Nice work, but ...


Matt Jenkins did a great job describing the intricacies of the California water wars in the Delta (HCN, 12/20/10).

But a few corrections: Jenkins said that two-thirds of the water used in the state is drafted from the Delta. Actually, only about 12 percent of the water used in California is taken from the Delta.

Jenkins wrote, "Most of the re-engineering was done to create the long-distance water extraction system." Not really. The only major work done in the Delta to accommodate water export was the Delta Cross Channel off the Sacramento River, and some channel work in the South Delta. The Delta was completely rebuilt in the late 19th and early 20th centuries, going from a maze of natural islands and channels to a highly engineered system. The vast majority of natural values were lost to irrigated agriculture.

Finally: "6.7 million gallons of water per minute" is about twice the actual pumping rate, and would produce deliveries of more than 10 million acre-feet per year. The actual rate is closer to 5 million acre-feet per year.

None of these errors take away from the central message of the story, which was extremely well done.

Jerry Meral
Deputy secretary of the California Natural Resources Agency in charge of the Bay Delta
Conservation Planning Program
Inverness, California

HCN responds
Mr. Meral's first point is an important one: On average, only about 12 percent of the water used in California is taken from the Delta. I appreciate his correction and regret my error. Nonetheless, most Californians are still directly connected to the problems in the Delta. According to the state Department of Water Resources, about two-thirds of the people in  the state receive at least some of their water from the Delta. I agree with Mr. Meral's point that the physical configuration of the Delta was most dramatically shaped by the farm-building campaign there. But I would point out that the installation of two giant batteries of  pumps that completely disrupt natural flow patterns is no small change. I stand by my assertion regarding the capacity of those pumps. When operating  at full throttle, they actually do pump about 6.7 million gallons of water per minute. As Mr. Meral correctly points out, they often operate at far lower levels -- but my intent in using this figure was to show that the pumps are quite powerful machines.

Matt Jenkins
HCN Contributing Editor

Delta Water Exports
John Shelton
John Shelton
Feb 04, 2011 01:39 PM
Part of the confusion concerning how much water is "taken from the Delta" is that there are some measures of how much water is actually exported once it gets to the Delta and how much is diverted before it ever reaches the Delta. Many statistics are an indication of water use of water that is "taken from" the Delta or its watershed, describing this as the total system. This concept of extraction from the total watershed (which includes the Delta) then would include a majority of California’s surface water development and only excludes some small rim reservoirs of the Tulare Lake Basin, the North Coast Rivers, a few (very) small central coast reservoirs and water from the Colorado. If you include ground water, the picture is more complicated given the inter-connections to surface water and the long term natural banking of water that is in many places being withdrawn and a rate higher then it is being replaced. For ecological purposes, there is a tremendous impact both from the Delta exports and the diversion of water before it makes it the Delta, and even impacts from the changes to groundwater levels that have occurred in the Delta's watershed due to groundwater overdraft.

As for the engineering that has changed the geography of the Delta, this is quite complex and also includes lots of work done to help pass flood flows and entrained sediment efficiently (for a better understanding look up issues with California's historic placer mining and its impacts. The important idea to keep in mind is that the very use of the large state and federal pumps has altered the hydrology, and the altered hydrology also changes land form. So in essence there are both direct and indirect affects from the engineering we have done.

I do think your original article was great and the clarifications were correct. Just wanted to explain some discrepancies....