the Clean Water Act’s scope to relatively permanent waters with a continuous surface connection to larger navigable waters. Agencies must now implement that ruling. The current proposal, however, explores options that could go further by emphasizing perennial flow, meaning water present essentially year-round. Louisiana officials and conservation groups note that many streams feeding the coast run strongly during wet months and diminish later. Treating only perennial waters as protected would exclude features that still deliver sediment and nutrients essential to downstream systems. The agencies have acknowledged they cannot fully quantify the acreage that might lose coverage.
Delta Landscape Challenges the New Tests
A second proposed tightening involves wetlands. The agencies are considering requirements tied to perennial surface water for establishing a continuous connection. In a deltaic environment, marshes and open water often blend across broad zones, with connections that vary by season yet remain functionally continuous under normal conditions. Requiring standing water every day of the year would exclude many marshes that clearly interact with adjacent bayous and bays. Commenters have urged the agencies to evaluate connections based on typical hydrology rather than an absolute daily standard.
State Authority Leaves Gaps
Louisiana maintains water-quality standards and a coastal permitting program inside designated zones. Outside those areas, however, the state has not assumed the federal Section 404 dredge-and-fill program. No comprehensive statewide substitute exists for the review process that once required avoidance, minimization, and mitigation before wetlands could be altered. When federal protection ends, many inland sites therefore lose oversight entirely. The proposal’s record should reflect this reality rather than assume automatic state replacement, according to submitted comments.
Clarity Needed Before Final Rule
The agencies have indicated that some exclusions under consideration reflect policy choices beyond the Sackett requirements. Distinguishing court-mandated limits from discretionary ones would help the public and future courts understand the basis for each line drawn. Louisiana Wildlife Federation and similar groups continue to track the docket as the agencies move toward a final decision.
