Protecting the multiple uses of a reservoir
Population growth and the increasing demand for water recreation—especially during the hot summer months—have put public and political pressure on water purveyors to make every body of water available for multipurpose use. At the same time, there is increasing evidence that full water/body-contact recreation such as swimming, wading, water-skiing, and Jet Skiing may add significantly more microorganisms such as viruses, Giardia, and Cryptosporidium to a reservoir compared with nonbody-contact recreation.
The South San Joaquin Irrigation District specifically sought to provide a safe reliable potable water supply, meet increased demand for recreational opportunities, continue to meet irrigation demand, and respect the needs of the farming community.
The district considered various alternatives to address the impacts of body-contact recreation and the California Department of Health Services (DHS) regulations prohibiting body-contact recreation at reservoirs used for a potable water supply. The addition of a second raw-water intake at Woodward Reservoir, located upstream and separated from the area of the reservoir used for body-contact recreation, was selected as the approach best able to satisfy DHS requirements and most likely to receive support from local agencies and the public.
The second intake will be used until reservoir levels drop to a level that requires use of the downstream main intake located at the dam. This will allow body-contact recreation to occur during the heavy use summer season when irrigation flows keep reservoir levels high. Body-contact recreation will be prohibited during the fall and winter months when the main intake is used.