What does Nehemiah 3:15 mean?

Shallun, son of Col-hozeh, who was in charge of the district of Mizpah, repaired the Fountain Gate. He rebuilt it, put up the roof, set the doors, and installed the bolts and bars. He also worked on the wall by the Pool of Shelah, near the king’s garden, all the way to the stairs going down from the City of David. Nehemiah 3:15 - Modern Text Bible

(This section included important water sources and royal gardens, so it was a high-profile job.)