Groundwater replenishment happens through direct recharge and in-lieu recharge. Water used for direct recharge most often comes from flood flows, water conservation, recycled water, desalination and water transfers.

California’s “Mediterranean” climate, characterized by warm, dry summers and mild winters, is considered one of its great attractions, but it also can be unpredictable with flooding followed by drought and few years of “normal” precipitation.  [See also Hydrologic Cycle].

Wastewater management in California centers on the collection, conveyance, treatment, reuse and disposal of wastewater. This process is conducted largely by public agencies, though there are also private systems in places where a publicly owned treatment plant is not feasible.

In California, wastewater treatment takes place through 100,000 miles of sanitary sewer lines and at more than 900 wastewater treatment plants that manage the roughly 4 billion gallons of wastewater generated in the state each day.

Liability for levee failure in California took a new turn after a court ruling found the state liable for hundreds of millions of dollars from the 1986 Linda Levee collapse in Yuba County. The levee failure killed two people and destroyed or damaged about 3,000 homes.

The collapse also had long-term legal ramifications.

The Paterno Decision

California’s Supreme Court found that, “when a public entity operates a flood management system built by someone else, it accepts liability as if it had planned and built the system itself.”

The federal Safe Drinking Water Act sets standards for drinking water quality in the United States.

Launched in 1974 and administered by the U.S. Environmental Protection Agency, the Safe Drinking Water Act oversees states, communities, and water suppliers who implement the drinking water standards at the local level.

The act’s regulations apply to every public water system in the United States but do not include private wells serving less than 25 people.

According to the EPA, there are more than 160,000 public water systems in the United States.

Overdraft occurs when, over a period of years, more water is pumped from a groundwater basin than is replaced from all sources – such as rainfall, irrigation water, streams fed by mountain runoff and intentional recharge. [See also Hydrologic Cycle.]

While many of its individual aquifers are not overdrafted, California as a whole uses more groundwater than is replaced.

The treatment of groundwater— the primary source of drinking water and irrigation water in many parts of the United States — varies from community to community, and even from well to well within a city depending on what contaminants the water contains.

In California, one-half of the state’s population drinks water drawn from underground sources [the remainder is provided by surface water].

California has considered, but not implemented, a comprehensive groundwater strategy many times over the last century.

One hundred years ago, the California Conservation Commission considered adding  groundwater regulation into the Water Commission Act of 1913.  After hearings were held, it was decided to leave groundwater rights out of the Water Code.

Groundwater banking is a process of diverting floodwaters or other surface water into an aquifer where it can be stored until it is needed later. In a twist of fate, the space made available by emptying some aquifers opened the door for the banking activities used so extensively today.

Recurrent droughts and uncertainties about future water supplies have led several California communities to look to treat salty water for supplemental supplies through a process known as desalination.

Desalination removes salt and other dissolved minerals from water and is one method to reclaim water for other uses. This can occur with ocean water along the coast and in the interior at spots that draw from ancient salt water deep under the surface or where groundwater has been tainted by too much salt.

1769 First permanent Spanish settlements established. Water rights established by Spanish law.

1848 Gold discovered on the American River. Treaty of Guadalupe signed, California ceded from Mexico, California republic established.

1850 California admitted to Union. Construction begins on Delta levees and channels.

1860 Legislature authorizes the formation of levee and reclamation districts.

1862  Major flood in Sacramento Valley inundates new city.

The California Environmental Quality Act, commonly known as CEQA, is foundational to the state’s environmental protection efforts. The law requires proposed developments with the potential for “significant” impacts on the physical environment to undergo an environmental review. 

Since its passage in 1970, CEQA (based on the National Environmental Policy Act) has served as a model for similar legislation in other states.

The California Aqueduct, a critical part of the State Water Project, carries water from the Sacramento-San Joaquin Delta to the San Joaquin Valley and Southern California.

Established as part of a $1.75 billion bond passed by voters in 1960, the 444-mile-long California Aqueduct (formally known as the Edmund G. Brown California Aqueduct) begins at the Harvey O. Banks Pumping Plant in the Delta. It parallels Interstate 5 south to the Tehachapi Mountains.

Aquifers are an unseen but critical resource in California’s water supply system.

These natural basins that sit below the surface are found underneath 40 percent of California’s land area.