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The Peripheral Canal is a recurring proposal to divert water from California's Sacramento River, around the periphery of the San Joaquin-Sacramento River Delta. It is currently proposed in the form of two tunnels to be constructed as part of the $25 billion Bay Delta Conservation Plan. Currently, freshwater entering the Delta has to flow from the Delta Cross Channel through a maze of river channels and sloughs before entering the Clifton Court Forebay north of Tracy, where water is pumped into the California Aqueduct and the Delta-Mendota Canal. Large numbers of Delta smelt and other endangered species are killed by the pumping plants, which provide water for the aqueducts. Freshwater flowing into the Delta displaces salt water entering from the San Francisco Bay. The freshwater to saltwater gradient has shifted inland because of increases in the amount of water being exported each year to the Central Valley and Southern California. The proposed peripheral canal would reduce the overall freshwater flow into the Delta and move the freshwater-saltwater interface further inland, causing damage to Delta agriculture and ecosystems. Senator Dianne Feinstein, former California Governor Arnold Schwarzenegger and current Governor Jerry Brown have all declared their support for the Peripheral Canal. However, the Peripheral Canal proposal has been criticized because it would further reduce the amount of freshwater flowing through the Delta. Farmers in the Delta are among the most opposed to the project because it would decrease the amount of water available to them for irrigation. On August 28, 2014 the United States Environmental Protection Agency commented that the plan could violate the Clean Water Act and harm endangered fish species. Before 2015, the Bay Delta Conservation Plan had two coequal goals of habitat restoration and water supply improvement. In April 2015, the habitat restoration plan and the water supply improvement plan were separated.〔(【引用サイトリンク】url=http://baydeltaconservationplan.com/2015News.aspx )〕 In effect, the 50-year guarantee to restore the Delta's environment has been dropped. ==Previous proposals== Prior to the 1940s, water was drawn from the southern end of the Delta. Since then, various groups have lobbied for the construction of a Peripheral Canal to instead draw water from the Sacramento and San Joaquin rivers to the federal aqueducts. Because of drought and other low flow issues that cause salty ocean water to flow from pumping stations which are located at the southern edge of the Sacramento–San Joaquin River Delta into the aqueducts of both the state (California Aqueduct) and federal government (Delta-Mendota Canal), aquatic environments as well as water for drinking and irrigation are contaminated. Thus, both state and federal agencies proposed a plan in 1965 for the second phase of the California State Water Project, which created a canal that would transport fresh water from the Sacramento River bypassing the delta, instead of through it.〔 Voters defeated a ballot initiative to build a similar Canal in 1982.〔(【引用サイトリンク】title=The California Peripheral Canal: who backed it, who fought it )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Peripheral Canal」の詳細全文を読む スポンサード リンク
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