There is considerable discussion among commentators as to the identity of the Pool of Shelah
and the location of the king’s garden.
It is further debatable whether the wall
mentioned here is part of the city wall or a structure supporting this pool. The south and eastern walls of the city were built on (the edge of) a steep slope (Nehemiah 2:14), but there was water in this corner from the Gihon Spring.
15 And Shallum the son of Col-hozeh, ruler of the district of Mizpah, repaired the Fountain Gate. He rebuilt it and covered it and set its doors, its bolts, and its bars. And he built the wall of the Pool of Shelah of the king’s garden, as far as the stairs that go down from the city of David.