Wetlands - Mitigation site acreage

2022

WSDOT actively monitors 94 compensatory mitigation sites in 2022

From 2003 through 2022, the number of WSDOT-monitored compensatory mitigation sites increased from 59 to 94 (59%) and total acreage increased from 360 to 959 (166%). These increases are primarily a result of construction projects funded by the 2003 Nickel and the 2005 Transportation Partnership Account revenue packages.

To ensure these sites meet permit requirements, WSDOT monitors hydrology, vegetation, and wildlife as they develop—typically for 10 years—before transferring them to agency partners for long-term stewardship.

WSDOT strives to meet completion requirements for compensatory mitigation sites

There were 13 compensatory mitigation sites that were at the end of their monitoring period in 2022. WSDOT completed monitoring work at all the sites (which included a total of 115 acres); WSDOT will request concurrence from the regulatory agencies to ensure these sites can be transferred to long-term monitoring with WSDOT's partners.

Mitigation options help WSDOT and the environment

WSDOT's six mitigation bank sites did not earn or debit (use) any credits in 2022.

Five of WSDOT's six mitigation banks have earned the maximum amount of credit possible. In 2022, there were no projects in the banks' service areas that required credit for wetland mitigation. Mitigation banks preserve, enhance, restore, or create wetlands to offset impacts on existing wetlands from future construction projects. WSDOT mitigation banks efficiently meet future project needs and maximize environmental benefits. They do this by restoring ecological functions—like creating amphibian habitat and providing storage areas for floodwater—prior to any damage that project activity would cause to those ecological functions. The agency's mitigation banks save time and money by consolidating work efforts and banking credits for future projects.

How mitigation banks work for WSDOT

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 These credits can be withdrawn from the account (debited) by projects as compensation for unavoidable wetland impacts within the bank's specified service area.

2021

WSDOT actively monitors 107 mitigation sites in 2021

From 2002 through 2021, the number of WSDOT-monitored mitigation sites increased from 53 to 107 (102%) and total acreage increased from 174 to 1,043 (499%). These increases are primarily a result of construction projects funded by the 2003 Nickel, the 2005 Transportation Partnership Account and Connecting Washington revenue packages.

To ensure these sites meet permit requirements, WSDOT monitors hydrology, vegetation, and wildlife as they develop—typically for 10 years—before transferring them to agency partners for long-term stewardship.

WSDOT strives to meet completion requirements for mitigation sites

In 2021, seven compensatory mitigation sites were at the end of the monitoring period. WSDOT completed monitoring work at six of these sites (11.48 acres) and will seek approval from regulatory agencies to transfer the sites to long-term monitoring with WSDOT's partners. One site (0.30 acres) will require an iterative process and additional monitoring to determine if the desired condition is achieved.

2020

WSDOT actively monitors 112 mitigation sites in 2020

From 2001 through 2020, the number of WSDOT-monitored mitigation sites increased from 54 to 112 (107%) and total acreage increased from 213 to 1,062 (399%). These increases are primarily a result of construction projects funded by the 2003 Nickel and the 2005 Transportation Partnership Account revenue packages.

To ensure these sites meet permit requirements, WSDOT monitors hydrology, vegetation, and wildlife as they develop—typically for 10 years—before transferring them to agency partners for long-term stewardship.

WSDOT strives to meet completion requirements for mitigation sites

In 2020, WSDOT requested to close out 10 mitigation sites that were at the end of the monitoring period. Regulatory agencies determined that WSDOT completed monitoring work at seven mitigation sites (10.11 acres); these will be transferred to long-term monitoring with WSDOT's partners. The other three sites (5.40 acres) will require adaptive management and additional monitoring.

Mitigation options help WSDOT and the environment

WSDOT's six mitigation bank sites earned 0.55 credits and debited 3.98 credits to transportation projects in 2020.

Mitigation banks preserve, enhance, restore, or create wetlands to offset impacts on existing wetlands from future construction projects. WSDOT mitigation banks efficiently meet future project needs and maximize environmental benefits. They do this by restoring ecological functions—like creating amphibian habitat and providing storage areas for floodwater—prior to any damage that project activity would cause to those ecological functions. The agency's mitigation banks save time and money by consolidating work efforts and banking credits for future projects.

