Specific Objectives of the Project:

• Assess water utilities wildfire risk, with a specific focus on rural and agricultural communities;
• Establish an association between water utilities’ vulnerability level to wildfires with water utilities’ and communities’ characteristics; and
• Estimate short- and long-run effects of wildfires on households’ bottled water and water purifying products purchases, with a specific focus on rural and agricultural communities.

Summary of Results:
The project is completed for the first and second objectives, and a paper is submitted to the Journal of Water Resources Management. For the third objective, data is collected and merged/cleaned, but we are still working on refining the results. We do not have a working paper for this objective yet. Summary of the results from the first and second objectives are listed below.

Wildfires have occurred more frequently and are more devastating in California, and quantifying their impact on water utilities, which potentially may lead to water availability and water quality threats, is essential. This is especially important for water utilities whose characteristics are susceptible to wildfires. Due to the unpredictable nature of wildfires, drinking-water utilities face a considerable challenge in developing plans and strategies for managing floods and treating polluted water. Information and tools are needed to help water storage and treatment managers better prepare for the impacts of wildfires.

Our study quantifies these impacts by measuring the effects of wildfire on each water utility service area, based on the exposure frequency and the extent of acres burned by wildfires that occurred in each water utility service area, and by calculating the severity of the wildfire. Our quantitative models take into account the nature of the censoring and selection biases on wildfire data and show an association between water utility characteristics and the level of vulnerability to wildfire risks.

As a result of the cross-sectional estimation of the OLS, Tobit, and Heckman models, we found that wildfire severity increased in areas of (1) government-owned utilities vs. private-owned utilities; (2) utilities relying on surface water vs. those relying on groundwater; (3) utilities relying on local water sources vs. those relying on purchased water; (4) utilities located in Southern vs. Northern California; (5) utilities located on the coast vs. inland California; and (6) utilities in highly populated areas vs. non-populated areas.

Our findings can potentially inform public land managers and water utilities by identifying which water utilities are most vulnerable to wildfires based on their characteristics. They also show the potential characteristics of water utilities that are highly likely to experience changes in potential water availability and quality degradation immediately following a wildfire. Our research reveals that utilities more vulnerable to wildfires will require more strategic management decisions. It also suggests that the countermeasures on wildfires should be different depending on the characteristics the utility has. For example, based on an assessment of wildfire severity, by identifying the utilities and their locations of greatest risk, the relevant institutes could set costs associated with wildfire damage and mitigation activities.

Wildfire management and reducing the risk of wildfires are problems not only for the U.S. Forest Service or other public land management utilities but many other entities, such as water utilities. To help solve this pressing issue, partnerships are needed to help identify landscapes with hazardous vegetation and implement effective land management strategies by federal, state, local municipalities, communities, and nongovernment utilities. From this point of view, our study findings may help inform public land managers about possible shared stewardship partnerships with water utilities to leverage resources and expertise to reduce hazardous vegetation on shared landscapes, thus reducing wildfire risk.