Map Gallery Slide Show |
Image 41 of 75 |
CA Groundwater and Drought |
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CA Groundwater Basin Prioritization
- Groundwater Basins, Rock Type and Drought Conditions January 2014
thru December 2014 |
Ten years
of drought are taking a heavy toll on California's groundwater supplies.
Officials for the state's Department of Water Resources
reportedTuesday that hundreds of new wells dug this year have
contributed to drawing down water to historically low levels, causing
some land to sink. The report comes as Gov. Jerry Brown initiated new
laws to start managing the state's underground water.
Mark Cowin,
director of the water resources department, says that without careful
groundwater management, California risks losing a water source that
sustains cities and farms, especially during drought.
"If we fail
to manage our groundwater basins sustainably, we risk losing the water
supply savings account that can help cities, farms, and businesses
survive drought with minimal disruption," Cowin said in a statement.
"The Sustainable Groundwater Management Act will help us head off
problems such as subsidence and overdraft, which may damage aquifers
permanently, and allow local agencies to establish groundwater pumping
levels that yield reliable supplies for generations to come."
Groundwater basins are the state's largest reservoir collectively and
are 10 times the size of all surface reservoirs combined. In part, more
than 80 percent of Californian rely on groundwater for drinking water,
DWR said.
The report says Fresno and Tulare counties have seen
the most new wells dug with more than 350 each. Merced County saw more
than 200 new water supply wells; and Butte, Kern, Kings, Shasta and
Stanislaus counties saw more than 100 wells.
The report also said
34 of the 127 high- and medium- priority basins and sub basins are
partially or completely not monitored under the Statewide Groundwater
Elevation Monitoring Program.
In years of normal rain and
snowfall, groundwater accounts for 40 percent of supplies for farmers
and communities, and the report says that in times of drought, that
increases to 60 percent.
That increased pumping is causing
problems.
The San Joaquin River Basin is among those identified
as having notable decreases in groundwater levels. Maps included in the
report show the San Joaquin Valley covered with red dots, indicating
water levels have dropped by more than 10 feet since 2010.
In
some parts of Merced County, the report shows water levels plunged
nearly 50 feet during the past year.
Excessive groundwater
pumping, the report says, also is causing ground levels to drop, a
phenomenon called land subsidence. That, too, is apparent in Merced,
according to the maps.
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