Exploitation of groundwater
The farmers' victory over the miners in the case of hydraulic mining highlights the increasing importance of agriculture in California, which became a state in 1850. The first farmers practiced dryland farming (without irrigation) and grew mostly wheat and barley. But in the 1850s, farmers in the Central Valley began tapping into groundwater sources.
Sometimes the water existed underground at high pressure and rose to the surface on its own, in what is called an artesian well; in other cases windmills pumped the water to the surface. By 1865, many farmers had switched from dryland farming to irrigated agriculture.
The completion of the transcontinental railway in 1869 prompted some of this intensive use of groundwater. The availability of refrigerated rail cars meant that farmers in California had an incentive to grow water-intensive but lucrative fruit and other crops for winter consumption in the east.