“A Sacramento Superior Court judge issued a ruling Tuesday requiring regulation of groundwater pumping to protect a river in Siskiyou County. Attorneys on both sides say it’s the first time a California court has ruled the “public trust doctrine” applies to groundwater. The doctrine says the State of California holds all waterways for the benefit of the people.” Source: Capital Public Radio
The significance of this is that up until now counties were allowed, or permitted, to regulate groundwater. Under this ruling, it would be required (by application of public trust principle). The ruling will likely be appealed, but due to the drought, having greater control over groundwater usage will be extremely important since it has a direct relationship to surface water flow.