What is the grammatical form of "v'He'eznichu"?
Radak #1: The Hei is part of Hif'il conjugation, like Hifkidu; the Aleph is extra.
Radak #2: The Aleph is Arame'ic, like "Ishtiv Chamra" (Daniel 5:4); the Hei is Hebrew.
Radak citing his brother R. Moshe: The Aleph is in place of Hei of the root, like "Malbushai Eg'alti" (63:3), and the Hei is like "he'Hashev Ashiv" (Bereishis 24:5), in place of Im (if) - will they be distanced? I.e. the Naharos will dry - will the Ye'orim dry? The Ye'orim are [filled] from the Naharos. He'eznichu is distanced, like "va'Tiznach mi'Shalom Nafshi" (Eichah 3:17).
Why are the rivers abandoned?
Rashi: When the water diminishes, they become muddy.
What is the meaning of "Dalelu"?
Rashi citing Macheberes (of Menachem): This is [poor,] like "v'Im Dal Hu" (Vayikra 14:21).
Radak: They became desolate, like "Dalu me'Enosh Na'u" (Iyov 28:4).
Malbim: They became totally dry.
What are "Ye'orei Matzor"?
Rashi: They are deep irrigation channels, like ditches of those who besiege cities.
Radak: They are the minor rivers of Egypt.
Malbim: They are manmade channels to bring water to deep pits to last for a long time at a time of siege, when one cannot draw from the Nahar.
What are "Kaneh va'Suf"?
Rashi: They are reeds that grew there due to the abundance of water.
What is the meaning of "Kamelu"?
Rashi #1: When the Ye'orim dried, the reeds ceased to grow, and they dry and fall. Yonason translates, they will not go up. Below (33:9), he translated "Kamal" to be Nesar (falling or withering).
Rashi #2: It is an expression of cutting. They are cut by themselves due to dryness, and they fall. Malbim - they dried because there was no moisture at all (in the Ye'orim).
