Posts Tagged: wildfire

Urban wildfire impacts water, soil and wildlife

UC experts offer tips on testing drinking water, rehabilitating gardens

As residents start to clean up after the Los Angeles County wildfires, the aftermath will continue to impact water and natural resources in and beyond the fire areas, according to water experts at University of California Agriculture and Natural Resources.

Urban wildfires have grown more frequent and intense in the past decade. Record dryness and high winds created conditions capable of enormous heat and destruction; in these types of wildfire events, infrastructure systems – including water supply and electricity – may be affected.

For example, high heat created in urban wildfires can damage or destroy parts of a water distribution system, which disrupts supplies and introduces risks.

“Volatile organics and carcinogens can enter drinking water through compromised parts of the system that get melted by fire,” said Erik Porse, director of the California Institute for Water Resources. He added, “When distribution systems are damaged or face heavy demands, pipes can lose pressure, allowing bacterial growth.”

Water agencies in affected parts of Los Angeles County responded to these risks by monitoring water quality and releasing “do not drink” advisories in affected areas. Such notices are not unusual following disasters, but are jarring for residents who are accustomed to reliable household water. 

Ash, runoff can contaminate supply of drinking water 

If wildfires occur in watersheds that supply cities with water, ash and polluted runoff may contaminate water bodies in fire zones.

“Water treatment systems may be unable to treat incoming water if that water has high levels of solids or contaminants,” Porse said. 

These risks arose with the Hughes Fire near Castaic Lake, which supplies drinking water to parts of northern Los Angeles County. As the fire spread last week, water agencies in Los Angeles were monitoring the situation closely.

Many areas of Los Angeles also rely on groundwater. Future rains can cause contaminants to infiltrate into groundwater basins and create similar treatment challenges for water agencies.

Local water agencies are the best source of information to find out if drinking water is safe. During times of both routine operations and disasters, water utilities are subject to stringent standards and they monitor water quality in their systems as required by law.

“If a water utility publishes ‘do not drink' or ‘boil' advisories in your area, follow directions in the notice and stay up-to-date through website and social media updates,” Porse advised.

Edith de Guzman, UC Cooperative Extension specialist in water equity and adaptation policy at UCLA, added, “Residents who are not in such advisory areas should feel confident that their utility is monitoring the situation and that their water is meeting regulatory standards and is safe.”

Anyone who has concerns about the quality of the water in their home or office can get their water tested. “Water testing can always provide residents or business owners more information and it's important to understand how to interpret results,” said Porse.

Researchers at UC ANR and the Food-Energy-Water Systems for the Underserved lab at UC Merced published a fact sheet with resources on how to test water and understand the results.

Mudslides, degraded waterways other possible effects of wildfires

While rain would reduce overall wildfire risk, as little as a half-inch of rain in a short period of time could also trigger mudslides or debris flows because intense fires alter the ecosystem.

“Mudslides are a danger in areas burned by wildfires because the fires can destroy vegetation that would usually do two things – soak up some of the water and help keep the soil in place,” said Hope Hauptman, assistant project scientist with California Institute for Water Resources. “So, without that stabilizing plant cover, rain can run off quickly, and the exposed soil – particularly on steep slopes – can turn into dangerous mudflows.”

In addition to removing soil-stabilizing plants, intense fires can change soil characteristics, causing it to repel rather than absorb water, said Monica Palta, UC Cooperative Extension specialist in urban water quality, health and justice at UC Irvine.

“A wildfire with high heat can cause sandy soils in particular to become hydrophobic, or repel water,”Palta said. “A hotter fire creates a waxy substance, formed from burned plant material, that coats the soil and inhibits its ability to infiltrate water and elevates surface runoff.”

Elevated surface runoff increases erosion and causes toxic soils and ash to wash into rivers and the ocean.

“Ash from wildfires can contain heavy metals that are toxic to fish and other animals,” Palta said. “Ash from urban wildfires can have additional types of toxins from melted plastics and other materials in human-built structures like houses.”

Wildfire ash also contains large quantities of nutrients like phosphorus and nitrogen. When those nutrients enter coastal waterways, they can trigger harmful algal blooms, which is bad for swimmers, surfers and wildlife. “Algal blooms can produce their own toxins, and the large amount of decomposing algae in an algal bloom consumes oxygen that fish and other aquatic wildlife need to breathe,” Palta explained.

These water quality issues can persist for years after a fire.

“When contaminated water infiltrates soil or is taken up by plants, the contaminants have a good chance of being bound and stored there,” Palta says. “As wildfire destroys plant communities and causes soils to repel water, it causes not only the release of contaminants into the environment, but reduces the ability of an environment to capture and store those contaminants before they reach a river or the ocean.”

