Tres Rios Wetlands Controlled Burn Planned for October

October 12, 2023 2:00 PM

The City of Phoenix, in coordination with the Arizona Department of Forestry and Fire Management (DFFM), is planning to conduct a controlled burn at the Tres Rios Wetlands in October 2023. The burn is tentatively scheduled to begin on Tuesday, Oct. 17, but that is subject to change depending on the weather conditions. The event is expected to produce a significant smoke plume visible in southwest Phoenix and the surrounding areas, and 91st Avenue will be closed from the 91st Wastewater Treatment Plant North Gate to Baseline Road from 8 a.m. to 7 p.m.

The primary purpose of the operation is to reduce dense vegetation and is part of the ongoing process of restoring vital riparian habitat. Fire is nature's way of providing nutrients to the soil, removing invasive species of plant life, and improving the overall health of an ecosystem.

Why is Burning Necessary?

Previous attempts to mechanically maintain Tres Rios vegetation have proven to be time-consuming and cost prohibitive. After researching alternative methods, the Phoenix Water Services Department identified control burns as an optimal means to maintain the wetlands. Additionally, a controlled burn reduces hazardous fuels, protecting surrounding communities from extreme fire.

Why is the Burn Planned for October?

Per the United States Fish and Wildlife Service Tres Rios Safe Harbor Agreement, control burns may be conducted from October through February to avoid impacts during the breeding season. October has been identified as the ideal time to conduct the preliminary Tres Rios Control Burn, but that could change depending on weather conditions and other factors.

How Big is the Burn Area?

One entire Tres Rios Flow Regulating Wetland (FRW) cell is allowed to be burned annually. This initial controlled burn will only target half of the FRW-3 cell, either Area 1 or Area 2, as identified in the figure below.

How Will the Fire Be Extinguished?

After the control burn is completed, the cell will be flooded to extinguish any smoldering flames. Water quality will be monitored and confirmed acceptable before the release of water from the cell to the Tres Rios Overbank Wetlands. That will include allowing sufficient time for any fire debris to settle out and the completion of a water quality sampling plan.

What is the Phoenix Fire Department's Role?

The Phoenix Fire Department will administer the controlled burn with guidance from the Arizona Department of Forestry and Fire Management.

The controlled burn will also serve as a training opportunity for the Phoenix Fire Department's Wildland Urban Interface program, which will provide Phoenix firefighters with the necessary skills, certification, and experience to battle wildfires that threaten the City of Phoenix. In addition, the controlled burn may also give the Phoenix Police Department's Firebird helicopter crew a training opportunity.

The specific training will be focused on the following certifications necessary to coordinate and fight wildfires safely and effectively:

Wildland Firefighting 1 and 2
Wildland Engine Boss
Strike Team Leader
Task Team Leader
Incident Commander Type 4
Burn Boss
Drone Mapping and Incident Command integration training

Who is Involved with the Controlled Burn?

In addition to the Phoenix Water Services Department, Phoenix Fire Department, and Arizona Department of Forestry and Fire Management, there are other relevant parties and agencies that may be affected by the Tres Rios controlled burn:

United States Fish and Wildlife Service (USFWS)
United States Environmental Protection Agency (EPA)
Gila River Indian Community (GRIC)
Maricopa County Air Quality Department (MCAQD)
Arizona Department of Environmental Quality (ADEQ)
Phoenix-Goodyear Airport
Sky Harbor International Airport
Emergency 911 Call Center
Residents and other stakeholders

What is Tres Rios?

The Tres Rios Wetlands receives reclaimed water from the 91st Ave Wastewater Treatment Plant (WWTP) and are maintained by the City of Phoenix Water Services Department.

The Tres Rios Environmental Restoration project involves the rehabilitation of nearly 700 acres in and around the Salt River, restoring a vital wetland and riparian habitat. It consists of the Tres Rios Flow Regulating Wetlands (FRWs) and Tres Rios Overbank Wetlands (OBWs). They are located just west of 91st Avenue, south of Broadway Road. The Tres Rios FRWs receive treated wastewater from the 91st Ave WWTP, and act as the final polishing step in the treatment process. Reclaimed water is then discharged from the FRWs to the OBWs before being conveyed back to the Salt River. The Tres Rios FRWs are closed to the public. However, the Tres Rios OBWs are open to the public through a free access permit system.

The lush and scenic Tres Rios is now home to more than 150 species of birds and animals like muskrats, raccoons, skunks, coyotes, bobcats, and beavers. The beautiful cottonwood groves, willows, mesquites, and other desert shrubs around the reed-lined ponds and along the trail attract many migratory and wintering songbirds.

Media Staging Areas:

Depending on the wind, media can stage at either the northwest corner of 91st Avenue and Paradise Road (please stay at least 100 feet away from the power lines and do not use a tall mast) or the southeast corner of 91st Avenue and Southern Avenue. Those interested in covering the event should call or email the media contacts listed below for guidance on how to access the area. Fire experts will be available for interviews at the scene. For the safety of the crews and to minimize disruptions to operations, please do not fly drones in or around the controlled burn area.

Tres Rios