This year the state offers a new, scaled-down plan.Ĭross-Delta conveyance has to be seen in the context of overall water movements. 2 Efforts to alter this Rube Goldberg system have, one after another, died in controversy, due in essence to fears that improved engineering would lead to greater exports and lower outflows. The ill effects on salmon and other species-on an entire ecosystem-are well known, compounding the damage done by the sheer volume withdrawn. Accelerated currents erode banks and hurry nutrients out of useful reach. Plankton, eggs, and small fish vanish into the intakes many larger fish die in the works despite inadequate fish screens. These flows cut across natural seaward ones, causing water in many channels to run backwards at times. Water entering the Delta at the north exits at the southwest corner, drawn that way by three great arrays of pumps near Tracy, two serving the federal Central Valley Project and the third belonging to the State Water Project. A rare point of agreement is that the present arrangement is not satisfactory. The second question is by what route the water sent southward should travel. But almost one hundred years after it was first asked, this question is still in search of an answer. It is now seen much more in environmental terms. This issue nests inside a larger one: how much of the natural flow from the Central Valley watershed should still be allowed to follow its old route down various channels in the Sacramento-San Joaquin River Delta to Suisun Bay, San Pablo Bay, and San Francisco Bay? The debate used to be framed as an economic contest between the thirsts of a single Bay Area County, Contra Costa, and those of San Joaquin Valley and metropolitan southern California. Two great, intertwined, and unsolved questions haunt this north-south transfer. 1 The cross-Delta transfer still dwarfs any other single artificial movement of water in the state, and it is the link that binds the vast majority of the state’s water systems into an interconnected, though imperfectly integrated, whole. Feeling our way through a thicket of numbers, we can say that the Bay Area, the San Joaquin Valley, and metropolitan Southern California each get as much as a third of their supply via pumps at the Delta’s southern edge. Some regions do depend quite heavily on this water. Yet there are reasons why we can’t take our eyes off the Delta. Water moved in this manner makes up, on average, no more than a tenth of California’s developed water supply, and this proportion is decreasing. Sometimes it seems that California water debates revolve around a single question: how best to shift water from the Sacramento River, across, around or under the Sacramento-San Joaquin Delta, to farms and cities to the south and west.
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