Approved by the Energy, Environment, and Water Policy Committee on August 26, 2025 
Approved by the Public Policy and Practice Committee on August 27, 2025
Adopted by the Board of Direction on October 7, 2025

Policy

The American Society of Civil Engineers (ASCE) supports the U.S. Army Corps of Engineers (USACE) and the Environmental Protection Agency (EPA) in maintaining regulations that protect national wetlands and enforcing clearly defined wetlands subject to jurisdictions under Section 404 of the Clean Water Act (CWA). ASCE supports regulatory policy that:

  • Maintains federal jurisdiction over all interstate and navigable waters, their tributaries, and all adjacent wetlands.
  • Clarifies state jurisdiction over isolated, non-navigable intrastate waters and adjacent wetlands, (including vernal pools, playas, and prairie potholes), that is based on environmental and wildlife regulations promulgated by the Department of the Interior or the EPA.
  • Improves consistency in wetlands regulations with clear, science-based, and nationally consistent definitions of wetlands, including seasonal and isolated wetlands, to ensure uniform application of regulations and protection measures across jurisdictions.
  • Strengthens wetlands protection in infrastructure development that requires infrastructure projects to assess and minimize impacts on wetlands, incorporating wetland buffers, permeable surfaces, and other sustainable water management practices in project design.
  • Enhances wetland monitoring and restoration efforts through the use of advanced monitoring technologies and data-driven assessments to track wetland conditions, evaluate restoration effectiveness, and ensure compliance with regulatory standards.
  • Establishes a definition of wetlands under the CWA which includes:
    o Wetlands adjacent to navigable and interstate waters, including floodplains and coastal marshes.
    o Wetlands associated with perennial intermittent, and ephemeral tributaries, including headwaters.
    o Wetlands with demonstrated groundwater or subsurface hydrologic connections to Waters of the United States. 
    o Constructed or restored wetlands providing significant ecological or hydrological functions.

Issue

Despite their importance, wetlands continue to face degradation and loss due to urban development, agricultural expansion, and inconsistent regulatory protections. In recent years, regulatory uncertainty has increased following significant legal and administrative changes affecting the jurisdictional scope of the Clean Water Act (CWA).

The U.S. Supreme Court’s May 2023 decision in Sackett v. Environmental Protection Agency significantly narrowed the definition of “waters of the United States” (WOTUS), limiting federal jurisdiction to wetlands with a continuous surface connection to navigable waters. This ruling excluded many seasonal and isolated wetlands, such as vernal pools, playas, and prairie potholes, from federal oversight, raising concerns about increased wetland loss and reduced water quality protections. In response, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers issued a revised WOTUS rule in August 2023, formally incorporating the Court’s decision and further clarified federal regulatory authority over certain wetlands.

The shifting regulatory framework has led to uncertainty over which level of government has jurisdiction over specific water bodies and adjacent wetlands. This lack of clarity has created challenges for infrastructure planning, conservation efforts, and compliance with wetland protection laws. Intermittent and ephemeral streams, which contribute to hydrological stability and ecological health, also require clear regulatory guidance under Section 303 of the CWA to ensure proper oversight and protection.

The loss of federal protections for many wetlands places a greater burden on state and local governments to regulate and manage these ecosystems effectively. However, state-level protections vary widely, resulting in inconsistent conservation outcomes and potential gaps in wetland oversight. Without uniform, science-based definitions and regulatory consistency, many wetlands remain vulnerable to degradation, affecting flood control, water quality, and habitat integrity.

Furthermore, the lack of standardized monitoring and restoration efforts limits the ability to track wetland health, evaluate restoration effectiveness, and enforce compliance. Advancing data-driven assessments and modern monitoring technologies will be essential to ensure the long-term sustainability of wetland ecosystems.

Clear, science-based regulatory frameworks that define federal, state, and local jurisdiction over wetlands, improve consistency in wetland regulations, and integrate monitoring and restoration technologies are necessary to balance environmental protection with economic development.

Rationale

Wetlands are vital natural resources that provide water filtration, flood control, groundwater recharge, erosion prevention, and habitat for diverse plant and animal species. Their conservation is essential to maintaining water quality, protecting communities from extreme weather, and supporting biodiversity. However, wetlands face increasing pressure from urban expansion, agriculture, and inconsistent regulatory protections, leading to widespread degradation and loss.

The U.S. Supreme Court’s 2023 decision in Sackett v. Environmental Protection Agency significantly redefined federal jurisdiction over wetlands, restricting protections to those with a continuous surface connection to navigable waters. This ruling, along with the subsequent EPA and U.S. Army Corps of Engineers regulatory adjustments, has removed federal protections for many seasonal and isolated wetlands. As a result, wetland oversight now depends more heavily on state and local governments, creating regulatory inconsistencies that could threaten wetland conservation efforts.

Clear and consistent wetland regulations are necessary to balance environmental protection with responsible infrastructure development. A well-defined division of federal, state, and local jurisdiction will ensure that wetlands receive appropriate protection while providing regulatory certainty for project planning. The role of intermittent and ephemeral streams, as well as seasonal and isolated wetlands (such as vernal pools, playas, and prairie potholes), must be clarified to ensure their continued contribution to water management, habitat preservation, and flood mitigation. 

Infrastructure development must integrate wetland conservation strategies, including the use of wetland buffers, permeable surfaces, and sustainable water management practices. Additionally, enhanced monitoring and restoration efforts through advanced technologies and data-driven assessments will improve the effectiveness of wetland protection and ensure compliance with regulatory standards. 

By promoting scientific, consistent, and jurisdictionally clear wetland regulations, ASCE supports a balanced approach that safeguards wetland ecosystems while allowing for responsible land use and infrastructure development. 

ASCE Policy Statement 378 
First Approved in 1991