Using GIS Analysis to Prevent Wildfires
A Study on the Los Angeles County
GIS Tools
Esri provides professional-level GIS tools. We used the Esri suite of products, and the three most important and most used were ArcGIS Online, ArcGIS Pro, and StoryMaps. These tools enable complex data analysis such as geostatistical interpolation for predictive modeling or network analysis for optimal route planning. This enables us to create complex datasets in ArcGIS Pro (Even possible in the ArcGIS online website). Additionally tools like GIS statistical and network analysis were used to better understand our map’s data and display. Two other major tools were predicting modeling and site suitability, which were each used to predict the areas that may be at risk in the future or those that need specific attention. Finally, using raster analysis helps us analyze spatial information within a grid dataset.
Our Methods
Our data can be visualized from a range of tabular data to thematic visualizations, or anywhere in between. This project creates a map based on various factors for visual comprehension.
This is a list of some analysis tools we've used:
- Calculate slope
- Surface parameters
- Select by attribute
- Select by location
- Intersect
- Buffer
- 15 x 15 convolution
- Classify raster and polygons
Mission Statment
Los Angeles has been historically afflicted with wildfires. All it takes to start a dangerous wildfire is a spark from a powerline and some dry brush. Wildfires are widespread in the Los Angeles area, with residential and commercial areas, critical infrastructure, and social facilities all contained within major risk areas. This project aims to protect Los Angeles residents and their homes from wildfires. There are hundreds of thousands of high-fire-risk acres in Los Angeles County. We aim to reduce this area to key locations that could start a wildfire; in the process, turning the unattainable task of clearing the entire county of brush into a more manageable one. We are working with various levels of government to facilitate brush clearance in this newly calculated area.
Historical Wildfire Burn Sites (1878-2021)
Collecting Data Online
Sources for the data used include government data and studies found on ArcGIS to create this map. This was mapped through Esri's ArcGIS Pro, by applying analysis functions such as raster. Finding accurate and usable data is difficult online, but we located many sources through extensive research. Below is an example of government data sourced from United States Geological Survey Data.
United States Geological Survey Data on Elevation
Partnership with Local Government
To perform Geoanalysis we needed to start with data. We requested and received WUI and Powerline data from our contact in Los Angeles County.
WUI
Dry brush ignites and spreads to vegetation and infrastructure very quickly which can keep burning for a long time and cause a fire to go from small and controlled to massive and wild in minutes. This is partially caused by the climate we live in California as it is a chaparral biome characterized by its short and mild winters, dry conditions, and very hot summers. The solution of removing the thick dry brush helps prevent fires from spreading easily. However, this comes with its own issues, as certain trees found native to California, mainly the giant Sequoia, require fire to release their seeds. An extra hazard is the Santa Ana winds, which both dry out brush and spread burnable plants, creating more places where fire could start. Vehicles on the freeway have previously started fire by falling off after a crash and bursting into flames, catching all the nearby brush on fire.
On the left are fire hazard severity zones throughout Los Angeles. This map identifies WUI, Wild Urban Interface transition areas where structures and human development meet with undeveloped wildland on the right.
We worked with our contact from the LA County government to obtain WUI data for this project.
Powerlines
Wind gusts can topple power lines, creating sparks that can ignite dry brush, causing wildfires. Knowing where they are, and how they intersect with areas likely to burn is important to clear vegetation near the range of power lines.
We worked with our contact from the LA County government to obtain powerline data for this project. This map shows major powerline locations throughout Los Angeles. We have also intersected the area of the powerlines with the area of urban zones. Cars, trucks, or other vehicles have the potential to knock over power lines and start fires.
This map shows major powerline locations throughout Los Angeles.
Calculating Priority Clearance Areas
Powerline Radius of Effect
When power lines fall or spark they can affect an area of around 300 meters in each direction. To find this area of effect we buffered our powerline data with a radius of 300 meters as shown on the right.
Calculating Wildfire Danger Zones
We intersected the WUI data with our powerline buffers to find high priority clearance areas.
Clearance Methods
Much of the priority clearance area calculated above is located on steep slopes, so a variety of clearance methods must be used to clear the dry brush. We needed three clearance methods, one for slight inclines, moderate inclines, and steep inclines. For slopes between zero and fourteen degrees, we determined manual human clearance to be the best method. Goats can be used for some steeper slopes but can't be used near freeways. Humans can't be used for some slopes. Lastly, prescribed burns can be performed at any slope angle using this information divide the priority clearance area into human, goat, and prescribed burn clearance areas.
Calculating Slope Geodata
To calculate slope for further Geoanalysis, we began with elevation data. By performing a 15x15 slope convolution on the elevation data, yielding a slope raster.
We classified this slope raster and generated polygons for goat, prescribed burn, and human-accessible areas
Human-accessible areas
To the right are priority clearance areas that are accessible to humans.
Prescribed Burn Priority Clearance Areas
Goat-accessible areas
To the right are priority clearance areas that are accessible to Goats.
What's Next?
As we continue to the next project phase, we will focus on community outreach. First, we'll enhance our maps, by expanding into other communities and conducting our own research and displaying that through maps. Our outreach will focus on communities and areas with severity zones and high-priority clearance areas.
Some actions that members of our community can take right now are:
- Report malfunctioning or damaged power lines. This can be done through neighborhood watch programs.
- Organize clean-up efforts to remove dry brush, considering solutions such as goats.
- Coordinate with local emergency services to monitor threats and address emergencies.
- Conduct regular fire drills so residents are familiar with evacuation procedures and emergency routes
Current USA Wildfire Dashboard
Results
We began with a wildfire hazard zone map taking up two-thirds (two million acres) of the Los Angeles County area. Clearing this area of dry brush is simply an unattainable goal. Through our project, we found forty-five thousand acres of land that if cleared of dry brush, would have a similar effect to clearing all two million acres stated above. Forty-five thousand acres is a much smaller area, far more manageable than two million acres. Through our communications with the Los Angeles County government, we have supplied them with this data to organize more efficient brush clearance. We could only accomplish this through the power of GIS, ArcGIS software, and our partnership with the Los Angeles County government. Because of our results, we are pleased to label this project a success.
