Wetlands - Mitigation site inventory

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Mitigation site inventory measures

Performance analysis

2022

WSDOT adds 6.97 acres of riparian and oak woodland compensatory mitigation sites in 2022

WSDOT began monitoring two new riparian and oak woodland compensatory mitigation sites on 6.97 acres in 2022. Compensatory mitigation sites compensate for the effects of transportation projects and help offset climate change impacts. WSDOT is actively monitoring 94 sites (959 acres) until the sites meet initial permit requirements.

WSDOT's statewide inventory of 323 total compensatory mitigation sites includes:

  • 73 sites in the 10-year monitoring period;
  • 8 sites past the initial 10-year monitoring period that have not yet met all permit requirements;
  • 7 sites being evaluated by the U.S. Army Corps of Engineers' and Washington State Department of Ecology for completion of their permit requirements;
  • 6 mitigation banks; and
  • 229 sites in long-term stewardship that have met their permit requirements.

2021

WSDOT adds 32.7 acres of wetland and stream mitigation sites in 2021

WSDOT began monitoring nine new compensatory wetland and stream mitigation sites on 32.7 acres in 2021. Mitigation sites compensate for the effects of transportation projects and help offset climate change impacts. WSDOT is actively monitoring 107 sites (1,043 acres) until the sites meet initial permit requirements.

WSDOT's statewide inventory of the total 321 compensation sites includes:

  • 79 compensation sites in the 10-year monitoring period;
  • 3 sites past the initial 10-year monitoring period that have not yet met all permit requirements;
  • 19 sites being evaluated by the U.S. Army Corps of Engineers' and Washington State Department of Ecology for completion of their permit requirements;
  • 6 compensatory mitigation banks; and
  • 214 sites in long-term stewardship that have met their permit requirements.

2020

WSDOT adds 14.39 acres of wetland and stream mitigation sites in 2020

WSDOT began monitoring six new compensatory mitigation sites on 14.39 acres in 2020. Mitigation sites compensate for the effects of transportation projects and help offset climate change impacts. WSDOT is actively monitoring 112 sites (1,062 acres) until the sites meet initial permit requirements. The agency started to issue monitoring reports on compensation sites in 1988 and has since transferred 200 of the total 312 sites (584 of the total 1,646 acres) to long-term stewardship where WSDOT and partners—including local government agencies—will continue to monitor the sites after initial permit requirements are met.

WSDOT's statewide inventory of the total 312 mitigation sites includes:

  • 78 compensation sites currently in the 10-year monitoring period;
  • 5 sites past the initial 10-year monitoring period that have not yet met all permit requirements;
  • 23 sites being evaluated by the U.S. Army Corps of Engineers and Washington State Department of Ecology for completion of their permit requirements;
  • 6 compensatory mitigation banks; and
  • 200 sites in long-term stewardship that have met their permit requirements

2019

WSDOT adds eight acres of wetland and stream mitigation sites in 2019

WSDOT began monitoring six new compensatory mitigation sites on eight acres in 2019, bringing the total to 306 compensation sites on 1,631 acres. The agency started to issue monitoring reports on compensation sites in 1988 and has since transferred 176 sites to long-term stewardship with WSDOT partners—including local government agencies—which monitor the sites after initial permit requirements are met. WSDOT will continue to monitor the remaining 130 sites on 1,208 acres until initial permit requirements are met.

WSDOT's statewide inventory of 306 mitigation sites includes:

  • 84 compensation sites currently in the 10-year monitoring period;
  • 1 site past the initial 10-year monitoring period that has not yet met all permit requirements;
  • 39 sites being evaluated by the U.S. Army Corps of Engineers and Washington State Department of Ecology for completion of their permit requirements;
  • 6 compensatory mitigation banks; and
  • 176 sites in long-term stewardship that have met their permit requirements.

2018

WSDOT adds 17 acres of wetland and stream mitigation sites in 2018

WSDOT began monitoring nine new wetland and stream mitigation sites on 17 acres in 2018, bringing the statewide total to 300 wetland and stream mitigation sites on 1,623 acres. The agency started issuing monitoring reports on mitigation sites in 1988 and has since transferred 173 sites to long-term stewardship with WSDOT partners—including local government agencies—which monitor the sites after initial permit requirements are met. WSDOT will continue to monitor the remaining 127 sites until initial permit requirements are met.

WSDOT's statewide inventory of 300 mitigation sites includes:

  • 88 wetland and stream mitigation sites currently in the 10-year monitoring period;
  • 3 sites that are beyond the 10-year monitoring period but have not yet met all permit requirements;
  • 30 sites being evaluated by the U.S. Army Corps of Engineers (Corps) and Washington State Department of Ecology (Ecology) for completion of their permit requirements;
  • 173 sites in long-term stewardship that have met their permit requirements; and
  • 6 mitigation banks.

How mitigation banks work for WSDOT

Guidance from the Environmental Protection Agency and the U.S. Army Corps of Engineers' on compensatory mitigation for construction projects recommends mitigation banking. Mitigation banking is like a "savings account" for WSDOT's future capital projects and mitigation needs. These banks create credits based on the number of acres and their value. These credits can be withdrawn from the account (or used) by projects as compensation for unavoidable wetland impacts within the bank's specified service area.

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