BYU researchers studying canyon runoff in wake of Utah megafires

Payson • Peteetneet Creek, which tumbles down Utah’s Payson Canyon, is carrying a lot more than just water this spring. At times, it looks like a roiling mixture of Hershey’s chocolate powder and milk, with woody debris thrown in, according to ecological researcher Ben Abbott.

Much of the watershed drained by Peteetneet Creek burned in last summer’s Bald Mountain Fire. Abbott is exploring how the burn is affecting the quality and quantity of water coming off Utah County’s stretch of the Wasatch Mountains, which is still under a deep snowpack that contains about 40 percent more water than the long-term average.

“Fire is a really important disturbance. We wouldn’t have any aspen forests if we didn’t have fire. Those only recover after a burn,” Abbott said during a recent visit to a study site in Payson Canyon, one of 24 data-gathering locations on streams feeding Utah Lake.

“What was different about this fire was we had that extremely dry summer. Climate change contributed to that. And then that area had not burned for a really long time, so there were lots of fuels for a late season fire,” the Brigham Young University ecology professor explained. “It was what we call a crown fire, or a stand replacing fire, where it burned everything.”

At the Payson Canyon site, his team rigged data-collection instruments to a stake posted in the center of the stream channel. On the recent visit, the researchers discovered a burnt cedar branch wrapped up with the stake. They waded into the brown torrent and spent several minutes disentangling the branch that threatened to drag the instruments downstream.

Already this spring, high flows have knocked out instruments at two monitoring sites. Abbott prefers staking the equipment in the middle of the stream channel because the discharge rate can vary by a factor of 10 over the course of the day, peaking at 7 p.m and slackening over night as cooling temperatures slow the rate of melting. He also wants to avoid moving the instruments when streams taper to a trickle in the summer.

The Utah Department of Natural Resources’ Watershed Restoration Initiative is funding Abbott’s five-year study with a $500,000 grant.

“We’re looking at the difference between what those systems looked like before the fire and what’s happened to them after,” said Tyler Thompson, the department’s watershed program manager. The data produced will help guide management of the 144,000 acres burned in the Bald Mountain, Pole Creek and Coal Hollow fires as the land rebounds in coming years. Hunting quotas, for example, could be increased or decreased in some areas to change the number of deer and elk munching on the vegetation popping back up.

“We’re also looking to fund a lot of small low-tech structures within those watersheds that can slow down a lot of this debris flow and actually help that fire [area] to heal more quickly,” Thompson added.

The state already has seeded 34,000 acres burned in the Pole Creek and Bald Mountain fires, which blackened the northern and eastern sides of Mount Nebo, to stabilize the scorched soils, according to Daniel Eddington, habitat conservation coordinator with the Division of Wildlife Resources.

“Seventeen fire areas throughout the state were rehabilitated this past fall to help the ecosystem recover properly and as quickly as possible,” Eddington said. “However, the extent of the erosion damage in the coming months will depend on whether Utah experiences a warm spring that causes the snowpack to melt quickly or there is a more gradual warmup and the snowpack slowly melts.”

Last summer’s fires in Utah County charred a variety of terrain, reflecting different elevations, directional aspects and habitat types. Abbott already had been gathering data in this area because of his interest in Utah Lake, providing a baseline from which to build a study on the fires’ impact on water.

“We realized this would be a great opportunity to look at the streams that were burned and those that weren't burned,” he said, “so we can start to understand how wildfire affects the amount of water and also the chemistry of that water.”

His data-collection sites were installed on streams draining areas that were mostly burned, partially burned and not burned.

"There are about a dozen major tributaries to Utah Lake,” Abbott said. “We’re trying to understand all of the material that’s getting to the lake: how much nutrient; how much sediment; how much water. Water [quantity] is the number one defining characteristic of a lake.”

The monitoring stations take readings every 10 minutes, recording temperature, pH, dissolved oxygen and conductivity, a measure of dissolved material in the water. High-frequency data collection is key since the contents of streams change moment by moment with the weather, especially in the spring.

Abbott’s team visits each site weekly to download the data and take a precise reading of the stream’s flow rate. The researchers do this by mixing a kilogram of salt into the water about 100 feet upstream from the monitoring gear. The rate of change recorded in the water’s conductivity reveals exactly how many cubic feet per second are flowing down the channel, according team member Adam Norris, a BYU undergraduate.

Abbott likens his research to what doctors do with urine samples. Just as urine contains clues about what is going inside the body, streams reveal what is happening within the watersheds they drain.

“If the plants have all been burned, then they’re not pulling up nutrients from the soil and instead those nutrients can be washed out of the soil into the stream,” he said. “Later this year, in the places that have been burned, they’re going to be recovering and regrowing. They’re going to hold on to every molecule of nutrient and we’ll probably see those nutrient concentrations crash during the recovery period.”

So, yes, there is a lot to learn, and nature is providing an ideal lab from which to learn it.