Cleanup crucial in rehabilitating garden after fire 

To remove the harmful substances in soil and improve infiltration, Palta recommends taking off the top 6 to 12 inches of soil in gardens, disposing of the soil in plastic bags placed in a trash bin (do not discard in a green bin or compost pile), and then adding new, clean soil to garden beds. 

Mixing in compost also will improve infiltration and bind contaminants like heavy metals. 

“I would advise engaging a professional to remove the soil because you need to wear correct protective equipment to avoid exposure,” she added. “You can wash ash off of garden plants with water from a hose, but be aware that the contaminants will then go into the soil, so wash your plants before removing soil from the yard. Scorched plant material should be removed from the garden, as it may contain contaminants.” 

She also recommends replanting vegetation in the “clean” soil as soon as possible, and taking steps to control erosion. 

“To stabilize slopes and hillsides, you can lay logs or branches perpendicular to the slope to block water and erosion down the slope,” Palta said. 

UC Master Gardeners of Butte County also have a list of tips on how to mitigate damage on a landscape burned by wildfire when heavy rains begin.

The Los Angeles County Department of Public Health encourages testing soil and water (if not done by your local water provider) prior to starting a garden. On page 16 of the agency's Soil and Water Testing Guidelines for Home and Community Gardens is a list of soil-testing labs. 

Climate, wildfire, wolves topics of Feb. 18 rangeland discussions in Davis

Rustici Rangeland Science Symposium to address California's changing landscapes

Ranchers, land managers, conservationists, policymakers and scientists will gather to discuss the evolving challenges and opportunities in managing the state's rangelands at the 2025 Rustici Rangeland Science Symposium on Feb. 18at UC Davis.

“The 2025 symposium will bring together a broad range of perspectives to tackle some of the most pressing issues facing California's working landscapes, which are crucial to both the state's economy and environmental health,” said Leslie Roche, professor of Cooperative Extension in rangeland management at UC Davis.

Key themes for the 2025 symposium, "California's Changing Landscapes," include:

1. Climate and Weather: Understanding the changing climate, impacts on rangelands and potential solutions for adaptation.
2. Wildfire Resilience: Expanding strategies to mitigate wildfire risks and post-fire recovery of rangelands.
3. Ranching with Wolves: Examining the scale of wolf-cattle conflicts on ranches and assessing the economic impacts of ranching with wolves.

“This symposium aims to spark meaningful conversations and cultivate new partnerships that will drive solutions to the critical challenges of sustainablerangeland management,” said Ken Tate, professor of Cooperative Extension inrangeland watershed sciences at UC Davis.

Presentation and speakers include:

• “Building Climate Resilience across California's Rangelands: Approaches for Sustainable Ranching, Adaptive Management, and Collaborative Conservation,” by Roche
• “Climate-smart Agriculture: Rangeland Soil Health,” by Anthony T. O'Geen, professor & soil resource specialist in Cooperative Extension, Russell L. Rustici Endowed Chair in Rangeland Watershed Science, UC Davis Department of Land, Air and Water Resources
• “Increasing hydroclimate whiplash in California: Implications for California's grasslands and shrublands,” via Zoom by Daniel Swain, climate scientist, California Institute for Water Resources, UC ANR and Institute of the Environment & Sustainability, UCLA

• California Wildfire & Forest Resilience Task Force: Expanding the use of prescribed grazing as a landscape management tool, by Patrick Wright, director of the Governor's California Wildfire and Forest Resilience Task Force
• “State-of-the-Art Strategies for Reducing Wildfire Risk on Forests and Rangelands,” by Dan Macon, UCCE livestock & natural resources advisor, Central Sierra; and Bianca Artadi Soares Shapero, targeted grazing practitioner and project manager at Star Creek Land Stewards Inc.
• Ranching through Wildfire, by Tracy Schohr, UCCE livestock & natural resources advisor, Plumas, Sierra and Butte counties

• Status of Gray Wolf Population and Conservation in California, by Axel Honeycutt, state wolf coordinator, California Department of Fish and Wildlife 
• Understanding the Scale and Scope of Wolf-Cattle Conflict on California's Ranches, by Tate
• Quantifying the Economic Impacts of Ranching with Wolves, by Tina Saitone, professor of Cooperative Extension, UC Davis Agricultural and Resource Economics

Closing comments will be made by Lynn Huntsinger, professor of rangeland ecology and management and Russell Rustici Chair in Rangeland Management, in the UC Berkeley Department of Environmental Science and Policy.

