A unique temperature control device weighing over 8,000 tons and valued at US $80 million was installed in 1996 on the upstream face of California's Shasta Dam. It's purpose is to release the water at three levels (to a maximum depth of 350 feet) so that the water temperature is suitable for fish spawning downstream. The contract award was largely based on the merit of the erection scheme that Somerset conceived. Large temporary frames, cantilevered off the dam and supporting the five main structures were utilized to lower the permanent towers by jacks and rods until the whole weight, totaling as much as 1,200 tons per tower, was suspended. The towers were then attached to the dam by divers working 27 days at a time in saturation.