Conjunctive use means actively managing the aquifer systems as an underground reservoir.
During wet years, when more surface water is available, surface water is stored underground by recharging the aquifers with surplus surface water. During dry years, the stored water is available in the aquifer system to supplement or replace diminished surface water supplies. Conjunctive use is an effective tool for increasing the overall water supply. DWR is studying several areas in the lower Sacramento Valley where conjunctive use operations may be possible. Conjunctive use requires both groundwater and surface water delivery systems.