Shem Dam, Along Santa Clara River on west side of County Road 3184, 0.9 miles north of intersection with Old Highway 91, Ivins, Washington County, UT

Significance: Shem Dam was built in 1934–35 by the Civilian Conservation Corps (CCC) as a project sponsored by the U.S. Forest Service, Dixie National Forest. The dam was designed by two Utah engineers: Luther M. Winsor, an irrigation and flood-control specialist with the U.S. Department of Agriculture, Bureau of Agricultural Engineering, who was assigned to design and oversee Forest Service flood-control projects in Utah; and Leo A. Snow, an engineer and surveyor from nearby St. George, Utah. The dam is an embankment of rubble masonry with a rock and earth fill. It has two large abutments that stand perpendicular to the channel of the Santa Clara River and are linked by a central-arch spillway. The dam has a maximum height of 38' and an overall length of approximately 375', which made it one of the largest dams built by the CCC in Utah. In addition to serving as a flood-control structure on the Santa Clara River, Shem Dam diverted irrigation water to fields downstream on the Santa Clara Bench, cultivated by residents of the communities of Ivins, Santa Clara, and St. George. A diversion below the dam also routed irrigation water to lands cultivated by the residents of the Shivwits Indian Reservation.
Unprocessed Field note material exists for this structure: N1671
Survey number: HAER UT-96
Building/structure dates: 1934-1935 Initial Construction
Building/structure dates: 1939 Subsequent Work
Building/structure dates: 1958 Subsequent Work
Building/structure dates: after 2011 Subsequent Work