Flash flood waters roiled off the southern slopes of the Waldo Canyon burn scar, damaging homes, cars and even killing a man near Manitou Springs, but Colorado Springs Utilities officials have called themselves fortunate.
Waters that spill down from the burn area through pipelines and into water treatment facilities on the U.S. Air Force Academy campus north of Colorado Springs have had minimal effect since mitigation work began in the fall of 2012. The Pine Valley and McCullough plants at the academy supply water to about 200,000 people, CSU source water protection project manager Kim Gortz said.
Gortz and other utilities officials were in the Pike National Forest above the treatment plants Thursday, talking about the mitigation work.
Gortz said rains that sent flash floods into Manitou Springs July 30, 2012 less than a month after the fire provided a "wake-up call for utilities." That storm created gullies in the Northfield Gulch watershed and damaged a backup pipeline out of Rampart Reservoir, costing CSU more than $1 million to repair.
Utilities quickly teamed with the U.S. Forest Service and began creating sediment retention ponds, laying log sills, seeding and mulching steep slopes, and reshaping channels in hopes of slowing flows from the ash-laden ground and saving important infrastructure.
"This whole area was ripe for more gully washes," Gortz said Thursday while standing in a valley along Northfield Gulch that had a deep trench dug by rainwater last fall.
Dana Butler, a U.S. Forest Service hydrologist, showed off a valley that showed no signs of washout on Thursday. The area's re-vegetation was obvious. Butler pointed to signs of buried logs that were installed in late 2012 to slow and spread the flow of rainwater. Willow branches were been planted in the 120-foot-wide valley and are expected to grow quickly.
"There's not a fix when you have a burn area," Butler said Thursday while standing just feet from a pair of sediment retention ponds. "You just have to lessen the impact the best you can. Downstream we're actually raising the water table. That will encourage vegetation growth."
Colorado Springs Utilities has spent $3.5 million in the Northfield Gulch watershed, using special-use permits to do work on public land. But ratepayers haven't carried the entire burden. Gortz said CSU has already been reimbursed about $1.5 million from the National Resources Conservation Service as part of the Emergency Watershed Protection program.
Workers from the Forest Service, the Coalition from the Upper South Platte and many volunteers from other groups have helped and contributed hours to CSU's 25 percent match obligation under EWP rules.
An army of volunteers were working on utilities projects Thursday. Many were raking steep slopes near the top of the watershed and planting seeds to help re-vegetate and reduce rain impact.
"This work would not be successful without hand crews and volunteers," Butler said.