The Colorado Department of Transportation said accumulated debris and sediment from previous storms may have played a bigger role than rain in last weekend's flash flood on U.S. 24 in Ute Pass.
The flood overwhelmed a flood control project below Wellington Gulch, across from the Eagle's Nest Wellness Center. The flood closed the highway and backed up traffic for four hours.
The project was built after a similar flood in the summer of 2012, shortly after the Waldo Canyon Fire. The area hadn't flooded since then.
Dave Watt, a CDOT engineer, said the Wellington Gulch project -- and others in Ute Pass -- include a system of retention ponds and catchment nets to trap debris and allow runoff to flow smoothly.
The accumulated debris apparently caused runoff to build until it burst through as a flash flood, he said.
"We need to clean (ponds and nets) out after rain events when they fill up or when they become clogged," Watt said. "That's what we've been doing, and we need to continue to do it. It does take a little bit of time to do that effort. It takes time and equipment."
Watt said except for a new debris basin above Waldo Canyon expected to be completed later this month, CDOT has no plans to build other flood control projects.
CDOT has spend $6 million on completed projects and another $4 million on projects that are nearing completion, he said.
"The fire changed that area forever," Watt said. "We have more debris, sediment and runoff coming down on the highway than we've ever had before. We have to plan how to handle it."
Watt said although many people describe the recent flood as a mudslide, he said that description is incorrect and the event was a flash flood containing debris and sediment.
"I know that's splitting hairs to some people," he said.