"GROUNDWATER . You can't see it, but millions of Californians depend upon it as a vital source of water for their homes and businesses." Those are not my words but the introductory words for the promotional video that appears on the SGMA (Sustainable Groundwater Management Act) website1 . The statement is a rather simply worded way to convey the obvious: that groundwater is vital to our livelihood here in California, and especially important to honoring and sustaining our agricultural heritage. While groundwater provides needed sustenance for numerous rural, as well as urban communities, it is agriculture that demands the lion's share of the resource. Central Valley agriculture turns to groundwater pumping whenever drought or poor rainfall years reduce the availability of surface water deliveries. Cries for construction of more reservoirs to capture and store more stormwater and snowmelt so that canals can be filled with more water are always being heard. Yet, apart f