In order to divert water around the construction site of the to-be-built dam, an outlet works and glory hole had to be designed and built. The outlet tunnel, 1700 feet long and 15 feet in diameter, was cut into stable rock on the west side of the dam. The inlet structure houses a 15-foot six-inch fixed-wheel gate mounted horizontally.
The glory hole, at elevation 9017 feet, leads to a 233-foot-deep shaft that bends 90 degrees from vertical to horizontal. Maximum discharge is 15,000 cubic feet per second if the lake level reaches 9025 feet. The outlet tunnel is lined with heavy timbering, concrete and grout.
The contractors developed a unique design for the glory hole. The trademark fins are designed to prevent any whirlpool action of the water when it enters the glory hole. Swirling water would quickly erode the concrete. A plastic model was built and tested at the Colorado State University Hydraulic Lab before construction and installation began on site
Directions: Unfortunately, the Dillon Dam Glory Hole is no longer visible, since it lies beneath the waters of Lake Dillon. Its location may be observed, however, by driving east from Frisco to Dillon on the Dam Road. The Glory Hole lies beneath the waters on the western side of the dam. Several hundred yards before the dam, a parking area is available that includes an excellent picture display and explanation of the dam construction.