Bede

And a thousand cubits along the wall up to the Dung Gate, etc. They say that the site of the city of Jerusalem is arranged on such a gentle slope, facing north and east, that rain falling there never remains, but flows like rivers through the eastern gates, carrying with it all the filth of the streets, augmenting the torrent Cedron in the valley of Josaphat. From this, it seems likely that the gate is called the Dung Gate, through which filth and impurities are accustomed to be carried out. …

Commentary on Ezra and Nehemiah ↗