Weeks after drone pilots from the Menlo Park Fire Protection District provided the public with detailed aerial views of properties damaged by a wildfire in and around Redding, plans are now afoot to conduct aerial surveys of the fire district to determine exactly what is on the ground, as well as the moisture content of vegetation, including tree canopies.
The district has an interest in exactly what burns in a fire, district Fire Chief Harold Schapelhouman told The Almanac. For example, when looking down at a shed using a standard Google Earth map, "you just can't make it out," he said.
As for vegetation moisture levels, dead or dying trees are fuel for fires, and their proximity to a structure can determine whether that structure is consumed by flames or spared, Schapelhouman said.
The technology that could be used to perform these surveys – there could be several per year, Schapelhouman said – is in flux.
At first, based on a conversation with the drone crews, district officials were thinking of flying its drones at an altitude of 200 feet to read moisture levels and take high-resolution photos, Schapelhouman said.
To capture the entire district Atherton, Menlo Park, East Palo Alto and adjacent unincorporated areas the drones would do what was done above the damaged parcels in and around Redding: make consecutive passes over the area in the manner of tractors plowing a field.
Such a project, with drones flying over homes, would be likely to raise privacy concerns among residents.
A few days later, in another interview with The Almanac and after more conversation with drone crews, Schapelhouman distanced the district from a drone-based survey. "It's off the table, for now," he said. "We're going to explore (satellite surveys) with Google first. It depends on what resolution they have. ... We're going to try and work through them first to see if we could get what we need."
Moisture levels would be rendered as a color-coded map of the district, he said.
High-resolution photos, in addition to giving firefighters clues about what a fire consumes, can provide before-and-after views of destroyed parcels, as was done after the 2017 fire in Santa Rosa, Schapelhouman said.
Satellite surveys, if done through Google, could come at no cost to the district, Schapelhouman said, noting the company has, at times in the past, not charged the fire district for services. Google has provided free satellite images associated with a tornado in Kansas and images of the gas main explosion in San Bruno, he said. And on several occasions, the company sought the fire district's opinion on ideas to help people obtain information after a disaster.
A survey of the moisture content of vegetation would focus on wooded areas, including the tree-lined streets of Atherton and Menlo Park. "Atherton and Menlo Park have huge tree canopies," Schapelhouman said. "We've never looked at the health of the tree canopies."
A color-coded map would enable the district to "focus on where the dead and the dying (are)," along with vegetation in need of trimming.
Highly developed urban areas, such as parts of East Palo Alto and unincorporated North Fair Oaks, could be skipped, he said. "When you don't have the vegetation, you don't really need to do it," he said.
The moisture-content surveys would likely be done in the spring, ahead of the Fourth of July and its potential for illegal fireworks, and before the winter, since fire season in California is now a year-round phenomenon, he said.
If data on moisture content is unavailable from satellite sources, the district might try using a drone to take aerial photos, he said, noting that a test run could help in understanding the value of such a survey. "I (don't) know anybody that's done it," he added. "I wish I had someone to go talk to and ask."
Schapelhouman noted that staff can conduct such surveys of the district without first running the idea past the district's governing board.
Any such survey would be advertised in advance, he said.