http://danvillesanramon.com/blogs/p/print/2013/12/26/time-for-a-rain-dance


Local Blogs

By Tim Hunt

Time for a rain dance

Uploaded: Dec 26, 2013

The continued freezing nights and warm afternoons are great for outdoor activities, but forget snuggling by the fireplace in this month of Spare the Air days.

The high pressure system that seems to have dominated Bay Area weather throughout winter months of 2013 has the area on track to endure the driest calendar year on record. If you recall, the fall of 2012 was marked by near record rainfall that almost stopped completely once this year dawned. It has not gotten any better.

For farmers, they are planning what not to grow in the great San Joaquin Valley because they are facing a preliminary allocation of just 5 percent of their requested water supplies. That could change if the rains and snow arrive, but the situation and the relatively low levels of the reservoirs likely will mean fallowed land and relying more heavily on ground water pumping.

Reports earlier this month detailed the amount of subsidence in areas on the western side of the San Joaquin Valley as over drafted aquifers subside and the ground sinks. In other areas (eastern Merced County and the Paso Robles area) the county Board of Supervisors have exerted emergency control over pumping ground water because shallower wells serving rural residences have been going dry. Watering acreage of permanent crops that have been expanding (grapes in Paso Robles and nut and fruit trees in Merced Country) have been linked to the dropping ground water table.

Here in the Livermore Valley, earlier resident faced the same challenges—over-drafted ground water supplies. They had the foresight, more than 50 years ago, to form the Zone 7 Water Agency and charge it with managing the ground water table. Those visionary leaders also tapped in the State Water Project because they realized that importing water was going to be necessary for the valley to grow.

Today, as areas around the state wrestle with water challenges, Zone 7 is relatively secure with an ample reserve in the ground water basin available for supplies during a drought. In normal years about 80 percent of the water delivered to the cities of Livermore, Pleasanton and Dublin as well as the Dougherty Valley area in San Ramon, is conveyed across the Delta to the State Water Project pumps near Tracy and then moved into the valley in the South Bay Aqueduct (visible south of Interstate 580 a bit beyond the Greenville Road bridge and then along Greenville. Water also is pumped into Lake Del Valle, complementing the runoff in the water shed.

Given how dry 2013 turned out to be, 2014 likely will be a year with more ground water pumping to offset lower deliveries from the Delta. The valley is fortunate to have that reserve and we all should be grateful to community leaders who took wise moves to develop a sustainable water supply back in the 1950s.
NOTE: I have followed water and water politics since the 1980s and have consulted with Zone 7 on Delta and other public affairs issues.

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