Recipient Organization
CAL POLYTECHNIC STATE UNIV
(N/A)
SAN LUIS OBISPO,CA 93407
Performing Department
Natural Resources Management and Environmental Sciences
Non Technical Summary
To aid in reducing the continued cycle of repetitive costs and losses from wildfires in the wildland-urban interface, we propose to (1) evaluate the efficacy of current regulations used to mitigate fire hazards by utilizing a novel spatial analysis technique in the footprints of the 2017 Thomas Fire, (2) examine what elements of current regulations potentially need modification, and (3) develop a cost/benefit analysis of various mitigation efforts that make communities more fire resilient.We will do so by utilizing existing spatial data, new data immediately collected by Cal Fire following the fire events, and fire behavior simulation software. Various inputs (e.g., roof type, housing density, structure distance from vegetation, etc.) will be evaluated against potential fire behavior during fire passage to evaluate which property factors most influenced home destruction (and saves). Factors deemed critical for building losses/saves will then be analyzed in a cost/benefit analysis to determine the costs needed to effectively mitigate wildfire damages.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Our proposed research seeks to bridge a knowledge gap so that policymakers and residents can more effectively mitigate wildland fire hazards and thereby reduce the cycle of repetitive fire costs and losses in California. To help elucidate the problems described above, we will employ a technical approach that is step-wise in nature and comprises 5 distinct objectives, including:OBJECTIVE 1: Summarize current WUI fire codes, land-use regulations and best practices from voluntary programsOBJECTIVE 2: Quantify the relative importance of various property features to WUI fire lossesOBJECTIVE 3: Identify shortcomings to current WUI fire codes, land-use regulations and voluntary programsOBJECTIVE 4: Develop a cost/benefit analysis to bring properties up to existing codes and regulationsOBJECTIVE 5: Disseminate findings
Project Methods
Work will mostly be at Cal Poly with travel to the study sites within the Thomas Fire footprint to ground-truth spatial data.Objective 1: Summarize current WUI fire codes, land-use regulations and best practices from voluntary programsReview, analyze and summarize current US regulations, codes and standards for mitigating fire hazards in the WUI. At a minimum, the current editions of the California Public Resources Code, the California Health & Safety Code, the California Fire Code, the California Building Code, International Wildland-Urban Interface Code Fire and relevant NFPA standards (e.g., 1, 1144) will be considered.The performance objectives associated with each requirement will be identified and the expected effectiveness of each requirement will be assessed. The expected output of this objective will be a report that identifies and summarizes the requirements and performance objectives for each building element that is addressed in the reviewed WUI regulations and standards.OBJECTIVE 2: Quantify the relative importance of various property features to WUI fire lossesBased on the results from Objective 1, we will define the specific property characteristics to include in the analysis for this objective. At an absolute minimum, elements in the most current WUI codes and standards for new construction in California will be included (including California Public Resources Codes 4290 and 4291 and California Building Code Chapter 7A).Pertinent data for the analysis will be obtained from Cal Fire and local jurisdictions and then analyzed via spatial analysis of structural losses (and survival) following the 2017 Thomas Fire. For each structure exposed to the Thomas Fire, spatial analysis per Dicus et al. (in review (a, b)) will be employed to quantify vegetative defensible space and other property characteristics that could lead to building ignition (e.g., proximity to outbuildings, etc.). (see full pdf for Figure 2)We will then perform a binary logistic regression to test which of the chosen structural and property characteristics influence the probability of structure loss during a wildfire event.The overall binary logistic model will be (see full pdf for formula)OBJECTIVE 3: Identify shortcomings to current WUI fire codes, land-use regulations and voluntary programsOnce Objective 2 is completed, potential shortcomings or gaps in WUI regulations or recommendations will be identified and assessed. Under Objective 3, the potential role of significant features identified in Objective 2 will be assessed in terms of actual fire performance. These features will also be addressed with pertinent fire officials engaged in this project to assess their concerns in light of the overall fire hazard associated with such properties.OBJECTIVE 4: Develop a cost/benefit analysis to bring structures up to existing codes and regulationsObjective 4 