Sand Creek Drop Structure

The City of Colorado Springs, Colorado, required the repair of the Sand Creek drop structure for approval of the adjacent multifamily development, the Cottages at South Murray. The Sand Creek drop structure is part of the Sand Creek channel, one of two large channels running through Colorado Springs and into a downstream flowline to Pueblo, Colorado.

The rebuilding of the drop structure is part of the City of Colorado Springs’ intergovernmental agreement with the City of Pueblo to repair failing infrastructure, reduce sediment generation, and improve water quality. When restored, it will prevent sediment load from going to Pueblo and the nearby roadway from falling out due to erosion.

Galloway’s civil engineering and water resources teams were presented with the challenge of having no history provided on how the existing failing drop structure was designed or who constructed it. After careful analysis, Galloway’s teams concluded that during the channel’s natural cycle of steepening and flattening to stabilize while handling sediment loads, the channel downstream of the drop structure flattened itself to a new stable slope. This left the elevation of the channel lower than the drop structure, causing it to fail.

The design for successfully rebuilding the structure in the 80-foot-wide channel required flattening the slope for stability and reinforcing the drop structure by staking three-foot boulders.