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Ralston Creek Flood Risk Management Project, Arvada, CO

Project Name: Ralston Creek, Arvada, Colorado Flood Risk Management Study
Location: Arvada, Colorado
Authority: Section 205 of the Flood Control Act of 1948, as amended
Sponsor: City of Arvada
Current Phase: Feasibility

The city of Arvada (non-federal sponsor) has partnered with the U.S. Army Corps of Engineers (Omaha District) on a study to evaluate possible flood risk management solutions along Ralston Creek, a tributary of Clear Creek. The project area for this study is a 3.5-mile segment of Ralston Creek from Beech Street (upstream project area limit) to the Van Bibber Creek confluence (downstream project area limit) within Arvada, Colorado.

Like most communities in the foothills of the Rocky Mountains, Arvada’s typical flood threat is flash flooding. Major urban development in the Ralston Creek watershed in the past 40 years has increased the threat of flash floods. The nature of Ralston Creek within the project area as an urbanized stream presents flood risk problems for residents of Arvada including damages to infrastructure and threats to human health and public safety. 

The largest rainfall event to fall in the Ralston Creek watershed in recent history occurred over a 36-hour period in mid-September 2013. Unlike typical summer thunderstorms, this rainfall was widespread across the watershed and abnormally long in duration. Damages were reported on Ralston Creek including (1) water supply monitoring equipment destroyed at both Ralston Reservoir and Arvada/Blunn Reservoir, (2) inflow channels were eroded, (3) city water treatment plants had problems with turbid water, (4) roadways were overtopped and houses were damaged, and (5) stormwater and canal flows were commingled and canal embankments were breached.

The purpose of the Ralston Creek feasibility study is to identify the potential for developing flood risk management solutions, which could be structural and/or nonstructural, that are beneficial to the public, economically viable, and environmentally acceptable.

Project Update: The U.S. Army Corps of Engineers, in cooperation with the City of Arvada and the Urban Drainage and Flood Control District, held an open house on Tuesday, September 12 at the Arvada City Hall to gather public input on preliminary alternatives currently being evaluated to reduce flood risk and improve public safety along approximately 3.5 miles of Ralston Creek within the city limits of Arvada.