Critical spring moisture has slowed progress of the watershed restoration team on the High Park Fire, but not that of Mother Nature.
“The low and moderately burned areas look like they are coming back very well,” said John Andrews, conservation engineer with the Natural Resources Conservation Service. “The high-severity areas are the ones that haven’t really changed, and they are the ones on which we are concentrating treatments.”
Native, and mostly natural, grass regeneration is making great use of the spring moisture in much of the low and moderate burn intensity areas, which account for about 80 percent of the total 87,487 acres burned. But that same snowpack has also slowed a reassessment of where restoration needs a helping hand, which is now expected to be completed in mid-June.
“The conclusion of our team was because of the late spring we just couldn’t make a call yet,” said Andrews, noting the added moisture surely is paying dividends in aiding overall soil cover. “We need to go out there in another two to three weeks and make that assessment.”
But previous efforts appear to be working. The emergency watershed restoration team, led by the cities of Fort Collins and Greeley, Larimer County, the U.S. Forest Service and the National Reclamation and Conservation Service, completed almost 4,000 acres of mulching in the most vulnerable areas to erosion, in moderate and severe burn areas with slopes between 20 and 60 percent, as well as areas presenting an immediate hazard to life and property.
Larimer County fire recovery manager Suzanne Bassinger said remote sensing updates are also needed, and will probably be flown in early June using LIDAR, aerial photography that is aided by laser, resulting in three-dimensional data and insight into slope and aspect.
Bassinger said the team only had about $1 million in federal funds to spend on watershed protection last year, but spending by local governments allowed approximately 3,000 acres of private property to be treated with wood mulch, at a cost of between $1,000 and $1,200 per acre. On Forest Service land, about 881 acres were mulched with shredded wood, with another 4,700 slated for treatment this year.
Fort Collins and Greeley, which were anxious to protect water supplies, picked up most of the tab for the private land costs. Local governments are still waiting on a check from the NRCS, awarded by Congress in April, which split $20 million in federal funds between the Waldo Canyon and High Park fires last year.
“Usually the cost share for these programs is 75 percent federal and 25 percent local,” Andrews said. “I think the work that was done last year was about the reverse.”
Anecdotal evidence held that the ash and sediment loading on the Poudre River has been significantly reduced this year, but that may not be entirely true. Fort Collins is not using any Poudre River water now that the runoff has begun, city water production manager Lisa Voytko said. Significant ash was coming off untreated slopes following two April storms, especially in the Pendergrass Creek and South Fork basins.
“The Poudre has very high turbidity (or sediment loading) — we started seeing that even before there was a significant runoff season,” Voytko said. During a normal runoff season that turbidity measurement would run as high as 15 or 20 NTU (Nephelometric Turbidity Units). This year’s runoff measurements were more than 100 NTU.
During non-runoff times, the Poudre’s turbidity drops to about 1 to 2 NTU, but it is the summer thunderstorms that may be the most difficult. Torrential rain over even limited areas of the watershed can cause more erosion than slow-melting snowpack and may stir up more sediment and ash in tributary basins and the Poudre itself that was deposited during the fire last year.
“Those summer thunderstorms are when that sediment is really going to be stirred up,” Bassinger said.
Bassinger said much of the needed reassessment centers around how much of the burn area remains resistant to water, a condition that is also referred to as hydrophobic. In the initial Burned Area Emergency Response (BAER) report, 12,238 acres were deemed hydrophobic, but that clay-like upper layer that repels water may have broken down in some areas.
And the patchy nature of the fire — which was of great consternation to firefighters, who deemed High Park a “dirty fire” — somewhat aids the reclamation efforts. The severely burned areas are interspersed among areas of lesser damage, as well as many areas that the fire did not significantly impact.
“That’s a plus because it is the huge areas (of hydrophobic soils) that really create problems,” Andrews said.
Larimer County will likely be contacting private landowners in June concerning permission needed to conduct aerial mulching. Most of the reseeding has been moved back to this fall, when it will do the most good, Andrews said.