will use the results from Objective 2 to identify cost effective ways to reduce the risk of the current stock of WUI housing. Our analysis will provide guidance on the economic viability of retrofits using existing regulations and on how to set new and better regulations that take into account both effectiveness at reducing risk and cost of implementation. We will also develop a methodology for communities to prioritize risk mitigation actions across multiple structures in a neighborhood, taking into account risk spillovers and specific topographical features of the community that affect fire risk.In the context of wildfire risk management in the WUI, regulators attempt to develop regulations that reduce fire risk while not imposing costs on builders or homeowners that exceed the expected benefits of risk reduction. Our goal is to use economic analysis to systematically evaluate the current codes and propose new regulations designed to maximize expected benefits per dollar in expenditure.We divide this objective into three parts with increasing scope. First, we will conduct a cost/benefit analysis of existing regulations. Second, we will identify a cost-effective way to modify existing regulations to achieve the greatest risk reduction per dollar spent. Third, if we collect sufficient data in Objectives 1 and 2, we will identify a cost-effective way to reduce risk at the community level, accounting for risk spillovers between neighboring houses in the WUI.Cost/benefit Analysis of Existing RegulationsCost/benefit analysis (CBA) estimates the (present value of) benefits and costs associated with a proposed policy relative to the status quo. If the costs are greater than the benefits, then the analysis would recommend against implementing the policy. In order to evaluate existing codes and regulations related to wildfire risk, we will collect data on the costs associated with compliance with the California Fire Code and Public Resources Code, as identified in Objective 1. This cost data will be developed at the structure level, for a single structure to comply with regulations. Costs depend on the state of the existing structure, and so we will consider a variety of classes of structure when compiling cost data that differ in age, materials, and other important factors that affect risk.The next step in conducting a CBA of existing regulations is to monetize the expected benefits of the regulation. For this step, we will start with results of Objective 2 that quantified how various wildfire risk mitigation activities affect fire risk. To express these benefits in dollar terms, we will make assumptions (based on past fire outcomes) on the distribution of fire damages and then compute the expected value of fire damages with and without a regulation. For each class of structure, this will yield an estimate of the expected benefits of a regulation which can be directly compared to our cost data to determine if a retrofit is justified for that structure type.Cost Effective Reduction of Fire RiskWhile item (1) above will answer the question of whether existing regulations are economically justifiable, it does not address if and how the regulations can be improved. Just because the benefits of an existing regulation exceed the costs, it does not mean that the regulation is the best possible way of allocating resources to reduce fire risk. There may be other policies which would yield greater benefits or have lower costs or both. A cost-effective regulation is one which achieves the greatest reduction in risk per dollar in expenditures. With the data collected in Objective 2, we can estimate a cost-effective plan for reducing fire risk for homes in the WUI.Community-wide Reduction of Wildfire RiskIn practice, the reduction of wildfire risk is not best approached on a house-by-house basis but instead requires a community-wide approach. If a random sample of houses are chosen to meet the regulations established in item (2) above while many of their neighbors do not meet the regulations, it is likely that the effectiveness of the regulations will be substantially lower since houses that do not meet code and subsequently catch fire will facilitate the spread of the fire to nearby houses that do meet the code. Further, the benefits of fire risk mitigation depend on unique characteristics of each property including climate, slope, vegetation characteristics, and proximity to other houses.OBJECTIVE 5: Maximize dissemination to pertinent stakeholdersDue to the interdisciplinary nature of the project and of the research team, results will purposely be disseminated to diverse audiences and venues so as to maximize the research's impact. Specifics of anticipated dissemination is elucidated in the section that follows.EvaluationThe project will be evaluated on the success of the following milestonesCollection of all data; Analysis of data; Dissemination of results; Poster presentation; Oral presentation; M.S. Thesis; Refereed journal article; Science brief