Skip to main content
Open Access Publications from the University of California

Road Ecology Center

Recent Work bannerUC Davis

Washington State Department of Transportation contaminated sites and Endangered Species Act risk reduction


Washington State’s regulatory criteria for prioritizing contaminated site cleanups are primarily based on human health risk; risks to Endangered Species Act (ESA)-listed aquatic species are not directly considered. Under existing state regulation, sites considered low priority for cleanup may pose considerable risk to ESA threatened and/or listed fish species. The objective of this project was to create an internal assessment tool for the Washington State Department of Transportation (WSDOT) to assess and prioritize contaminated site risks to ESA listed aquatic species. A three-tiered evaluation process was developed to determine relative potential for contaminated sites to affect ESA-listed fish species. Based on results of an initial screening, a determination was made regarding potential impact to listed fish and/or their habitat. Sites posing potential risk were then ranked in order of priority for remedial action. Tier I evaluated sites for their relative distance to the documented presence of listed fish and their critical habitat; Tier II evaluated the status of hazardous material releases and the potential for contaminants to impact surface water and/or critical habitat areas; Tier III assigned a quantitative site scoring to rank sites based on risk to ESA-listed fish species. Scores range between 0 and 100 with higher values assigned for higher risk sites. A total of 103 sites were evaluated. Of these, 41 were considered to pose potential risk and were assigned quantitative scores. For the 16 sites receiving scores of 75 or above, WSDOT will seek funding to conduct early cleanups. For remaining sites, WSDOT will further assess whether there is sufficient risk to warrant cleanup activities. Because this model has proved useful, WSDOT will continue to use it to measure the agency’s ESA risk as it relates to contaminated sites and to support expenditures for conducting further site characterization and cleanup work. Though there remains uncertainty regarding relative toxicity of individual contaminant levels on fish species, this model should prove useful to the regulated community as well as to regulatory agencies in reaching defensible cleanup decisions as they relate to ESA-listed fish.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View