The City of Fort Collins, Colorado, is preparing for the construction of the Michigan Ditch Tunnel Project, which will help protect a vital water source high in the mountains west of Fort Collins. Currently, a key segment of the water supply system moves through an open channel that has been damaged numerous times by a very large landslide. As a result, Fort Collins Utilities is putting this segment in a hard-rock tunnel that is to be mined this summer.
The $8.5 million project consists of 800 ft of 98-in. OD rib-and-board tunnel with 60-in. Hobas pipe as the final carrier. The custom-built Akkerman TBM is expected to launch in June with the project completed by October 2016, in time for the spring runoff in 2017. The construction window for this project is extremely short due to the high elevation of the site (10,500 ft) and deep snow pack related to late spring and early fall snows.
During the design phase of the project, the design team conducted three horizontal rock cores to characterize the ground conditions. The tunnel will be mined through highly faulted metamorphic and igneous rocks that are highly fractured. The project is being delivered through Fort Collins Utilities’ Alternative Product Delivery Method (APDS), a unique delivery method which brings the owner, designer and contractor together from the very start of the project all the way through the end of construction. APDS has been proven to build better projects that are completed on schedule and budget without any claims.