Jul 17, 2014 6:08 PM by Zach Thaxton
Stormwater bosses for the City of Colorado Springs are claiming success following this week's storms that produced flash flooding. Multi-million dollar debris catch basins and backup flood mitigation measures in the Mountain Shadows neighborhood did their jobs in preventing major debris flows into the streets and drainage canals on Colorado Springs' west side.
"This is a huge success story," said Aaron Winter, Executive Director of the Flying W Ranch. "You never really know how they're going to react until you actually get that heavy rain event." A catchment facility on the north side of the Flying W Ranch property along North Douglas Creek filled to the brim with water, mud, and debris during Wednesday's torrential rains, but the newly-finished basin successfully retained the mud and debris while only water flowed over its earthen dam. The debris-free water was then slowed and dispersed by an alluvial fan, lessening its force as it entered the concrete channels that steer North Douglas Creek through subdivisions such as Reed Ranch. "If these basins had not been in place, those city storm drains would have filled up with sediment, and that would have automatically had a lot more flooding going in through Reed Ranch and Mountain Shadows, and what you saw (Wednesday) probably would have been 100 times worse," Winter said.
A catchment facility further south was less successful in holding back mud and debris, but a backup flood-control system prevented the flooding from penetrating the Alpine Autism Center. "The water brought down a whole bunch of organic material that blocked the inlet and our emergency overflow on it, so then it came over the top of the dam," said city Stormwater Manager Tim Mitros. The material that overflowed the dam then rushed toward the Autism Center, but was successfully blocked and steered away by huge sand-filled TrapBags, standing about 5 feet tall. "It didn't get into the Autism Center," Mitros said. "It diverted around to the north of it, into the parking lot, and then into our streets system."
The challenge now is to clear the basins of debris before the next round of storms. Winter says the basin in Flying W Ranch filled with nearly 1,000 dump truck loads of sediment and debris during Wednesday's storms. Crews were using an excavator Wednesday afternoon to clear the intake of the basin behind the Autism Center.