Yampa River flow slowing in Moffat County, but mosquitoes sticking around with moisture
It was raging at more than 10,000 cubic feet per second and still hasn’t relinquished much of the low-lying areas of Craig, but the Yampa River’s baseflow continues its drop after peaking June 23.
According to United States Geological Survey data, the Yampa River’s June run was a torrent — rising up to 10 feet on the river gauge below Craig. The Yampa River is now flowing at a slower, but still a quicker pace than normal at a little more than 3,000 cubic feet per second.
“The snow is melting and will continue to melt and then we’ll be done with the runoff,” said Erin Light, an engineer with Colorado’s Division of Water Resources. “We’re certainly way at the tail end of the runoff. But some of that runoff is still coming off. Also the snow at the lower elevations is soaked into the ground and creating an underground source of water in the Yampa — a higher baseflow. So I do think we will see a higher baseflow because of all the moisture.”
This time last year, the Yampa River in Craig was but a trickle — about 225 cfs on July 13, 2018, according to USGS data. But Light said there’s nothing in that data suggesting residents of the Yampa Valley should be worried.
“I’m not seeing anything alarming given the weather we’ve had over the last six months seeing these flows this high,” Light said. “Yeah, it is substantially above normal, but we also had a slow warming up, a slow runoff, and a very high water year. So, this is not alarming to me in any way.”
Some residents were alarmed when a mosquito tested positive for West Nile virus early this month — a product of the high water sitting across much of the area. City and county officials soon began their yearly ground and aerial spraying for mosquitoes, including Friday in Maybell and possibly into Monday, July 15.
Adam Tucker, a pilot whose Mountain Air Spray company has flown the skies above the Yampa Valley for decades, said they are using Perm-X 3030, a common adulticide for mosquito control.
“It’s permethrin,” Tucker said of the pesticide’s active ingredient. “It’s widely used. They make clothing with permethrin in it.”
According to a 2011 amended registration found on the Environmental Protection Agency’s website, Perm-X 3030 can be toxic to aquatic organisms in bodies of water when runoff occurs. The EPA advises to not apply Perm-X 3030 over bodies of water and to properly dilute treatments in aerial applications to .0007 pounds per acre.
Tucker said his company follows the EPA’s guidance closely in this area.
“The chemicals are all regulated by the EPA and the EPA says they’re safe at the levels we’re using them,” Tucker said Thursday. “They’re labeled for the exact uses were doing.”
Jesse Schroeder, Moffat County’s weed and pest director, said he will continue to communicate with residents about the days and times of vector control operations.
“That’s the purpose of our public service announcements on this is to let the folks know what the application times are going to be, so they can choose to be inside,” Schroeder said Thursday. “We want to give them enough headway to do that.”
In the EPA’s amended registration for Perm-X 3030, the agency said the treatment is highly toxic to bees on blooming crops.
Beth Conry, the former president of the Colorado State Beekeepers Association, said residents and their governments often overreact to increased mosquito presence in an area and end up killing more than just mosquitoes.
“We think that spraying will fix this problem, but it really doesn’t,” Conry said. “It creates a lot of problems.”
Conry said larvacides are a good alternative to killing adult mosquitoes with pesticides. She said if adulticiding is used, spraying at night or later in the evening is better to spare pollinating insects like bees.
Schroeder said his agency is doing that in their treatments.
“That’s another reason we apply late in the evening to avoid as much of that as possible because the bees go home at night,” Schroeder said. “We do take all of that into consideration. We want to save the bees too.”
Tucker said the real public health concern isn’t the chemicals used to control mosquitoes — it’s the mosquitoes whose diseases kill almost a million humans across the globe every year.
“The thing to keep in mind is the mosquito is the public health issue,” Tucker said. “It’s always the mosquito, not the chemical.”