Willow Creek Flooding

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, the Willow Creek near the Getts Bridge and Michelle Drive in the Willow community flooded due to an ice jam that began approximately 150 feet downstream of the bridge and extended almost 1,000 feet upstream. This resulted in an increase in water level, causing it to overflow its banks on both sides of the channel, flooding portions of Deneki Road and nearby properties. To respond to the flooding and restore access to affected properties beyond Willow Creek, HDL worked directly with the Matanuska-Susitna Borough’s Emergency Management Team to provide assistance.

Concurrently, HDL prepared a memo identifying various mitigation options and recommended actions to restore creek flow. The team also collaborated with the Alaska Department of Natural Resources, Alaska Department of Fish and Game, U.S. Army Corps of Engineers, and MSB Floodplain Management to secure necessary permits, estimate the costs, and present the project to the MSB Assembly and the Willow Community.

The selected course of action was to excavate a trench in the ice jam to prevent out-of-bank flooding and minimize the risk of additional flooding during spring break-up. Despite extreme weather conditions of -30 degrees, HDL provided direction and closely monitored the work, resulting in a successful restoration of flow to the main channel.