Mitigation proposals

Use the information on this page to plan and develop wetland mitigation proposals. During scoping and environmental review, consider compensatory mitigation options the order on this page:

  1. Use available Washington State Department of Transportation (WSDOT) mitigation credits
  2. Purchase third-party mitigation credits
  3. Develop a WSDOT compensatory mitigation site

Before using this page, see our Wetland mitigation page for things to consider prior to proposing compensatory mitigation.


1.Use available WSDOT mitigation credits

Use existing WSDOT mitigation credits if available. Determine availability of appropriate existing credits from an approved WSDOT mitigation bank, advance mitigation site (at least two years old), or from a nearby WSDOT compensatory mitigation site with excess credit. Then, write the credit use plan.

WSDOT Mitigation bank

Contact a region specialist or Gretchen Lux,, to determine if one of WSDOT’s three certified mitigation banks has credits suitable for your project:

Advance mitigation credit

Advance mitigation is permittee-responsible mitigation. Regulators approve advance mitigation plans when they authorize the site. Include details of how you will develop and use the advance mitigation credit.

Existing compensation site with excess credit

Excess mitigation is permittee-responsible mitigation. A compensatory mitigation site, developed as concurrent mitigation for a previous project, may have excess mitigation credit designated for future use. The mitigation plan and associated permit approvals must document that the compensation site has extra mitigation value to use for future projects, pending approval by regularly agencies.

Contact a region specialist to determine if one of WSDOT’s advance mitigation sites has credits or if excess mitigation credit is available from other WSDOT compensation sites.

Region specialists:

Northwest Region: Katina Kapantais

Olympic Region: Dave Molenaar

Southwest Region: Dan Corlett

South Central Region: Mark Norman

Eastern Region: Tammie Williams

North Central Region: Cindy Lysne

Write a wetland and stream mitigation bank, in-lieu fee, or advance mitigation credit use plan

See Washington State Department of Ecology's (Ecology) Using Credits from Wetland Mitigation Banks: Guidance to Applicants on Submittal Contents for Bank Use Plans (pdf 79 kb) for guidance on contents of the credit use plan.  

The credit use plan includes:

  • Project description
  • Avoidance and minimization measures
  • Aquatic resources impacts description (including acreage, function, and reference to Wetland and Stream Assessment Report)
  • Description of how the compensatory mitigation option was determined
  • Description of how the compensatory mitigation option provides appropriate compensation for impacted acreage and function of aquatic resources
  • Ledger showing debits and remaining credits


2. Purchase third-party mitigation credits

Purchasing mitigation credits from a certified non-WSDOT mitigation bank or in-lieu fee program may be a cost-effective option. Purchase of mitigation bank or in-lieu fee credits transfers all mitigation obligations to the program sponsor. Finalizing the credit purchase requires regulatory agency approval.

The project needs to occur within the mitigation bank or in-lieu fee’s service area. Refer to Ecology’s Wetland mitigation resources page for mitigation information and availability of third party mitigation bank or in-lieu fee programs. Ecology’s website includes a list of bank providers and maps showing the service area for each bank or in-lieu fee program.

The bank or in-lieu fee program must have sufficient available mitigation credits to compensate for project impacts. Contact the bank or in-lieu fee sponsor directly to determine available credits. See the bank or in-lieu fee sponsor website for details related to requirements for credit use.

Follow the Environmental Mitigation Credit Procurement Process (pdf 72 kb) to purchase credit from non-WSDOT entities to ensure compliance with applicable procurement laws and limit liability. Use the (docx 75 kb) to purchase environmental mitigation credits from a certified mitigation bank.

Write and submit a wetland and stream mitigation bank or in-lieu fee credit use plan.


3.Develop a WSDOT compensatory mitigation site

If WSDOT-established mitigation credits or suitable private non-WSDOT mitigation banks or in-lieu fee programs aren’t available, design an advance or concurrent compensatory mitigation site (compensation site). We hold responsibility for all aspects of compensatory mitigation including planning, permitting, implementation, performance, monitoring, and long-term management of the compensation site.

