Denver Water - Cheesman Dam Upstream Control Project - Phase 1

Cheesman Dam is a primary reservoir for Denver Water, providing potable water to Denver and the surrounding area. Completed in 1905, built by Italian master masons using finely set and mortared granite blocks, Cheesman was a technoligical masterpiece and landmark of civil engineering for decades to come.

The Upstream Control Project, Phase 1 is the first step in the replacement of the internal gate valves with new hydraulically operated valves mounted on the upstream face of the dam. Since the bypassoutlets were tunneld through the canyon wall to ensure iht integrity of the dam, the existing opening will be enlarged to accept new stainless steel spool pieces, weighting up to 25,000 pounds will be moved just inside the stone wall and secured in place with anhcor bolts which will be drilled into the native material. Once secured in place the new spools will be grouted to provide a leak free seal. New stainless steel valves will then be mounted to the spool pieces. Once the valves are in place, new trashracks will be installed to completely protect the new vavle assembly as well as prevent large rubble from entering the intake system. These new spools and valves will be installed on the three existing intake openings.

To operate these new valves, a control structrue will be built on the crest of the dam. This new structure will house the hydraulic pump unit and the controls which will operate the valves. To connect the hydraulic tubing to the valves, holes will be drilled into the dam, exiting into the reservoir next to the gates. Hydraulic tubing will be installed into the holes and then the hole filled with grout. The hydraulic tubing will then be connected to the gate.

The work in the water will be performed by divers, operating from a barge which will be constructed on the reservoir from segmentable barge units, "flexifloats'. Onto these barges will be assembeled a complete surface diving spread. The diving on this project will be acombination of Surface supplied diving and Saturation Diving. A staging area will be constructed on the shore of the reservoir to load all of the equipment and materials onto the barge and support the operation during construction.

An ROV will be used to assist with the initial surveying of the site. Thedata will be used in the design and fabrication of purpose built tooling to assist with the removal of the existing to to enlarge the existing opening to allow room for the new spool pieces. Fixtures will also be needed to move the spools in and assist with the rock drilling required for the anchoring.