The California Department of Water Resources (DWR) is part of the California Natural Resources Agency and is responsible for the management and regulation of the State of California's water usage. The department was created in 1956 by Governor Goodwin Knight following severe flooding across Northern California in 1955, where they combined the Division of Water Resources of the Department of Public Works with the State Engineer's Office, the Water Project Authority, and the State Water Resources Board. It is headquartered in Sacramento.
History
1850-1875
California recognizes many types of water rights. Prior to the Treaty of Guadalupe Hidalgo, signed in 1848, California was part of Mexico. Riparian rights were the most prevalent type of water right. Under riparian rights, which have their origins in Roman law, a landowner can use water flowing by his property for use on his property. When California became part of the United States, the United States agreed to recognize existing law. Pueblo rights were the only vested water rights at the time. Pueblo rights provided that Spanish and Mexican pueblos were entitled to the paramount beneficial use of all needed naturally occurring water from the entire watershed of a stream flowing through the pueblo.

When gold was discovered in 1848, immigrants from all over the world came to California. During the California Gold Rush, gold miners would divert large quantities of water from rivers and streams for hydraulic mining. Local custom dictated how water was shared in mining camps, but in general, the miners followed the same practice in allocating water as they did in staking their mineral claims. In its earliest form, an appropriative water right was created simply by taking water and putting it to beneficial use. However, to "state a claim" miners would often post a notice to others that they were taking and using water. Soon after California became a U.S. state in 1850, the first session of the California State Legislature immediately adopted laws to deal with the state's water. This included the adoption of the English common law system, which also included the doctrine of riparian rights, although this system was better suited to the water-rich eastern United States. Shortly thereafter, Californian courts recognized appropriative water rights.

Because of these plural systems of water allocation, disputes soon ensued; these differences were resolved by the state courts. In 1872, the Legislature adopted a procedure in the Civil Code to provide a method for those claiming an appropriative water right to record their claims with the county recorder of each county. In 1886, the courts addressed competing claims between riparians and appropriators in the case of "Lux v. Haggin." However, within 25 years, excessive claims to water rights threatened to affect economic development in the state. In response, the governor formed a Water Commission to make recommendations regarding California's water law. In 1913, Californian voters adopted by referendum the Water Commission Act, which created the state Water Commission and set forth an administrative procedure for acquiring an appropriative right.

In 1926, the courts held that a riparian water user was entitled to the full flow of a stream, without regard to the reasonableness of the use. In response, in 1928, the California Constitution was amended to require that all water use in California be reasonable and beneficial. (Article X, Section 2).
1875–1900
In 1878, William Hammond Hall of the Office of State Engineer conducted a series of investigations in California's Central Valley and drafted a series of plans calling for various publicly funded and owned irrigation projects. Hall's study was accomplished on a budget of $100,000. The Central Valley continued to grow in the absence of a state-run project, yet Central Valley landowners and coastal cities (including San Francisco) managed to acquire water rights in the Sierra Nevada mountain range for use in the valley.





