Sand Creek and Platte Grade Control Structure

This location on Sand Creek was already budgeted to receive Stormwater Enterprise funding in 2008 for an emergency capital improvement project. Unfortunately, before the materials arrived for the project, an August 25, 2008 storm partially washed out the damaged drop structure. Emergency repairs were done to protect an exposed gas line and other infrastructure, however the record rainfall on Sept. 11, 2008 washed out those repairs and the rest of the drop structure. Without the drop structure to control the grade, the creek bed dropped another 10 to 15 feet in spots as Sand Creek experienced record runoff amounts Sept. 11 and 12. This damage necessitated the closure of the Platte Avenue bridges over Sand Creek over the Sept. 12-14 weekend. Stormwater maintenance crews from the City’s Street Division worked 12-hour days over the weekend so the bridge could be reopened to traffic by Monday morning.

The permanent repairs started shortly after and were completed in January 2009. The project included the installation of metal sheets, pounded 30 feet deep to the bedrock downstream of the Platte Avenue bridges. The metal sheets serve as an impenetrable barrier that will force stream flows over the sloping grouted boulder drop structure. The drop structure will help stabilize Sand Creek and protect the Platte Avenue bridges and nearby utility crossings from future erosion due to heavy stream flows.

In addition to the wall, the sides of the creek have been reinforced with large boulders called riprap. This will help protect sanitary sewer lines that run along the banks of the creek.

Stormwater Enterprise Funding:       $650,000

Platte Bridge at Sand Creek - Completed

Damage to Platte Bridge at Sand Creek