See Ecology’s Wetland mitigation banking page for guidance on developing a wetland mitigation bank.

See the 2012 Interagency Regulatory Guide: Advance Permittee-Responsible Mitigation page for guidance on developing an advance mitigation site.

You can construct a new mitigation site concurrently with the project.

Initiate your site selection process after you identify preliminary mitigation requirements, develop the site selection strategy, and identify the mitigation goals. Plan for early coordination with regulatory agencies when developing mitigation strategies for complex projects, advance mitigation, or other forms of mitigation.

Develop a site selection strategy that:

Identify site(s) that meet the anticipated mitigation need and comply with the site selection strategy. Proceed to data collection and project coordination to advance consideration of site(s).


Collect compensation site data

After identifying the compensation site and initiating the property acquisition, collect compensation site data for the wetland mitigation design and report. Conduct on-site vegetation, soil, and hydrological surveys. If wetlands already occur on the site, perform a wetland delineation, rating, classification, and functions assessment. Use methods and guidance provided on our Wetland and stream reconnaissance and assessment page.


Establish the mechanism for site protection


Develop a long-term management (LTM) plan

A Long-term management plan (LTM) describes how the compensatory mitigation site will be managed after performance standards have been achieved. The WSDOT region developing the project is responsible for development of the LTM plan.

The 2008 federal rule on Compensatory Mitigation for Losses of Aquatic Resources (Army Corps of Engineers [Corps] 33 CFR Parts 325 and 332, and Environmental Protection Agency 40 CFR Part 230 Section 332.4(c)) outlines the requirements for mitigation plans required for Department of Army permits authorizing impacts to aquatic resources.

Section 332.4(c)(11) describes the requirement for LTM plans:

“33 CFR Section 332.4(c)(11) Long-term management plan. A description of how the compensatory mitigation project will be managed after performance standards have been achieved to ensure the long-term sustainability of the resource, including long-term financing mechanisms and the party responsible for long-term management.”

Write a draft LTM to include in the mitigation plan which describes:

  • How the compensatory mitigation project will be managed after meeting performance standards to ensure the long-term sustainability of the resource.
  • What the financial mechanism is and who the party responsible for the LTM is- For WSDOT owned sites, WSDOT is the party responsible for LTM and providing financial support needed to support LTM of compensation sites through legislatively approved funds and budget requests.
  • The term and frequency of required management assessments - We expect inspections and/or assessments in Years 1, 4, 7, and 10 following the end of the compensation site compliance monitoring period as the minimum standard for reporting. More frequent inspections may be needed to protect the site integrity at sites with more immediate management issues that need to be addressed.
  • The triggers that require LTM reporting - Clearly identify why a LTM reporting is needed.
  • Reporting requirements of the LTM plan – Explain the duration and schedule of electronic submittal of LTM reporting, including the frequency and duration of any required LTM inspection or qualitative assessments.
  • General site management objectives to ensure protection of the site’s natural condition - Include objectives and tasks that address the following elements:
    • Objective 1: Physical Site Protection
      • Inspection of condition of fences and signage.
      • Inspection of conditions related to vandalism, trash, or other human caused damage to the site.
    • Objective 2: Protection for the natural condition of the site.
      • A summary of the results of required inspections and/or assessments.
      • A summary of adaptive management actions implemented in the time elapsed since the last LTM reporting period.
      • A summary of adaptive management actions planned in response to the results of the current LTM inspection and/or assessment.
  • Specific tasks to evaluate the objectives and any required inspection or LTM assessment.

