How have they done that? Encapsulating the soil with a barrier layer?
Of course they do lots of hydroponics too, for the usual hydroponic crops (tomatoes, cucumbers, etc.). The science in hydroponics and science in sophisticated soil culture aren't really that different--you'll see mostly the same chemical fertilizers, the same EC and pH measurements in the field, the same lab analyses by ICP, etc.
Some water still drains to the aquifer and is "wasted". It needs to be though, or else unwanted ions (from impure source water or fertilizer, including but not limited to Na+ and Cl-) would accumulate and kill the plant. Israel has a significant problem with salinization of their soils and groundwater, and lots of interesting work modeling that.