After the presentations, participants are invited to network and engage in informal discussions during a social and poster session.

Register at https://bit.ly/2025RusticiSymposium. For more information and updates, visit https://rangelands.ucdavis.edu/2025-rustici-rangeland-science-symposium.

Established in 2012, the Rustici Rangeland Science Symposium celebrates the work of Russell L. Rustici and his commitment to advancing sustainable rangeland management. The event serves as a vital forum for engaging conversations on rangeland management, conservation, and policy.

The symposium is funded in part by the UC Davis College of Agriculture and Environmental Sciences' Russell L. Rustici Rangeland & Cattle Research, Education and Extension Endowment. 

UC ANR Fire Network shares resources on reducing impacts of wildfire, smoke

Fire advisors offer guidance on minimizing damage, preparing for evacuation, protecting against smoke

With exceptionally dry conditions persisting in many parts of California, residents should double their efforts to prepare homes, families, businesses and communities for potential wildfire and smoke impacts, according to University of California fire experts.

“Even as firefighters make progress in containing the Los Angeles-area fires, communities must continue to be vigilant across Southern California and other regions that are experiencing this historically dry ‘wet season,'” said Lenya Quinn-Davidson, director of UC Agriculture and Natural Resources' Fire Network.

The Fire Network is a team of UC Cooperative Extension fire and natural resource advisors, specialists and staff who deliver fire-related research, outreach, and support for communities across the state.

The experts have assembled a website with a wide range of relevant resources at ucanr.edu/fire. Quinn-Davidson said the “Wildfire Preparedness” page contains essential information on how to protect homes and property from fire: https://ucanr.edu/sites/fire/Preparedness.

“There are many small but significant tasks that people can complete to shore up potential danger spots and minimize fire damage,” she emphasized.

Experts highlight six things to do before evacuating

For communities where evacuation warnings have been issued, Quinn-Davidson and other members of the Fire Network urge residents to do six key things in advance of an actual evacuation order.

• Close windows, fireplace screens, pet doors and skylights.
• Move inside patio cushions, brooms and door mats; tie open wooden gates that attach to the house or deck to prevent a fire from traveling from the fence to the house.
• Relocate any propane tanks away from the home.
• Stage buckets of water and garden hoses in visible locations.
• Dress for evacuation: long sleeve cotton clothes, sturdy shoes, hat and face protection and leather gloves.
• Put your “go-bag” in your vehicle and share your evacuation plans with out-of-area family or friends.

The UC ANR Fire Network website also includes downloadable checklists – in English and Spanish – for your go-bag (https://ucanr.edu/sites/fire/Safety/Evacuation/Preparing_a_Go-Bag/) and for a host of important pre-evacuation tasks for your household, property, pets and livestock (https://ucanr.edu/sites/fire/Safety/Evacuation/).   

“These actions can make a tremendous difference when preparing for wildfire, even just hours before evacuation,” Quinn-Davidson said.

Take precautions to protect yourself from smoke

During wildfire events, smoke from nearby fires can blanket nearby areas. A primer on harmful health effects, a list of tips for reducing smoke exposure, and other resources and links can be found on the UC ANR Fire Network site: https://ucanr.edu/sites/fire/Safety/Air_Quality_and_Smoke/.

“It's important to monitor your local air quality so you can mitigate smoke impacts,” said Katie Low, statewide coordinator for UC ANR's Fire Network. “One go-to resource is fire.airnow.gov. If the AQI – Air Quality Index – is high, I would limit my outdoor activity, wear an N95 mask if I do go outside, and run my air purifier.”

For instructions on making a DIY air cleaner, creating a “clean air space” in your home and fitting an N95 mask properly, visit the California Air Resources Board's “Smoke Ready California” page: https://ww2.arb.ca.gov/smokereadyca.

A wildfire can also contaminate drinking water to an extent beyond what boiling can remedy; residents should check with their local water department or district for any advisories.

Another useful tool is the crowd-sourced #FireMappers fire activity map – powered by the National Alliance for Public Safety GIS Foundation, GISCorps, and CEDR Digital – accessible through the UC ANR Fire Network site: https://ucanr.edu/sites/fire/Safety/Current/. 

