Willow Creek Flood Assistance

Project Detailsx

Client:Matanuska-Susitna Borough

Location: Willow, AK

Year Completed:2020


> Hydrogeological Engineering
> Hydrologic and Hydraulic Engineering
> Cost Estimating
> Permitting
> Public Involvement


Project Overview x

On December 21, 2019, an ice jam caused Willow Creek to flood near the Getts Bridge and Michelle Drive in the community of Willow. The ice jam causing the flood began approximately 150 feet downstream of the bridge and extended nearly 1,000 feet upstream. The jam caused the water level to increase and overflow its banks on both the north and south side of the channel, within the floodplain. The overflow flooded portions of Deneki Road and properties in the area. HDL provided assistance to the Matanuska-Susitna Borough (MSB) to respond to the flooding, working directly with the Emergency Management Team to mitigate further flooding and restore access to properties beyond Willow Creek.

Meanwhile, the HDL team prepared a memo to identify mitigation options and provide a recommended action to restore creek flow. HDL also coordinated with the Alaska Department of Natural Resources, Alaska Department of Fish and Game, U.S. Army Corps of Engineers, and MSB Floodplain Management to obtain permits, provide cost estimates for the work, and assist with presenting the project to the MSB Assembly and the Willow Community.

The proposed and approved action was to excavate a trench in the ice jam, to eliminate out-of-bank flooding and reduce the potential for additional flooding during spring breakup. HDL observed and provided direction during the work in -30 degree temperatures. The work successfully restored flow to the main channel.