What is groundwater? Where does it occur in California? What is an aquifer? What is overdraft? And how can groundwater be managed? These are all important things to understand in a state where 40 percent of the water supply comes from underground.

But what does an aquifer look like? And how is water extracted for use on farms and in homes? Those questions are illustrated on the Foundation’s beautiful California Groundwater Map poster, which was updated and re-designed earlier this year.

Accompanying the map is the easy-to-understand 28-page Layperson’s Guide to Groundwater. This publication helps the reader understand how and where groundwater is used to irrigate crops and provide drinking water. Revised and expanded in 2017, the guide includes sections on groundwater law, the Sustainable Groundwater Management Act, groundwater overdraft, groundwater quality and groundwater management.

Both products retail for $15 each, but are now available in a bundle until Aug. 31 for just $20, plus tax and shipping.