The “Transportation Project Mitigation Cost Screening Matrix” or “screening tool” is a tool that helps transportation planners identify proposed projects that may benefit from the application of watershed-based mitigation. Specifically, the screening tool would help WSDOT to:
- Identify projects that may benefit economically or have improved project delivery by using watershed-based mitigation.
- Identify projects that should have minimal environmental impacts or where mitigation should be relatively uncomplicated and inexpensive.
- Give early warning about projects that may be financially, logistically, or administratively difficult to mitigate.
- Allow timely development of other mitigation options such as low impact development and watershed-based mitigation.
- Identify areas where multiple transportation projects could benefit from watershed characterization.
The screening tool analyzes readily-available data on urbanization, floodplain areas, soil types, topography, wetlands, hazardous materials, parks and other cultural resources. Projects that encounter these features commonly have the highest environmental mitigation costs, especially for stormwater treatment and wetlands replacement. The tool generates a “mitigation risk index” or “MRI” consisting of a single score that estimates the percentage of land area within the project limits that will likely experience logistical difficulties or elevated costs for in right-of-way environmental mitigation.
For more information, please contact:
Ed Molash
(360) 705-7496 or
Molashe@wsdot.wa.gov