Some teach that the Yarden is from (part of) Eretz Yisrael, and some teach that the Yarden is from Chutz la'Aretz, and some teach that the Yarden is a border by itself (part is in Eretz Yisrael, and part is in Chutz la'Aretz).

The one who says that the Yarden is from Eretz Yisrael - "veha'Aravah veha'Yarden u'Gvul'';

The one who says that the Yarden is from Chutz la'Aretz - "Ki Atem Ovrim Es ha'Yarden Artzah Kena'an'';

The one who says that the Yarden is a border by itself "veha'Yarden Yagvil Oso li'F'as Kedmah.'' (If one has animals on both sides of the Yarden, it blocks them from joining - R. SHLOMO SIRILIYO.)

Limitation: This is only if it is in one place (but not if it split and there is land in the middle).

If the Yarden took\ from this [side, i.e. it became dry] and gave to this (water covered the land), what it took, it took, and what it gave, it gave;

Question: What is the case?

If it is in a place that was Eretz Yisrael and became Surya, [this cannot be, for] surely it retains its Chazakah for Ma'aseros and Shemitah!

Answer (R. Yirmeyah citing R. Imi citing R. Yochanan, and R. Simon citing R. Yehoshua ben Levi): It is for Chazakos (after three years, a buyer is believed to say that he lost his document if the owner was in the same region and did not protest), Bi'ur (in Shemitah, when the last attached Peros of a species are finished in a region, one must eradicate that species from his house) and (a division for) Ma'aser Behemah.

(R. Heila citing Reish Lakish): This is if it took earth (from one side and deposited it on the other side. It gets the law of where it is now for all matters - GILYONOS HA'GAON RAV Y. Y. KANIEVSKY. Perhaps SHITAH MEKUBETZES (Bava Metzi'a 22a) says that the Yerushalmi explains regarding Kedushah, for we conclude like Reish Lakish - PF.)