<P> The water - saturated thickness of the Ogallala Formation ranges from a few feet to more than 1,000 feet ( 300 m ) and is generally greater in the Northern Plains . The depth of the water below the surface of the land ranges from almost 400 feet ( 120 m ) in parts of the north to between 100 and 200 feet ( 30 and 61 m ) throughout much of the south . Present - day recharge of the aquifer with fresh water occurs at an exceedingly slow rate , suggesting that much of the water in its pore spaces is paleowater , dating back to the most recent ice age and probably earlier . </P>
how long did it take to accumulate all the water that is currently in the ogallala aquifer
dating back to the most recent ice age and probably earlier