The Pomona Valley Protective Association (PVPA) is a non-profit corporation governed by a nine member Board of Directors. The Corporation currently has seven major shareholders: City of Pomona, Southern California Water Company, West End Consolidated, American States Water Company, City of Upland, San Antonio Water Company, and Pomona College.

The San Antonio and Thompson Creek Spreading Grounds

The San Antonio Spreading Grounds consist of an area of approximately 970 acres (approximately 720 acres of which are owned in fee by PVPA). The Thompson Creek Spreading Grounds consist of an area of approximately 140 acres owned in fee by PVPA, approximately 70 acres of which are currently used for spreading.

The U.S.Army Corps of Engineers completed the San Antonio Dam in 1956. An area of approximately 26 square miles behind the dam constitutes the San Antonio Reservoir. (Photo: San Antonio Reservoir) The concrete San Antonio Channel, into which storm waters are released, was completed in 1960. The San Antonio Dam is an earth filled dam, 160 feet above stream height, with a drainage area of 26.7 square miles. (Photo: San Antonio Channel)

PVPA works directly with the Corps of Engineers for water conservation releases. The water is released into a concrete lined channel where the flow is then directed onto the Spreading Grounds.

The San Antonio Spreading Grounds are divided into two sections, the Los Angeles side and the San Bernardino side. The San Antonio Channel is considered the dividing line between the two sides. Water is released onto the grounds through six sluice gates located within the San Antonio Channel, where the flow is electronically metered and recorded.

Thompson Creek Dam and Spreading Grounds

The Los Angeles County Flood Control District constructed the Thompson Creek Dam in 1931 on PVPA land. The land on which the Dam was constructed was deeded to Los Angeles County by PVPA. PVPA and Los Angeles County Flood Control work together to operate the Thompson Creek Spreading Grounds, and to conserve and spread the waters flows onto the property. (Photo: Thompson Creek Dam

Various judgments such as Pomona Land and Water Co. vs. San Antonio Water Co., Irrigation Co. of Pomona vs. San Antonio Water Co., and Del Monte Irrigation vs. Mountain View Water Co. have adjudicated the surface water rights in the San Antonio Canyon. Under these judgments PVPA has the responsibility for spreading and conserving certain waters originating in the San Antonio Canyon and tributary canyons.

Both the San Antonio and the Thompson Creek Spreading Grounds are surrounded by homes. PVPA prides itself on being a good neighbor who is willing to work with and respect its neighbor’s property. To this end PVPA maintains a weed abatement and trash removal program on its property.