Subsidence

In the Central Valley, subsidence refers to the sinking or settling of the ground surface as a result of excessive pumping of groundwater. When groundwater is pumped out of the ground faster than it can be replenished, the water table can drop, causing the ground surface to settle or sink. This can lead to a loss of soil structure, cracking of the ground, and damage to buildings and other structures. In some areas, subsidence can be severe and result in significant economic losses for farmers and landowners. Subsidence is a common problem in the South Central Valley outside of The Oasis because of historical heavy reliance on groundwater for agriculture, urban water supply, and industrial use, and has been exacerbated by over-pumping and long-term drought. To mitigate the impact of subsidence, SGMA was passed to manage groundwater resources sustainably, by reducing pumping and increasing recharge, as well as by using alternative water sources and improving water conservation practices.