Behind California's January Wildfires: Dry Conditions, Stubborn Weather PatternThe state is the driest it's been since the 1890s.
By Jane J. Lee
National Geographic
Published January 17, 2014
... Despite the voluntary restrictions on water use, California's residents shouldn't panic.
"The groundwater storage for southern California is still in pretty good shape," said Jackson [Mark Jackson, the meteorologist in charge for the National Weather Service's office near Los Angeles]. Officials build in a three-year buffer so that there is some protection against multiple dry years.
"But once we get past that third year, that's when we run into problems."
http://news.nationalgeographic.com/news/2014/01/140117-drought-wildfire-california-high-pressure-atmosphere-science/=======================================
From Wikipedia:... Groundwater is a critical element of the California water supply. During an average year, 40% of the state’s water supply comes from groundwater. In times of intense drought, groundwater consumption can rise to 60% or more.[3] Over 850,000,000 acre feet (1,050 km3) of water, enough to cover California to a depth of 8 feet (2 m) is stored in California’s 450 known groundwater reservoirs.[3] However, not all the water is usable. Over half of the groundwater is unavailable due to poor quality and the high cost of pumping the water from the ground. While surface water is concentrated mostly in the northern part of the state, groundwater is more evenly distributed.
The largest groundwater reservoirs are found in the Central Valley.[3] The majority of the supply there is in the form of runoff that seeps into the aquifer.
... Though California has laws governing surface water usage and quality, there exist no statewide groundwater management laws. Each groundwater basin is individually adjudicated to determine water rights.[4] Otherwise, for all practical purposes, land ownership implicitly carries the right to virtually unlimited groundwater pumping.
The large quantity of water beneath the surface has given rise to the misconception that groundwater is a sort of renewable resource that can be limitlessly tapped. While the volume of groundwater is very large, aquifers can be over drafted when groundwater is removed more rapidly than it is replenished.
http://en.wikipedia.org/wiki/Water_in_California