Last month, construction began on the saddle dam, a 40-foot-tall clay core dam that sits at the south end of Chimney Hollow Reservoir. Although there was not enough clay in the Chimney Hollow valley to build the main dam, there was more than enough to build this smaller dam. The clay core is 30 feet wide at the base and tapers to 10 feet wide at the top with rock fill on either side, similar to the structure of the main dam.  

Each day, construction of the saddle dam begins with scraping the top layer of clay, and then placing nine-inch loose lifts of additional clay. These lifts are then compacted to 4 or 5 inches and in the meantime, the rock fill is added. Sand and gravel transitions are compacted on each side of the clay, ultimately transitioning to the same size rock used for the shell of the main dam. About two lifts are placed daily, and the dam currently sits at 15 feet high.  

Construction is expected to be complete by fall 2024. The saddle dam will increase the storage capacity of the reservoir by 30 percent, allowing it to hold 90,000 acre-feet of water.