Mountain Dell Dam

The Mountain Dell Dam provides a water equalizing and storage reservoir for Salt Lake City, Utah located 10mi east of the city in northeastern Salt Lake County, near Interstate 80 in Parley's Canyon.Designed by John S. Eastwood, and constructed between 1914 and 1925, the dam is an example of a mixed buttress dam and multiple arch dam construction. At the time the plans were made, the city was in need of a sufficient supply of water, especially during late summer and the middle of winter.With the completion of the dam, the city had an available storage capacity of 850e6USgal, and distributing or equalizing capacity of 24e6USgal compared to 9e6USgal previously.The dam was listed on the National Register of Historic Places in 1980.DesignPlans were made for three types of dam: Arched solid dam, gravity type Reinforced concrete dam of the Ambursen type Multiple arch reinforced concrete dam of the Eastwood design After consideration, the multiple arch type was chosen. One of the factors influencing this decision was the bedrock condition at the site. The bedrock is a calcareous shale not entirely watertight and of a nature to decompose somewhat under exposure to air and water. The advantages of the multiple arch type in this connection were considered to be the practical elimination of upward pressure, the practical impossibility of overturning or sliding on its base and the ready facilities for internal inspection of the dam at any time.