Winsor Dam on Santa Clara Creek



on the Santa Clara River/Creek


HAER No. UT-96. Pages 2-3
A major flood in 2011 badly damaged the dam once again and prompted the Shem Dam Rehabilitation Project, sponsored by the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS), under the authority of the Emergency Watershed Protection program. In accordance with the National Environmental Protection Act and the National Historic Preservation Act, the NRCS developed a historic properties treatment plan to mitigate the adverse effects of the rehabilitation project on Shem Dam. The mitigative measures specified in the treatment plan included documentation of the dam for inclusion in the Historic American Engineering Record.
The Shem Dam Rehabilitation Project was undertaken by the NRCS in cooperation with Washington County and the Shivwits Band of Paiutes. In March of 2014, the Utah State Historic Preservation Office (SHPO) reviewed and accepted the historic properties treatment plan prepared by the NRCS. In 2013, an archaeological inventory of the Shem Dam site was carried out by NRCS Cultural Resources Specialist Tara S. Hoffman, under the supervision of NRCS State Cultural Resources Specialist Andrew Williamson. Hoffman conducted historical research on the dam at the libraries of Utah State University, Weber State University, and Southern Utah University; she also consulted several online databases for relevant documents. In 2014, the NRCS hired William Self Associates, Inc. (WSA), to carry out additional historical research and additional field documentation of the dam, including preparation of Historic American Engineering Record (HAER) documentation. WSA’s Scott O’Mack, based in Tucson, Arizona, carried out additional research at the Utah Division of State History in Salt Lake City, the office of the Washington County Recorder in St. George, and the Dixie State University Library, Special Collections, in St. George. O’Mack also completed additional field documentation of the dam, assisted by WSA archaeologist John Curry. O’Mack and Curry collected data for measured drawings using a Leica TCR407 total station and a Trimble GeoXT handheld GPS unit. Jimmy Mack, WSA GIS specialist, processed the data, and Lindsay Wygant, WSA graphics specialist, created the measured drawings. Large-format black-and-white photographs of Shem Dam were taken by Roger Whitacre of Denver, Colorado, on January 29–30, 2015, a few days before the rehabilitation project began. Color digital photographs of the dam and associated features were taken by Hoffman during the 2013 fieldwork and by O’Mack and Curry during the 2015 fieldwork.
Historic photographs of Shem Dam are reproduced here with the permission of the libraries of Utah State University, Weber State University, and Southern Utah University. Photographic reproductions of the original construction drawings of Shem Dam are used here with the permission of the Dixie State University Library. HAER No. UT-96, Pages 30-31
At the time of the current HAER documentation, Shem Dam and the adjacent portions of the Santa Clara River streambed had been recently cleared of dense vegetation in anticipation of construction for the Shem Dam Rehabilitation Project. The area immediately upstream of the dam was long ago filled with silt and is level with the intact crest of the spillway, which means the upstream faces of the spillway and abutments are mostly obscured below the level of the spillway crest. To route the minimal seasonal flow of the river away from the spillway, which is 88 See note 70 above. the focus of the current repairs, the construction crew excavated ditches in the accumulated silt leading to the dam’s diversion tunnel, including a deep ditch along the north bank of the river. The diversion tunnel gate was then raised, using the existing gear lift, to allow the flow to pass through the dam.




Historic American Engineering Record, Shem Dam (Winsor Dam), HAER No. UT-96
Prepared by Scott O'Mack, William Self Associates, Inc.,
    for the USDA Natural Resources Conservation Service (NRCS)
March 2016, 96 Pages (see pp. 2-3, 30-31)
[Large file, so this may take a while to load]

Draft Environmental Assessment (EA) for the Rehabilitation of Shem Dam
Prepared by McMillen, LLC for the USDA Natural Resources Conservation Service (NRCS)
January 2014, 292 Pages
[Large file, so this may take a while to load]

Cultural Resources Inventory of the Shem Dam Rehabilitation Emergency Watershed Protection Project
Prepared by Tara S. Hoffman for the USDA Natural Resources Conservation Service