There are two aquifers under here and one has an enormous amount of flow toward the sea. This is the one that is a series of basins which lies along the Great African Rift and is, I believe, under the shallower Libyan aquifer.
There are interesting tidbits about the ancients using mixtures of straw and clay to seal up openings all around Giza. I suspect this was to prevent the escape of CO2 which would sap the straighten of any geyser. The watertight pavements would have prevented the backflow of spend water which would dilute the waters of the abyss and prevent eruptions.
There is some of the most interesting geology in the world focused right at Giza but all Egyptologists want to talk about is the surface limestone.