Fish Passage Opportunities and Lessons Post-2013 Colorado Floods

In September 2013, a stalled cold front over Colorado collided with warm, monsoonal air from the south, causing persistent, heavy rains and exceeding 17 inches in Boulder County alone.  Rapid runoff from the steep, impenetrable terrain of the mountains and foothills, along with ground saturation and overland flow in urban areas led to extensive flooding along a stretch of almost 200 miles from north to south in the Front Range in Colorado.  Eight deaths were reported, ~11,000 people were evacuated and earthen dams burst. The flooding caused tremendous damage to buildings, roads, and utilities, and changed the landscape through erosion, sediment transport, and deposition.  Also damaged in the flooding events were diversion dams that irrigate approximately 720,000 acres of land.  The U.S. Fish and Wildlife Service, in cooperation with Boulder County and Trout Unlimited have used the flooding events as opportunities to work collaboratively with diversion dam owners and operators to retrofit their structures to be “fish friendly”.  These projects have a dual purpose; to provide decreed water but to provide for fish passage as well.  These projects pair nontraditional partners to find innovative approaches to providing fish passage in streams that still harbor a struggling native fish community.