Hope all is well.
Water is gravity feed. While it would flow towards the Faiyum Depression on one side, on the other side (the area of interest) it would flow in the opposite direction. It is this
area, I hope to generate a terrain height map. The Faiyum Depression, has never been considered, as it is much lower than the ground which surrounds the Pyramids.
Your 341ft. reading, is not accurate, according to Google Earth. The back section, at the base, of G1 is approx., 200 ft. A discrepancy of 141 feet. Khafre's chocolate quarry is slightly higher at 222 feet., enabling the AE to use a downhill ramp to the corner of G1.
I am using Google Earth live. Google Earth has been known, to be off by 15 feet. That was with an older satellite?
Please re-check your height.