COLORADO SPRINGS, CO – The Waldo Canyon Fire in June 2012 was one of the most destructive fires in Colorado history. The fire roared into neighborhoods killing two people, demolishing 346 homes and destroying over 18,000 acres of vegetation in the Pike National Forest and in Colorado Springs.
Because of the severe burn scar, the City of Colorado Springs needed to take action to lessen future damage from post-fire flooding. “Since there was no vegetation left after the fire to absorb rainfall and hold back debris and rocks from coming down with the floodwater, we began a project to mitigate the issue,” said Tim Mitros, stormwater manager for Colorado Springs.
“Massive damage to homes, bridges, culverts and streets in Colorado Springs, Manitou Springs and even further downstream would likely occur if nothing was done to slow down the impending avalanche of debris,” said Mitros. “Protecting everyone in the area was a priority.”
City engineers were particularly concerned about the historic Glen Eyrie Castle. The English Tudor-style castle was built by General William Jackson Palmer, the founder of Colorado Springs, and is listed on the National Registry of Historic Places. The 800-acre estate is now a conference and retreat center. In case of floods, the castle would be directly impacted by any debris coming down the channel from the canyon.
Consultants determined that a net should be installed to hold back debris that could damage the castle. Two giant metal flexible nets were designed to catch boulders and trees that could be swept down the mountain during flooding. The two flexible nets consisted of two parts. The lower section was designed to catch the smaller debris. The upper section, a 21-foot by 80-foot net, was installed in a ravine along Camp Creek to protect Glen Eyrie Castle and to keep waste from rushing downstream into the homes along 30th Street in western Colorado Springs. City workers clean the debris from the net after any major storm.
“The net was installed in the fall of 2012 soon after the fire because we knew they were going to have problems,” said Mitros.
“The installation was a two-to-three month process.”
The cost of the project was $700,000 and was funded by the Natural Resources Conservation Service.
In July 2013, during flash flooding, the nets caught about eight feet of mud, sediment and logs preventing the flow from plunging into homes and businesses downstream.
After the September 2013 flood, Mitros says that the nets “did what they were supposed to do,” holding back some of the larger debris. Nevertheless, their main purpose is to protect the area during flash flooding, a more frequent occurrence, and it became clear that further mitigation efforts would be needed for a sustained rainfall.
None of the buildings at Glen Eyrie were significantly damaged, but other mitigation is being considered.