Genesis 26:17: Asked to leave a town, and moving as far as the wadi below it

"So Isaac departed from there and encamped in the Valley of Gerar and settled there." He has been asked to go. Isaac sowed in a famine year and reaped a hundredfold, the flocks multiplied, the Philistines envied him, and Abimelech said the quietest eviction in scripture: go away from us, for you are much mightier than we. So he goes — about as far as a man can go while still being in the same place. The Valley of Gerar is the wadi the town stands over. Today it is the Nahal Gerar, a dry bed for most of the year that runs west from the hills above Beersheba, past the mound at Tel Haror, and on to join the Besor before the sea. Moving from the town into the valley is a move of a mile or two and a change of status: out of the settlement and into the open ground below it, where the water is under the sand and the wells are. The sources cannot fix the valley on its own. Every identification of it resolves to whichever mound that source proposes for Gerar itself — four of them, spread over about fifteen miles of the same wadi — which is a way of saying that the valley is known only by the town, and the town is what is being argued about. So it carries a ring rather than a pin, at the leading mound, and the wadi is drawn as ground because the wadi is what the verse is about. Everything that follows happens along this line. Three wells in the next five verses, two of them fought over and one of them not, and then the ground runs out and he goes up to Beersheba. The map of Genesis 26 is really the map of this watercourse.