Owner: Denver Water
Ballard Marine Construction was contracted to install a Speece Cone oxygenation system including mechanical assembly in the Marston Reservoir for Denver Water. The reservoir, constructed over 110 years ago stores 250 million gallons per day of water diverted from the South Platte River and piped 12 miles (19km) to the site with ultimate final treatment at the Marston Water Treatment Plant. The reservoir’s 66ft (22m) depth results in a thin hypolimnion which becomes anoxic after stratification from June through September of each year. After 15 years of in depth studies the Speece Cone was selected to resolve the issue.
The marine construction portion for Ballard consisted of underwater excavation utilizing hydraulic submersible jetting and diver assisted dredging to hardpan surfaces at precise elevations, placement of three tiered rock base, monitoring settlement of the rock base, underwater forming and placement of the Speece Cone and all ancillary mechanical piping onto the underwater concrete tremie slab. The Ballard team also fused, tested and installed 1500ft (500m) of HDPE Oxygen line and 1500ft (500m) of electrical cable from the beach to the underwater Speece cone.