Title
Wildland Urban Interface Fire Preparedness - Citywide
Description
The report updates the Phoenix City Council on the City's preparedness for Wildland Urban Interface fires. The report covers fire threats, ongoing mitigation efforts, and the collaboration between the Phoenix Fire Department, Water Services Department, and the Office of Emergency Management to manage and reduce Wildland Urban Interface fire risks.
THIS ITEM IS FOR INFORMATION AND DISCUSSION.
Report
Summary
The Wildland-Urban Interface (WUI) refers to areas where human development intersects with undeveloped wildlands. Wildfires in these areas have become an increasing concern in Phoenix, particularly where natural fuels dry out in the spring and summer, elevating the risk when temperatures exceed 105°F and humidity drops below 15 percent.
In 2024, the Phoenix Fire Department (PFD) reevaluated WUI risk areas and identified 41,436 acres, covering 42,638 addresses. These areas are prioritized for community outreach, firefighter training, pre-incident planning, and resource deployment. During times of elevated WUI risk, the Fire Department’s WUI Deployment Program is activated, ensuring a surge of fire resources to quickly address brush fires in these areas.
To maintain a continuous state of operational readiness, the PFD has developed a WUI management cycle that exists in perpetuity. In the fall, after-action reports and assessments are conducted. In the winter and early spring, fire fuel reduction programs and training are completed. In the late summer, supplemental resources and associated WUI plans are activated. The cycle repeats annually.
Through unified coordination and standard operating procedures, the PFD and the Water Services Department (WSD) work in unified coordination, following established Standard Operating Procedures (SOP) to ensure an uninterrupted water supply, which is essential for effective firefighting and community safety. During incidents requiring large amounts of water, WSD provides guidance on the selection of fire hydrants to use and assists PFD in navigating from smaller water mains to larger ones, where higher water flow can be accessed. Additionally, WSD helps identify areas that can be isolated to boost water supply when needed. This collaborative effort ensures that fire hydrants and other water sources continue to function optimally, even under the most challenging conditions. Such coordination is crucial to safeguarding the lives of both Phoenix residents and first responders.
Fire Hydrant Maintenance
In 2021, Water Services conducted a comprehensive review of the Fire Hydrant Maintenance, Repair, and Replacement Program to ensure consistent and regular execution of preventative maintenance, inspections, testing, repairs, and replacements of fire hydrants across the City’s water distribution system. The primary goal of Water Services continues to be the diligent testing and maintenance of its 57,000 fire hydrants annually, ensuring compliance with the City’s fire code. The 2021 replacement backlog was completed by December 2022. WSD assesses and updates the Fire Hydrant Maintenance, Repair, and Replacement Program each year. On average, less than one percent or 520 hydrants are identified for replacement and included in the WSD's annual maintenance, repair and replacement program. In addition, WSD also regularly exercises its valves, adhering to industry best practices to ensure the entire inventory operates efficiently and effectively.
Water Distribution System and Design
WSD is responsible for the operation and maintenance of the Phoenix water distribution system, which not only supplies drinking water to customers but also provides the required fire flow, as determined by the Phoenix Fire Code. Fire flow refers to the flow rate of a water supply with a residual pressure of 20 psi, available for firefighting purposes. The City’s 610 million gallons a day water treatment capacity ensures a reliable backbone to meet the demands of the City.
Phoenix’s 7,000-mile water distribution system spans an elevation range between 940 feet and 2,145 feet. Due to this variation, the City is divided into 80 pressure zones, each spanning approximately 100 feet in elevation to ensure standardized pressure targets throughout the City. These pressure zones are served by various water supply systems, including water mains, storage tanks, pump stations, and Pressure-Reducing Valve (PRV) stations. Water demand, which includes the amount of water required for customer needs and fire emergencies, is a key factor in system design. The major water zones are designed with at least two ways to bring water into the zone. This redundancy ensures a reliable water supply throughout the City. Water systems are designed around the following:
Average Day Demand: The total volume of water consumed over a year.
Peak Day Demand: The highest water demand during any 24-hour period.
Peak Hour Demand: The highest water demand during any single hour.
The City’s water supply systems are designed to meet peak day demands and required fire flow, while maintaining system pressure above 25 psi and keeping velocities in distribution mains below 10 feet per second. Non-emergency conditions demand system pressures between 50 psi and 100 psi, with velocities below 5 feet per second. There are areas of the system that do not meet these standards or fire flow requirements.
The 480-million-gallon water storage throughout the City provides operational resiliency to meet peak hour demand, fire flow storage, and emergency reserves in case of main breaks, system valve issues, or pump station failures. For areas without storage tanks, the pump stations and/or PRVs that feed the zones are required to have larger capacities, primarily to meet fire flow requirements.
The PFD and the WSD are committed to working collaboratively to assess the WUI areas and develop infrastructure strategies that are economically sensible while maintaining water quality and public safety standards. Options include proactive wildfire prevention strategies, such as reducing fire fuels, clearing vegetation near homes, and using fire-resistant materials as well as water infrastructure to support wildfire suppression efforts.
Phoenix Fire Department’s Community Risk Reduction and Prevention
The PFD, in partnership with other agencies, such as the Phoenix Police Department, also work to reduce fire risk in WUI areas. This includes conducting fuel reduction programs, pre-incident training, and activating additional resources during the summer months. The PFD coordinates with local, county, state, and federal partners to develop and maintain joint SOPs for tactical fire suppression.
The Neighborhood Services Department has been actively working to mitigate the risk of urban fires along SR 51 and SR 101 by facilitating collaborative discussions with key stakeholders. These stakeholders include the Arizona Department of Transportation (ADOT), Bureau of Reclamation, Central Arizona Project, State Land, State Forestry, Phoenix Police-Black Mountain Precinct, Phoenix Fire, and the Office of Homeless Solutions.
The Street Transportation Department contributes to the reduction of potential fire fuel through the maintenance of conveyance channels and washes under their control by implementing vegetation management. Additionally, Street Transportation actively manages vegetation along major City streets within the public right-of-way and is responsive to the PFD for addressing areas of potential safety concerns.
By bringing these diverse groups together, we've seen significant improvements in communication, identification of high-risk areas, and a clearer understanding of each agency's jurisdiction and property boundaries. Fuel reduction and clean-up projects are currently underway in collaboration with State Forestry, State Land, and ADOT to further reduce fire hazards in the region.
Emergency Management Coordination
Additionally, the Office of Emergency Management plays a key role in coordinating responses to WUI incidents. This includes determining whether evacuations are necessary, implementing traffic management plans, and activating sheltering plans if needed. The office works closely with PFD, WSD, and other City and state agencies to ensure a well-coordinated response.
The City of Phoenix is committed to enhancing public safety and providing effective wildfire mitigation strategies in WUI areas. Through collaboration between the PFD, WSD, the Office of Emergency Management, and other stakeholders, the City ensures a comprehensive approach to wildfire preparedness and response. The efforts focus on maintaining reliable infrastructure while considering cost-effective solutions to support long-term fire resilience.
Department
Responsible Department
This item is submitted by Assistant City Manager Lori Bays, Deputy City Manager Ginger Spencer, Phoenix Fire and Water Services departments and Office of Emergency Management.