Isolated wetlands

We regulate waters of the state, including isolated wetlands, regardless of federal jurisdiction.

Isolated wetlands generally have no hydrologic connections to other aquatic resources. They are the most common type of wetlands regulated by state and local governments, but not by the federal government.

Even though isolated wetlands are not always protected under federal law, they often perform many of the same important environmental functions as other wetlands. They recharge streams and aquifers, store flood waters, filter pollutants from water, and provide habitat for a host of plants and animals (see Wetlands in Washington State- Volume 1, Chapter 5).

These wetlands remain protected under state and local laws and rules. Please work with our Federal Permit Coordinator when working with isolated wetlands. See more information below.

Court decisions exclude many
isolated wetlands from federal jurisdiction

A 2001 U.S. Supreme Court decision, known as the "SWANCC decision" (Solid Waste Agency of Northern Cook County v. United States Army Corps of Engineers et al., 531 U.S. 159), excluded many isolated wetlands from federal regulation.

The U.S. Supreme Court based this decision on a legal interpretation of "jurisdiction" under the federal Clean Water Act. The key factor was the language in the act that relates to navigable waters. The high court ruled that federal protection extends to wetlands located on or adjacent to navigable "waters of the U.S." or their tributary systems.

Wetlands with no link to interstate commerce are not federally regulated

Wetlands that do not meet this requirement, such as isolated wetlands with no link to interstate commerce, are not regulated as "waters of the United States" and therefore are not protected under the federal Clean Water Act.

Prior to this decision, the presence of migratory birds was considered enough to establish a link to interstate commerce. In SWANCC, however, the court ruled that the mere presence of migratory birds is insufficient for asserting CWA jurisdiction over isolated, intrastate, non-navigable water bodies. As a result, many isolated wetlands in Washington are not protected by federal law.

In general, the Corps considers isolated wetlands to be those of any size that are not adjacent* to or do not have a sufficient hydrologic connection to navigable waters. Corps policy regarding the definition and regulation of isolated wetlands is currently in flux, and future court or administrative decisions may further change how isolated wetlands are regulated by the federal government. (*See 33 CFR 328.3[c] for definition of adjacent.)

After the SWANCC decision, there was confusion about which wetlands were covered under the Clean Water Act. The U.S. Supreme Court provided little clarity in their 2006 “Rapanos decision” (Rapanos v. United States, 547 U.S. 715). Therefore in 2008, the Corps and EPA issued joint guidance describing how they determine which wetlands are covered under federal law based on the two decisions.

Recent developments

More recently, in a February 28, 2017, executive order, the Trump Administration directed the EPA to review the 2015 Clean Water Rule intended to clarify protection under the federal Clean Water Act for streams and wetlands. As part of this effort, the EPA will be reviewing the definition of navigable waters.

Corps determines if wetlands meet 'isolated' requirements 

Applicants and consultants must coordinate all projects potentially affecting isolated wetlands with the Army Corps of Engineers and receive a written jurisdictional determination. Consultants can provide information to state  agencies including Ecology but the final determination must be made by the Corps. See the Seattle Corps' regulatory county contacts.

Washington laws governing wetlands
not changed by federal courts

The state Water Pollution Control Act and associated regulations make no distinction between isolated and non-isolated wetlands. All "waters of the state" including isolated wetlands are covered by state law.

We continue to regulate isolated wetlands and apply the water quality standards prescribed by state law. Ecology’s process for regulating projects involving isolated wetlands is similar to the process used for federally-regulated wetlands.

Impacting an isolated wetland

When proposing to impact an isolated wetland, print and fill out the Isolated Wetlands Information Sheet. The information provided on the sheet will augment information provided in the Joint Aquatic Resources Permit Application (JARPA) and will expedite review of your project.

Submit the information to our Federal Permit Coordinator:

Washington Department of Ecology
Attention Federal Permit Coordinator
PO BOX 47600
Olympia WA 98504-7600

Phone: 360-407-6076