An example of text for the LTM plan commitment in a mitigation plan:

“The compensation site is established and will be managed to ensure the long-term sustainability of the resource. A long-term management (LTM) plan will be developed for the compensation site. The objective of the plan is to ensure that the compensation site is managed to protect the natural condition of the established compensation site. The draft LTM plan will be submitted to the Corps of Engineers and Ecology for approval before the end of the compensation site compliance monitoring period. The draft LTM plan will specify the duration of the LTM period and the frequency of site inspection and qualitative assessments. LTM will be implemented for a minimum of 10 years and will start at the end of the compensation site compliance monitoring period. Results of the LTM site inspections and qualitative assessments will be submitted to the Corps of Engineers and Ecology as identified in approved LTM schedule or upon request of the agencies. The reports of LTM results will include summaries of management activities implemented as part of the ongoing LTM of the site.”

Submit draft LTM plans to the Corps and Ecology for approval prior to the end of the compensation site compliance monitoring period. Incorporate the LTM plan as an addendum to the approved mitigation plan or as a separate memorandum.


Develop the advance mitigation plan or conceptual mitigation plan

See the Corp’s Components of a mitigation plan for guidance on mitigation plan requirements. Headquarters technical specialists can help review your draft mitigation report.

Plan to coordinate with the regulatory agencies prior to permit application if your mitigation proposal doesn’t follow this guidance. Contact the region or headquarters mitigation specialist for assistance.

Refer to the existing conditions documented in the wetland and stream assessment report to determine area and type of impacts anticipated by the project. Identify appropriate types of compensatory mitigation (restoration, establishment, rehabilitation, enhancement, or preservation).

Use mitigation ratios to determine the appropriate amount of acreage or mitigation credit. See the Wetland Mitigation in Washington chapter on mitigation ratios. If the site design includes more wetland area than needed for project compensation at the site, propose that the excess be available for use by other projects. Document this intent in the mitigation plan. Clearly state the additional credit in the mitigation plan to be approved by the permitting agencies for later use.           

Establish performance criteria - Performance standards describe measurable attributes used to evaluate compensatory mitigation sites, such as plant density or percent cover. Regulators approve performance standards during the permitting process. Include them in the wetland and stream mitigation report. We typically monitor mitigation sites for up to 10 years to ensure the site meets performance standards. Reference our Writing performance standards for wetland mitigation (pdf 212kb) to identify meaningful and measurable standards for your project.

Write the wetland and stream mitigation report or advance mitigation plan after collecting all required compensation site data. An advance mitigation plan prepared by a wetland biologist includes:

  • Project description
  • Project avoidance and minimization of impacts to wetlands or other waters
  • Remaining unavoidable impacts
  • Compensatory mitigation approach
  • Mitigation site selection rationale
  • Baseline (pre-construction) conditions
  • Detailed mitigation plan - including grading plan, planting plans, and schematic plan showing mitigation types by area
  • Goals, objectives, and performance standards of the mitigation site
  • Monitoring and management plan - this does not affect the ongoing requirement for perpetual stewardship of the compensation site
  • Legal instrument for perpetual site protection
  • Long-term management plan

Submit the report as part of your application for a permit from the Corps and Ecology. See the Permits for work in wetlands & stream webpage for information on when and how to apply for permits. Wetland reports supporting the JARPA may include one or more wetland and stream assessment reports and a draft wetland and stream mitigation plan.

Finalize the draft wetland and stream mitigation plan in coordination with the permitting agencies. Don’t begin work on the final wetland and stream mitigation plan until the appropriate review agencies provide written conditional approval of the draft wetland and stream mitigation plan. Prepare the final mitigation design for contract during the design phase with development of the final plans, specifications, and estimates.


Initiate compensation site monitoring

Monitoring activities may need to begin before mitigation site construction starts. Follow the instructions on our Wetland monitoring page to start the compensation site monitoring process.


Construct the compensation site

Construct the site after designing and permitting the compensation site. See our Wetlands during construction page for information about how to limit impacts to wetlands during construction.

Contact the Wetland Program Manager, Tony Bush at for questions on compensation site development.