Wetland tools & resources

We provide technical assistance and develop tools for local governments, consultants, and developers regarding the responsible management, regulation, and stewardship of wetlands in Washington.

Find out more about a wide range of wetlands topics such as how to calculate credits and debits for compensatory mitigation; resources for delineating and rating wetlands; and how climate change affects wetlands.


Best available science: A two-volume document on the science available on wetlands, their functions and management.

Calculating credits and debits for compensatory mitigation (Credit / Debit tool): A tool for calculating when a proposed wetland mitigation project adequately replaces the functions and values lost when wetlands are impacted.

Mapping resources: Find information about wetland-mapping efforts as well as links to available wetland map products and geospatial data.  

National coastal wetlands conservation grant program: We work in partnership with local and tribal governments, land trusts, and other state and federal agencies to apply for grants administered by the U.S. Fish & Wildlife Service to acquire, restore, and enhance wetlands in coastal states and U.S. territories.

Puget Sound Watershed characterization tool: Watershed characterization is a tool for including watershed conditions in the planning process. Watershed characterization information can help identify areas that are more appropriate for wetland restoration and mitigation. Links to other examples and guidance are provided.

Selecting wetland mitigation sites using a watershed approach: Recommendations on how to apply a watershed approach when selecting sites and in choosing between on-site and off-site mitigation (Western Washington version | Eastern Washington version).

Voluntary Stewardship Program: Provides electronic data and information, including links to wetland mapping resources, to support counties participating in the Washington's Voluntary Stewardship Program (VSP).

Wetland delineation resources: Wetland delineation establishes the existence (location) and physical limits (size) of a wetland for federal, state, and local regulation purposes.

Wetland program plan: In March 2015, we and an Interagency Work Group finalized the state's Wetland Program Plan. The plan is a strategic tool, developed and implemented by the state, to articulate what the state seeks to accomplish with the wetland program over time.

Wetland rating systems: Wetland ratings group wetlands into four categories based on their sensitivity to disturbance, their rarity, the ability to replace them, and the functions they provide. Some decisions that can be made based on the rating include the width of buffers needed to protect the wetland from adjacent development, the amount of mitigation needed to compensate for impacts to the wetland, and permitted uses in the wetland.

Wetlands & climate change: Wetlands are important for mitigating and adapting to the effects of climate change.