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Managing Mitigation Sites

Replanting photo
Replanting efforts at an active site
  • Adaptive Site Management
  • Adjusting Site Management
  • Site Closeout
  • Long-Term Site Maintenance

This page outlines the steps
WSDOT follows to manage wetland mitigation sites within the initial monitoring period. 

Adaptive Management Process

The purpose of WSDOT's adaptive management is to facilitate site development so that final performance standards and permit conditions are met in a timely manner.  The adaptive management process includes four steps relevant to site management after construction of wetland mitigation sites:

  1. Performance standards are developed to describe the desired condition.
  2. Management action is carried out so the site meets the performance standards.
  3. The response of the resource is monitored to determine if the performance standards have been met.
  4. Management is evaluated and adjusted if the performance standards are not achieved.

 The adaptive site management process is illustrated below.

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The Adaptive Site Management Process (Redrawn from Elzinga et al. 1998)

Monitoring and responsive site management are both integral to an effective adaptive management strategy. Without valid monitoring data, management actions may or may not result in improved conditions or compliance with regulatory permits. Timely site management decisions, based on valid monitoring data, result in increased efficiency and higher probabilities of success.

Manage the Mitigation Site (2)

Site managers rely on monitoring results to inform them of site performance. If the monitoring results show that a site is not on a trajectory to meet performance standards or permit requirements, the site manager decides whether different management activities might be more effective. 

Regions submit a funding request each biennium to fund wetland remediation. This estimate of future needs is typically based on past site performance. When authorized, these funds pay for personnel time, supplies (herbicide, plant material, and equipment rental), tool replacement, and charges for WSDOT vehicles. Designers and site managers may procure management activities either by contract or state force work.

There are several state force Restoration Crews available to coordinate with regions to conduct management activities on WSDOT mitigated wetland sites and stream restoration projects throughout the state. The Restoration Crews typically are requested to start to work after the site comes off contract, between years 1 and 3 after construction.

If the site is on a trajectory to meet performance standards and permit requirements, a site typically receives enough care from the Restoration Crew to keep it going in that direction.

If the site is not on a trajectory to meet either performance standards or permit requirements, landscape, biology, and monitoring staff discuss which management activities would be most effective. These tasks usually consist of weed control and re-planting native species, but the work may also include installing fencing, erecting informational signs, amending soils, or minor re-grading. 

Restoration Crew staff then coordinate with site managers to plan and budget costs for the work. The Restoration Crew updates the region manager when the work is complete, and the regions inform HQ Monitoring that the work has been done. 

Site managers use monitoring results and recommendations, best available science, their professional judgment, and available budget to decide which management activities to use at each mitigation site. Site managers may use contracts or state force to provide management activities on mitigation sites.  Implementing management actions includes:

  • Determining the most effective type of action
  • Determining the most effective time for the action
  • Reporting the action has occurred 
  • Evaluating effectiveness with follow-up site visits

Monitoring the Mitigation Site (3)

Information on how WSDOT monitors wetland mitigation sites is available at the following link: 

Adjusting Site Management (4)

In some cases, effective management strategies are difficult to find.  WSDOT convenes a multi-disciplinary team or consults with agencies and persists in managing wetland mitigation sites until final performance standards are met, or alternate compensation is found. 

In many cases, management action cannot create missing wetland area without excavation.  Wetlands are delineated within the first three years of monitoring so this potential problem can be addressed before plants are well established.

Adjusting the Performance Standards (1)

Sometimes a mitigation site develops in an unforeseen but acceptable direction.  Alternately, ideas about what is acceptable for a mitigation site may change.  In these cases, original performance standards may be inappropriate for the site.   Performance standards can be re-evaluated by the site manager and monitoring staff, and regulatory agencies can be requested to modify them.  This may mean modifying the permit.

Completing the Mitigation Site

After a wetland mitigation site has met all performance standards, and WSDOT has obtained regulatory concurrence, the site is transferred to the WSDOT Maintenance Division for long-term stewardship.  Lessons learned are incorporated into performance standards being written for new mitigation sites.