Water Scarcity and Wildfire Risk

I. Abstract

Over the past few years, the state of California has experienced a surge in wildfire occurrences and the expansion of Fire Hazard Severity Zone (FHSZ) markings, raising the question of what preventive measures can be taken to reduce risk, prevent damage, and protect land.

Although wildfires are intrinsically linked to water demand and supply, this correlation is overlooked in existing research. This report examines California's current policy landscape on water rights and reviews available data on water demand and supply, arguing that a stronger emphasis on water trading could indirectly address wildfire prevalence by ensuring the equitable distribution of rights and allocations across the state.

II. Introduction

We classify the state of California into three regions: Southern, Central, and Northern. The southwestern United States has long been susceptible to wildfires. Before large scale Western development, Indigenous peoples in California had long practiced controlled burns to reduce the risk of uncontrolled wildfires. However, climate change has increased the frequency and intensity of wildfires. The area burnt by wildfires between 1996 and 2021 is five times larger than that burnt between 1971 and 1995.

Human pressures on natural water systems are amplifying the impacts of droughts, increasing the dryness that leads to wildfires. Central California's primary groundwater basin is critically overdrafted, despite having the highest water demand among the three regions. Southern California has the smallest groundwater basin volume as well as the smallest reservoir volume, matched by consistently low rainfall. It is not a coincidence that this region has the greatest number of FHSZs.

III. Existing Water Rights Allocations and Land Protection Legislation

The Water Commission Act, passed in California in 1914, established the State Water Resources Control Board, which manages and oversees water rights allocations and handles conflicts, applications for, and transfers of those allocations between parties. There are three major systems of water rights allocation in California: pre-1914 rights, riparian rights, and appropriative rights.

Riparian rights are those that allow landowners to use water from sources that flow through or next to their property. The most widely recognized form in California is appropriative rights, defined on a first-come, first-served basis and requiring beneficial use. The current system's underfunding creates significant inefficiencies in the Water Board's monitoring and reporting, which lead to further inefficiencies in allocations during droughts or periods of scarcity.

The Sustainable Groundwater Management Act (SGMA), enacted in 2014, requires local groundwater sustainability agencies to bring basins into balance by the 2040s. Wildfire risk is not taken into account when determining these allocations.

IV. Recommendations

Existing water rights legislation and allocation policy have been first-come, first-served, tied to water overallocation, and restricted by land ownership. These limitations contribute to continued unsustainable water use, legal ambiguity, and regional inequity.

Water markets offer a solution to these limitations. Treating water allocations as market transactions addresses concerns about regional equity by allowing areas in greater need, such as wildfire-prone areas, to receive additional water when demand exceeds the originally allocated amount. California already uses Dry Year Option Trades; we propose expanding this system by integrating wildfire risk conditions alongside drought conditions.

Proper safeguards should be implemented, including total allocation caps, minimum instream flow requirements to mitigate potential environmental damage, and emergency wildfire allotments for at-risk communities. Water allocation legislation should be revised to mandate honest reporting of water use, and explicitly set aside allocations for rights holders in regions of greater environmental risk.

V. Conclusion

Precipitation, wildfire, and water-supply data from the comparative regions of Southern, Central, and Northern California indicate that in areas with lower water availability, wildfire risk is also higher. The state's current water management legislation is rigid, lacks enforcement and transparency, and fails to account for real-time trends such as the surge in wildfire frequency and risk.

To address these limitations, water allocation should shift to a more priority-based approach rather than first-come, first-served, with particular emphasis on reserving water supplies to mitigate environmental risks such as wildfires. The expansion of water markets will enable California to meet the state's flexible water demands.