Blunn Dam, Colorado

This soil-cement slope protection and spillway construction was part of the Arvada Reservoir’s Blunn Dam Enlargement Project. The existing dam was aging, showing distress and needed enlarging. work consisted of furnishing and placing approximately 21,000 cy of soil-cement for the spillway liner, the buried cutoff wall and the stair-step spillway sides. The spillway consisted of an apron 3’ (3 x 1’ lifts) in depth and 7’ (7 x 1’ lifts) high stair-stepped sidewalls. The cutoff wall was 30’ high and 340′ in length.

With the project starting in January, the soil-cement had to be placed during the winter months. Access to the dam was difficult, so the plant was located near the site and trammed to the placement site by wheel loaders. This allowed IHC access to the work area in all types of winter weather conditions. To achieve strength and density during winter conditions, the aggregate stockpiles were covered and insulated, a boiler was provided to heat the mix water and the product was cured with a white membrane cure and covered with insulating blankets to protect the product from freezing conditions.

The project was successfully completed within the contract timeframe, and the City was able to re-fill the dam on schedule.