 The USGS has performed several studies of the aquifer, to determine what is coming in (groundwater recharge from the surface), what is leaving (water pumped out and baseflow to streams), and what the net changes in storage are (rise, fall or no change).Withdrawals from the Ogallala Aquifer for irrigation amounted to in 2000.As of 2005, the total depletion since before development amounted to .