From The Pueblo Chieftain (Matt Hildner):
When the Papoose and West Fork fires burned 88,000 acres in the upper Rio Grande basin in 2013, water and wildlife officials feared the worst.
With 53,000 acres of the burn scars classified as moderate or severe, they feared rainstorms would wash dirt and ash into streams, suffocating fish and even clogging irrigation works on the San Luis Valley floor.
Those concerns have been squelched, if not by laymen’s observations, then by the work of a researcher at the Colorado School of Mines who’s spent the last three years studying water quality below the burn scars.
With some exceptions on the river’s tributaries, the Rio Grande’s water quality and its fish have survived fine.
“Nothing really changed on the Rio Grande,” said Ashley Rust, a doctoral student in hydrological science. “Everything looks great and still continues to look great.”
Rust, whose work was partially funded by the Rio Grande Watershed Emergency Action Coordination Team, installed six water-quality probes on the main stem of the Rio Grande and another four on tributaries that run through the burn scar.
There were no metals that exceeded water quality standards. There was initial concern that abandoned mines were burned and held the potential to leak pollutants…
Nor were there any increases in the amount of nutrients, such as phosphates, nitrates and nitrites, that sometimes happen after fire.
But measurements for suspended solids, an indicator of how much dirt is in the water, and turbidity, or water cloudiness, have spiked on the Rio Grande’s tributaries during rainstorms.
Problem areas, such as Trout Creek southwest of Creede, have either especially steep slopes or severely burned soils.
Those areas have had turbidity measurements that reach 50 nephelometric turbidity units — roughly the point at which trout begin to die from suffocation. Some measurements reached as high as 3,000.
Perhaps the biggest fish kill tied to the burn scars came on Trout Creek at the beginning of August 2014, when a hillside gave way following a rainstorm.
Rust heard of the fish kill and went to take samples.
“It looked like taking samples from a mud puddle,” she said.
She returned to the stream last year and found newborn fish downstream from the debris flow and fouryear- olds above it, leading her to conclude that the population will come back without stocking.
Rust’s findings coincide with what anglers have found, especially on the Rio Grande.