Lake Hennessey
Encyclopedia
Lake Hennessey is a man-made lake in the hills east of St. Helena
, California
, U.S.A.
.
The lake 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 (91.4 cm) 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 dam did not include a way to drain water from the reservoir when it comes close to full capacity. Once the lake is full, water drains from a spillway causing potenital flooding dangers downstream. The reservoir and pipelines are maintained by Napa and it is the primary source of water for the city. When the reservoir reaches its capacity, outflow reaches San Pablo Bay
by way of Conn Creek which feeds the Napa River
. The lake was named after Edwin R. Hennessey. Hennessey was a local civic leader who played a role in the development of the Conn Valley reservoir.
.
St. Helena, California
St. Helena is a city in Napa County, California, United States. It is part of the northern San Francisco Bay Area. The population was 5,814 at the 2010 census....
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, U.S.A.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
The lake is formed by Conn Creek Dam, built in 1948 across Conn Creek. Construction of the earthen dam was authorized by the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
when it passed the Flood Control Act of 1944
Flood Control Act of 1944
The Pick-Sloan Flood Control Act of 1944 , enacted in the 2nd session of the 78th Congress, is U.S. legislation that authorized the construction of numerous dams and modifications to previously existing dams, as well as levees across the United States...
in order to mitigate flooding downstream in Napa, California
Napa, California
-History:The name Napa was probably derived from the name given to a southern Nappan village whose people shared the area with elk, deer, grizzlies and cougars for many centuries, according to Napa historian Kami Santiago. At the time of the first recorded exploration into Napa Valley in 1823, the...
. 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 (91.4 cm) 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
Basalt Rock Company
Basalt Rock Company was a multifaceted industrial operation that was founded in 1920. The company started as a rock quarrying operation located a few miles south of Napa, California near the Napa River. It later branched out into the ship building business in 1941 when it started building ships...
plant located south of Napa. The design of the dam did not include a way to drain water from the reservoir when it comes close to full capacity. Once the lake is full, water drains from a spillway causing potenital flooding dangers downstream. The reservoir and pipelines are maintained by Napa and it is the primary source of water for the city. When the reservoir reaches its capacity, outflow reaches San Pablo Bay
San Pablo Bay
San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in northern California in the United States. Most of the Bay is shallow; however, there is a deep water channel approximately in mid bay, which allows access to Sacramento, Stockton, Benicia, Martinez, and...
by way of Conn Creek which feeds the Napa River
Napa River
The Napa River, approximately 55 miles long, is a river in the U.S. state of California. It drains a famous wine-growing region, called the Napa Valley, in the mountains northeast of San Francisco. Milliken Creek is a tributary of the Napa River....
. The lake was named after Edwin R. Hennessey. Hennessey was a local civic leader who played a role in the development of the Conn Valley reservoir.
Conn Creek Dam
Conn Creek Dam is an earthen dam 125 feet (38.1 m) high and 700 feet (213.4 m) long containing 500000 cubic yards (382,277.4 m³) of material. Its crest is 330 feet (100.6 m) above sea level. It is owned by the City of NapaNapa, California
-History:The name Napa was probably derived from the name given to a southern Nappan village whose people shared the area with elk, deer, grizzlies and cougars for many centuries, according to Napa historian Kami Santiago. At the time of the first recorded exploration into Napa Valley in 1823, the...
.