History
Background
The Chino Groundwater Basin (Basin) extends beneath a portion of the Inland Empire, encompassing approximately 220 square miles. It is one of the largest groundwater basins in Southern California with roughly six million acre-feet of storage capacity, making it an integral component in meeting regional water needs. Groundwater had been pumped from the Basin for domestic and agricultural uses for many years, but in the 1970s, declining water levels and increasing levels of salt and nitrate induced interested parties in the basin to initiate an ambitious effort to manage this resource in a comprehensive fashion. In 1978 a California superior court established the Chino Basin Watermaster to oversee the Basin’s management. Initial steps included: identifying the Basin’s safe yield (the amount of water that can be pumped without causing groundwater depletion), establishing pumping rights, and providing for replenishment water in the event of overpumping.
These initial steps successfully stabilized the Basin, and in 1998, the full realization of the court order was implemented through the creation of the Optimum Basin Management Plan (OBMP), an extensive and detailed framework for the long-term management of the Basin’s resources. The critical goal of the OBMP is to maintain “hydraulic control” in the basin, which is to prevent groundwater resources in the Basin from discharging to the Santa Ana River and thereby 1) prevent loss of beneficial water for use in the basin, and 2) prevent degradation of water quality in the River due to salts and nitrates in the groundwater. In order to achieve this goal, the OBMP established a long-term goal of pumping 40,000 acre-feet per year from the lower portion of the Basin and treating the water with efficient desalting technologies to produce potable water supply for the region. The Desalters System concept was born, and the first desalting facility, the Chino I Desalter, was constructed and began operation in 2000. Construction was implemented by the Santa Ana Watershed Project Authority (SAWPA), which operated the facility until the Chino Basin Desalter Authority (CDA) was formed.
Formation of CDA
The Chino Basin Desalter Authority (CDA) was formed under a Joint Exercise of Powers Agreement (JPA) on September 25, 2001, by a group of seven local agencies, including the Cities of Chino, Chino Hills, Norco, and Ontario and Santa Ana River Water Company, Jurupa Community Services District, and Inland Empire Utilities Agency (IEUA). Western Municipal Water District was formally admitted to the CDA membership by the CDA Board on April 2, 2009, bringing the total number of member agencies to eight. The member agencies have a vested interest in the successful management of the Basin and the Desalter System to help meet the water supply and quality needs related to the region’s rapid growth. The CDA has been responsible for implementing and operating the Desalter System since initial construction of the Chino I Desalter with the goal of producing a safe and reliable source of potable water as economically as possible for delivery to the member agencies.
Desalters
The Desalters were established to preserve local groundwater resources for beneficial use by treating groundwater in the southern portion of the Chino Groundwater Basin, and helping the Chino Basin Watermaster achieve “hydraulic control” of the basin by capturing groundwater that would otherwise flow into the Santa Ana River. This is achieved through pumping 40,000 acre-feet-per-year (afy) from the Chino Groundwater Basin through a system of thirty wells, which convey flow to the desalters for treatment.
The Chino I Desalter is a drinking water treatment plant that commenced operation in 2001 to treat groundwater from twelve wells using reverse osmosis technology. Chino I was expanded in 2005 to add three wells, along with ion exchange and air stripping treatment technologies. In 2017, five additional new wells were added to further augment groundwater supply to Chino I. In 2023, granular activated carbon treatment was installed to treat organic compounds in the Basin. The Desalter currently treats groundwater from nineteen wells and produces up to 14 mgd of drinking water.
The Chino II Desalter became operational in 2006, treating groundwater from eight wells utilizing reverse osmosis and ion exchange technology at a capacity up to 13 mgd. In 2017, the Chino II Desalter was expanded by adding three wells, adding 10 mgd of additional reverse osmosis treatment capacity, and the addition of the Concentrate Reduction Facility. In 2021, addition of air stripping treatment was completed to treat volatile organic compounds in the Basin.