<P> The Great Flood of 1862 was the worst flood that the Central Valley has experienced in recorded history, flooding most of the valley and putting some places as much as 20 feet under water . </P> <P> Major public works projects beginning in the 1930s sought to reduce the amount of snowmelt flooding by the building of large dams . In 2003, it was determined that Sacramento had both the least protection against and nearly the highest risk of flooding . Congress then granted a $220 million loan for upgrades in Sacramento County . Other counties in the valley that face flooding often are Yuba, Stanislaus, and San Joaquin . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2017) (Learn how and when to remove this template message) </Td> </Tr>

What is the climate of the valley region