San Joaquin Valley - Areas of Highest GW Overdraft

Using the same Department of Water Resources data for the period 1973-2009, we calculated the percentage of groundwater overdraft attributable to agricultural water use in each of the agency’s planning areas. This represents the potential reduction in groundwater use for agriculture if they position each region to come into balance for based on existing recharge and groundwater extraction data. Figure 11 highlights those areas where the potential reduction in water supplies to stop overdraft of groundwater basins is at least 25 percent of current agricultural use. This cutoff was used to highlight those areas that are expected to see the biggest impact from SGMA implementation affecting over 25 percent of their current water use and supply.