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Whiskey, Tango, Foxtrot | The land subsidence in the SJV is nothing new. The cause, as stated in the article, is mostly groundwater pumping. But as noted in the article, it started back in the 20's and 30's when pumps and electrical power became widely available. So a lot of land was developed. The SJV is incredibly productive. It's a concentrated area of over a million acres, with all the right things. Soil, climate, markets, infrastructure, all you need to do is add water, because it's too dry to grow crops without irrigation.
So initial developments were with surface water from the rivers coming out of the mountains. Kings, Kern, Tuolumne, Stanislaus, San Joaquin Rivers all flow out of Sierra Nevada mountains, and were easily developed with storage reservoirs and gravity canals to serve the east side of the valley. Much of it by individual irrigation districts. The west side doesn't have much for surface water, so they developed groundwater. Not all of it had groundwater, and by the 40's it was apparent that the pumping was causing subsidence, so the Feds got involved with the Central Valley Project. Later on in the 60's, the State got involved with the State Water Project. The end result of both of these is large storage reservoirs (Shasta and Oroville) in the north part of the state, and then massive pumps in the Sacramento/San Joaquin Delta basically at sea level. These pumps take water out of the delta before it flows out through San Francisco Bay, and pump it south along the west side of the San Joaquin Valley in the Delta Mendota Canal and the California Aqueduct. Believe me, they are impressive sized rivers, essentially, running up hill through the valley.
All that engineering actually did fix the problem. By adding some off stream storage at San Luis, some groundwater banking, tie in connections with other facilities, it worked. Unfortunately, anything that works generally draws the attention of someone who's irritated by success. In this case the environmental movement took it upon themselves to claim some fish were being adversely affected. Probably, but there's 30 million people and most of the food in the country being grown in the state, so it's going to have some affects to the environment. What's happened is ever increasing "environmental" or fishery flows, to the point where very little water is being diverted to serve agriculture. Ever increasing amounts of water are simply being wasted to the sea, in the name of saving a fish (the delta smelt in this case, salmon also) that is probably extinct anyway. \
We all know as farmers you can't just stop farming. Many of these crops are contracted, many farmers also owner packing sheds or are otherwise vertically integrated. So people went back to pumping groundwater to get through a dry year, and as things have gotten worse the reliance on groundwater has continued. Drought is part of it, it makes the issue worse, but the underlying cause is reallocation of water to instream uses. This is only getting worse. There's plenty of water in CA to keep farms going, even in a dry year. The problem is that water has been taken to serve other uses. If the reservoirs and canals were managed they way they were intended, or heaven forbid we even built a few new reservoirs, we wouldn't have to pump groundwater. They wouldn't have problems with subsidence. It's not a drought, water, or engineering problem. It's a problem of what we decide as a society is a beneficial use of that water.
I can chime in more later with some good links. | |
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California land subsidence.. ground water pumping
