Lost Creek Reservoir in Morgan County is empty while it undergoes extensive work to make its 220-foot-high earthen dam more earthquake resistant.
Weber Basin Water Conservancy District manager Ivan Flint said the $14 million joint project involves the Bureau of Reclamation.The reservoir, built in 1964, supplies water to the Weber Basin system, which provides culinary and irrigation water to Davis, Weber, Morgan, Summit and Box Elder counties. It holds some 22,500 acre feet of water, about half the capacity of East Canyon Reservoir or two and a half times as much as the Smith and Morehouse Reservoir.
"You'll never see the dam like this again," Flint said.
Lost Creek Reservoir is located 40 miles northeast of Salt Lake City. It is northeast of Devils Slide and Croydon and is accessible by a 15-mile paved road off I-84 in Weber Canyon.
Flint said Lost Creek was identified as a quake risk a few years ago during a federal program. It was drained in 1996 and extensively tested. The biggest concern was that some sand in the dam could liquefy during a strong earthquake.
Lost Creek was drained again last year. Some 30 feet of silt was removed from the reservoir and a 36-inch drain pipe added. Preparations were also made for this year's work. A 50-foot berm in front of the dam was also built to keep the work project area dry and separate.
The reservoir was partially filled last spring and was still able to provide water most of the summer to irrigators in the area.
It has now been excavated down to the liquefiable sands, which are being compacted by a 30-ton hammer that drops from a height of 104 feet.
Once compaction is complete, more material will be added to both sides of the dam to make it thicker.
Work is expected to be completed by Christmas - weather permitting - so the dam can be filled by next spring.