Why does it say "Maravah l'Gichon"?
Radak #1: This is like Ma'arav. A Hei is appended to the name superfluously, like "mi'Mizrach Shemesh umi'Ma'aravah" (Yeshayah 45:6).
Radak #2: The west of the wall was towards Gichon. The suffix Hei (here, and in "mi'Mizrach Shemesh umi'Ma'aravah" - Yeshayah 45:6) is a female pronoun (its west. Therefore,) it should be Mapik (Dagesh, i.e. have dot in the) Hei; these are exceptions. The word 'Shemesh' can be masculine or feminine. (In that verse it is feminine.)
Malbim: It was west of Yerushalayim.
What is "l'Gichon b'Nachal"?
'Rashi': It was by Nachal Gichon; it is the name of a place.
Where is "Sha'ar ha'Dagim"?
Malbim: It is in the east. The Ofel was there, like it says in Nechemyah 3:26.
What is the meaning of "v'Savav la'Ofel"?
'Rashi': He surrounded the towers built like fortresses.
Radak: He surrounded a high place in the wall.