Media Resources

Lenya Quinn-Davidson: lquinndavidson@ucanr.edu; (707) 272-0637 

Katie Low: katlow@ucanr.edu; (530) 889-7385

UC wildfire expert: Lack of rain ‘primary factor’ in L.A. fires

 

Siting, design of communities key to limiting catastrophic damage

Jan. 8 statement about wildfires in Southern California by Max Moritz, University of California Cooperative Extension statewide wildfire specialist based in Santa Barbara

“Santa Ana winds can be expected at this time of year, but this episode seems unusually strong. Some people are focusing on climate change and higher temperatures drying out the vegetation, but that's not really the primary factor here. It's the lack of rainfall that's unusual, and that's likely also related to climate change. More erratic and extreme precipitation patterns – drier dry periods and wetter wet periods – are extending the fire season. We still haven't started our typical fall and winter rains, and it's January! By this point of winter, usually it has rained so fuels contain more moisture and are not as flammable.”

How to prevent catastrophic wildfires?  

“We can reduce the various sources of ignition, especially during red flag conditions, but we really need to treat wildfire as a public health concern and address it through urban planning.  

We can retrofit existing communities to better withstand such events. Providing better water supply and distribution systems, hardening homes, establishing evacuation plans for communities, and training community members how to live with fire and reduce risks. 

We should prepare for the inevitable by building and rebuilding differently, such as in the siting and design of communities in fire-prone environments. Placement of communities on the landscape, such as near bodies of water and agricultural buffers, and how they are laid out can minimize their exposure to wildfire. This goes well beyond structure-level building codes.”  

Wildfire takes toll on mental, physical health of food producers

Farm Bill could support awareness of help available

The people who produce our food need support – especially in the areas of mental and physical well-being – to recover from increasingly widespread wildfire, scientists have found. The federal Farm Bill could help, but it is languishing in Congress (an extension of the previous Farm Bill was passed in late December 2024).

Postdoctoral researcher Natalia Pinzon Jimenez used surveys to hone in on the experiences of ranchers and farmers impacted by wildfire. Pinzon recently earned her Ph.D. at UC Davis and produced her findings with a team that included Leslie Roche, a professor of Cooperative Extension in the Department of Plant Sciences.

The team surveyed more than 500 ranchers and farmers affected by wildfires between 2017 and 2023. Pinzon recently summarized her findings in this research report. She also recently launched a website, Wildfires & Agriculture, based on her findings. Its goal is to help producers become more resilient to fire by providing tools, improving research and effecting policy.

Financial and technical assistance also matter, but are secondary, said the producers who participated in the surveys.

“The No. 1 wildfire impact for ranchers is on their physical and mental health,” said Tracy Schohr, a research team member and livestock and natural resources advisor in Plumas, Sierra, and Butte counties with UC Agriculture and Natural Resources (Schohr earned her master's degree with Ken Tate, also a professor of Cooperative Extension in the department.)

“This underscores the need for future United States Department of Agriculture disaster programs to prioritize physical and mental health and emphasizes the importance of USDA investment in training staff and partners in trauma-informed approaches to aid farmers and ranchers affected by disasters,” Schohr argued.

In addition to being scorched by wildfire, farmers and ranchers are on the front lines of wildfire response, both on their properties and in their communities. When it's not wildfire season, they manage future risks by reducing fuel loads on their properties, installing off-grid systems and water storage, planning for wildfire response and training employees, Pinzon reported.

Need for greater awareness of help available

While producers were optimistic about their chances of recovering from wildfire, Pinzon found they have a limited financial safety net supporting them. Most producers relied on personal savings to recover from significant losses. Small producers, those using organic or sustainable practices, beginning producers, first-generation producers and people renting their land all had fewer resources, including crop insurance.

In addition, 78 percent of farmers and 58 percent of ranchers did not use financial assistance offered through the USDA to cope with disasters, Pinzon reported. Many didn't even know such assistance is available, or they reported the application process was too difficult.

All those pressures led to a quarter of the respondents admitting they had considered shutting down their operations.

Pinzon pointed to the federal Farm Bill as a source for funding greater collaboration between the USDA and on-the-ground organizations such as Cooperative Extension. The aim would be “to raise awareness, expand access to assistance programs and provide science-based solutions for wildfire recovery,” Pinzon recommended.

Surveys lead to more insights

Pinzon's work is part of a larger, statewide effort to use surveys and interviews with ranchers and farmers to understand their needs, direct scientific inquiry and develop solutions to their problems.

The team includes the University of California, UC ANR, federal, state and local agencies, producer organizations and private individuals. The surveys go back to 2011 and were conducted by Roche and a network of colleagues.

Read about California ranchers' response to drought and their needs for staying strong.

Farmers and ranchers: Learn what you can do

You can prepare for wildfire on your land. Get free, online information through Farmer Campus, co-founded by Pinzon with support from the USDA. Start by downloading your Wildfire Preparedness Workbook. It includes practical, hands-on activities to help you get your operation ready to survive a fire.

This article was first published on the UC Davis Department of Plant Sciences news site.

Read more