2019

WSDOT actively monitors 130 mitigation sites in 2019

From 2001 through 2019, the number of WSDOT-monitored compensation sites increased by 141% (54 to 130) and total acreage increased by 467% (213 to 1,208). These increases are primarily a result of construction projects funded by the 2003 Nickel and the 2005 Transportation Partnership Account revenue packages. To ensure these sites meet permit requirements, WSDOT monitors hydrology, vegetation, and wildlife as they develop—typically for 10 years— before transferring them to agency partners for long-term stewardship.

WSDOT strives to meet completion requirements for mitigation sites

WSDOT completed monitoring work at six compensation sites (64.4 acres) where permit requirements were met by the end of the monitoring period. WSDOT will request concurrence from regulating agencies that these be closed out in 2020.

WSDOT mitigation sites provide benefits such as water quality improvement, wildlife and pollinator habitat, and storage areas for floodwater.

Two compensation sites were past the initial monitoring period in 2019, but not yet transferred to long-term stewardship with WSDOT partners. One site (5.76 acres) has not yet met all final-year permit requirements, but was replanted in 2018 and again in 2019. It will be monitored again in 2020. The other site (0.45 acres) met permits requirements in 2019.

Wetland mitigation siteshelp reduce climate impacts

WSDOT wetland mitigation sites not only compensate for the effects of transportation projects, but can also mitigate climate change impacts.

Wetland mitigation sites protect infrastructure assets by storing floodwater and improve the quality of water by filtering stormwater. They also absorb and store excess carbon from the atmosphere (for more information, visit http://bit.ly/WSDOTclimate). WSDOT's wetland mitigation sites in or near estuaries buffer coastlines from extreme weather events.

Mitigation options help WSDOT and the environment

WSDOT's six mitigation bank sites earned 2.86 credits and debited 0.12 credits to transportation projects in 2019.

Mitigation banks preserve, enhance, restore, or create wetlands to offset impacts on existing wetlands from future construction projects. WSDOT mitigation banks efficiently meet future project needs and maximize environmental benefits. They do this by replacing ecological functions—like creating amphibian habitat and providing a storage area for floodwater—prior to any damage that transportation projects would cause to those ecological functions. The agency's mitigation banks save time and money by consolidating work efforts and banking credits for future projects.

2018

WSDOT actively monitors 127 mitigation sites in 2018

From 2001 through 2018, the number of WSDOT-monitored wetland and stream mitigation sites increased by 135% (54 to 127) and total acreage monitored increased by 468% (213 to 1,209). These increases are primarily a result of construction projects funded by the 2003 Nickel and the 2005 Transportation Partnership Account revenue packages. To ensure these sites meet permit requirements, WSDOT monitors hydrology, vegetation and wildlife as they develop—typically for 10 years—before transferring them to long-term stewardship with agency partners.

WSDOT strives to meet completion requirements for mitigation sites

WSDOT completed monitoring work at two mitigation sites (0.65 acres) where permit requirements were met by the end of the monitoring period.

WSDOT mitigation sites provide benefits such as water quality improvement, wildlife and pollinator habitat, and storage areas for floodwater.

Three mitigation sites were past their initial monitoring period in 2018. One site (5.76 acres) had not yet met all final-year permit requirements, but was replanted in 2018; WSDOT will continue to monitor this site until it meets performance standards. The other two (1.25 acres) met all permit requirements in 2018, and WSDOT will request that these sites be transferred to long-term management.

Wetland mitigation sites help reduce climate impacts

WSDOT wetland mitigation sites not only compensate for the impacts of transportation projects, but can also mitigate climate change impacts.

Wetland mitigation sites protect infrastructure assets by storing flood water and improve the quality of water by filtering stormwater. They also absorb and store excess carbon from the atmosphere. WSDOT's wetland mitigation sites in or near estuaries buffer coastlines from extreme weather events.

Mitigation options help WSDOT and the environment

WSDOT's six mitigation banks earned 7.42 credits and debited 0.89 credits to transportation projects in 2018. Mitigation banks preserve, enhance, restore or create wetlands to offset impacts on existing wetlands from future construction projects. WSDOT mitigation banks efficiently meet future project needs and maximize environmental benefits by replacing ecological functions—like creating amphibian habitat and providing a storage area for floodwater—prior to any damage that project activity would cause to those ecological functions. The agency's mitigation banks save time and money by consolidating work efforts and banking credits for future projects.