The figure below illustrates the growing popularity of perennial crops (citrus, subtropical, deciduous, and vine crops; seen in yellow) within the Subbasin over the past 20 years.
The number of perennial acres more than doubled between 1997 and 2016. Of the 47,218 new acres, 72% were converted into new fields from non-agricultural land, representing an increase in overall water demand. The remaining 13,060 acres (28%) were converted from existing farmland. Because perennial crops incur high initial investment costs and are more permanent installations, their demand is less flexible in times of drought. These 13,060 acres represent a hardening of demand in the basin, decreasing the amount to which water demand will respond to water availability.