SAN JOAQUIN VALLEY (CBS13) — A new study was released this week by the Jet Propulsion Laboratory of NASA.
The Department of Water Resources asked them to monitor the subsidence of land in northern California over the past two years. This is because it came to fruition a couple of years ago that the groundwater pumping in the San Joaquin Valley has led to subsidence or sinking of land in the area.
The land has been subsiding there for years, but it hadn’t been until just a couple years ago, while we were in the thick of the drought, that we started to see impacts to infrastructure in the area. Canals in the area are designed to move water downhill naturally using gravity. With the lowering of elevation of certain locations, water along these canals has slowed and need to be pumped. These pumps cost a lot of money and if the problem persists, we could see major impacts that could cost taxpayers more money.
The data released by NASA this week shows that the land in the San Joaquin Valley is still dropping. In some of the worst locations, by two feet per year. There are also new locations that are starting to subside. This includes Davis and Arbuckle in the Sacramento Valley. For the first time in the Sierra Valley, an area to the north of Lake Tahoe is also showing signs of subsidence.
There was some positive news when the report showed minor improvements in the San Joaquin Valley during the winter of 2015-2016 as the rain balanced out crop-water needs, but NASA says it will still take a long time to refill the substantial lack of water in the underground reservoirs.