Drought is nothing new for South San Joaquin Irrigation District.
There’s been seven droughts since the district that today serves 210,000 people in Manteca, Tracy and Lathrop along with 50,000 acres of irrigated farmland was founded 113 years ago.
In the seven years Peter Reitkerk has served as SSJID’s general manager, statistics kept by the Department of Water Resources based on measurements as far back as 1850 in California indicate there’s been two droughts — the one that spanned 2012-2016 and the current one that started three years ago.
That, however, is not the whole picture.
In reality California — and most of the West — has been in a prolonged dry period since 2005.
That’s’ s based on dendrology — the study of trees rings using carbon dating.
By using data collected from across a large swath of the West based on the fact the size tree ring growth occurs on an annual basis is determined by the moisture trees receive each year, researchers can construct hydrology models for various basins from the Colorado River to the Sierra runoff.
Based on tree ring data there have been five periods of extended dry hydrology in the West dating back to 800 AD that lasted between 50 and 100 years.
The worst was in the late 1500s. The third worst was in the mid-1100s. The fourth worst in the 800s, and the fifth worse in the 1200s.
The second worst?
We’re in it right it now. It started in early 2005.
The dry periods have all — just like the current one — been punctured with near normal years and higher than average years for precipitation.
The first drought of the current extended dry period was 2008-2009. The second 2012-2016 and the third that is now in progress.
That is why the growing concern in seven western states — including California — over diminishing water storage and precipitation on the Colorado River basin is a serious concern for SSJID.
Southern California’s vast cities and agriculture is fed by water from three out-of-basin sources — the Colorado River, the Sacramento River basin and the Owens River basins. All three areas are experiencing extreme drought conditions.
But the prolonged 20-year dry period coupled with development of the past two decades are creating serious supply concerns for basic health and safety needs in many areas throughout California including the south state.
Development in the western states essentially occurred from the 1850s to 2000 during an abnormally wet period. That means runoff projections to fill dams that have been built as well as the development the water system will support were based on periods of above average rain and snow.
“We are better situated (on the Stanislaus River basin) than many other areas in the state,” Reitkerk told the Manteca Rotary during a meeting Thursday at Mt. Mike’s Pizza.
If drought conditions persist for another year, there may be a serious need for the state to take measures to help the south state and other regions that will impact SSJID’s service territory and watershed that is also under extreme drought.
That’s because conditions are the same as they were in 2015. That’s when SSJID implemented mandatory cutbacks for 2016 on its farm and urban users that required a 20 percent reduction in use.
Reitkerk said the district and cities it serve will likely be OK for the rest of this year if they follow water conservation measures now being imposed by local jurisdictions. But if next year’s rain and snow isn’t significantly better than the current year, “it will be tight” in 2023.
Reitkerk indicated that’s why it is important water is conserved now so the region has a cushion going into next year.
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