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Lake Hennessey

Lake in Coast Ranges near Yountville, CA

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Lake Hennessey is a reservoir in the Vaca Mountains, east of St. Helena and the Napa Valley, within Napa County, California. The reservoir is formed by Conn Creek Dam, built in 1948 across Conn Creek. Construction of the earthen dam was authorized by the United States Congress when it passed the Flood Control Act of 1944 in order to mitigate flooding downstream in Napa, California. Funding for the dam was never appropriated by Congress, so in 1946 the City of Napa took on the project and built it at a cost of $550,000 dollars plus $250,000 for the land. The cost of laying the 36 inches (910 mm) diameter pipeline from the dam to the city of Napa was $1.7 million. The 30 miles of pipe for the project was manufactured at the Basalt Rock Company plant located south of Napa. The design of the…

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Lake