Local wetland regulations: Growth Management Act technical assistance

The Voluntary Stewardship Program (VSP) provides an alternative incentive-based approach for counties to address two fundamental goals of the state Growth Management Act:

Protect and enhance critical areas within the area where agricultural activities are conducted, while maintaining and improving the long-term viability of agriculture in the state of Washington and reducing the conversion of farmland to other uses - RCW 36.70A.700

We are interested in helping VSP watersheds achieve compliance with clean water requirements, and protect and restore critical areas. As members of the State-level VSP Technical Panel, we attend regular meetings and review periodic reports submitted by participating counties.

• VSP Contacts
• Find electronic data and mapping resources to support your VSP planning efforts

The publications listed below can be used by cities and counties to help develop regulations for protecting and managing wetlands:

• Washington State Wetland Rating System: The wetland rating system is designed to differentiate between wetlands based on their sensitivity to disturbance, their significance, their rarity, the ability to replace them, and the functions they provide. Wetlands are grouped into four categories used to determine regulatory criteria for avoidance, width of buffers, and compensatory mitigation ratios.
  • Eastern Washington version (October 2014, effective January 2015)
  • Western Washington version (October 2014, effective January 2015)
  • Guidance on 2014 Updates to Wetland Rating Systems and Buffers (recorded webinar). On June 3, 2014, Ecology wetland staff hosted a one-hour webinar regarding the 2014 updates to the wetland rating system. The webinar provides information about integrating the 2014 updates into a critical areas ordinance.​​
• Wetlands in Washington State - Volume 1: A Synthesis of the Science (March 2005): Under the Growth Management Act, local governments are required to use the best available science when reviewing and revising their wetland policies and regulations. We worked with the Washington Department of Fish and Wildlife to develop this comprehensive synthesis of the science regarding freshwater wetlands to assist local governments.
  • Update on Wetland Buffers: The State of the Science (October 2013): This update revisits the conclusions and key points concerning wetland buffers made in the 2005 synthesis.
• Wetlands in Washington State – Volume 2: Guidance for Protecting and Managing Wetlands (April 2005): This volume translates the science synthesized in Volume 1 into guidance on protecting and managing wetlands for local governments.
• Characterizing Wetland Buffers (September 2017): This manual provides procedures to assess compliance with wetland buffers that are required under regulations both at the state and local levels. It can be used by state agencies and local governments to characterize both the implementation and the effectiveness of their requirements for wetland buffers. The results can also be used to inform management decisions on policies and regulations regarding buffers.
• Interagency Guidance on Wetland Mitigation in Washington, Parts 1 and 2 (March 2006, Part 1 updated April 2021): This interagency guidance compiles existing information on wetland mitigation, including current agency policies. Part 1 provides an overview of the role the agencies play in regulating wetlands and explains some of the factors that go into permitting decisions regarding wetland mitigation. Part 2 contains technical information for developing wetland mitigation plans and proposals.