Tuesday, May 15, 2012

California Needs More Reliable Water Deliveries, Not More Delta Water


The Sacramento Bee editorialized over the weekend about the Bay Delta Conservation Plan (BDCP), articulating a position similar to many in keeping an open mind about a canal or tunnel that could eliminate the need to operate the major federal and state pumps in the south Delta that are harmful to California’s fisheries and the San Francisco estuary.
The Bee put its finger on a key issue in noting that, south of Delta exporters “seem to have an expectation that BDCP can provide them with even more Delta water – more than the record high pumping of the previous decade – and that federal and state agencies will sign off on such a plan as ‘fish friendly'."
The Bee quite reasonably points out that “living in the real world” means exporters “can't keep drawing ever more water out of an estuary in collapse and claiming that flows don't matter much for the life cycle of fish. The National Research Council, among other scientific bodies, has made clear that minimum flows are essential for fish recovery, especially during dry years.”
And The Sacramento Bee editorial concludes by recommending that:  “What these contractors should be seeking is what state law calls for – better reliability of water deliveries, not more total supply.”  EDF could not agree more.
Which raises the interesting question:  What is “better reliability” of water deliveries?  And how unreliable are things today?  We hear a lot about diminished reliability, but the numbers tell an interesting story:
The chart below shows State Water Project (SWP) exports south of the Delta starting in the early 1960s through last year.  The green dotted line represents hydrology, or roughly, how much it rained that year:
Two things stand out:
  1.  SWP deliveries have not been merely reliable, they have trended sharply up over time, especially during the 2000s.
  2. Trends aside, since the late 1980s, deliveries closely track hydrology – SWP contractors get more when it rains more.
By most measures, this record of deliveries, and increasing deliveries, has been quite reliable other than during very dry years.
Central Valley Project (CVP) Delta exports tell a similar story of relatively stable and high levels of deliveries, if not the very highest, for the last several decades:
None of which is to say that south of Delta exporters do not suffer serious consequences when there are cutbacks during drier years – of course they do.  The question for the State, as the Bee so crisply puts it, iswhether more reliable is the same as more.
Within the BDCP process, renewed efforts are underway to take a hard look at alternatives to Delta exports to shore up water supplies for those contractors who are among the first to be cutback during drought. The opportunities for better groundwater management, conservation, recycling, even graywater are substantial. And of course, in a state that consumes 40 million acre-feet of water on average each year, the potential for water transfers remains considerable.

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