As discussed under Alma 17:26, Oliver Cowdery sometimes wrote waters in the singular (as water). Evidence throughout the text argues that there are only instances of “the waters of X” in the original text, never “the water of X”. Here in 𝓟 for Alma 43:40 (𝓞 is not extant for the word), Oliver initially wrote “water of Sidon” but then virtually immediately inserted the plural s inline; there is no change in the level of ink flow for this correction, just like in the examples of toward(s) discussed above.
Later in this passage, Oliver also initially wrote bank as the plural banks in 𝓟. In this instance, he erased the plural s (thus the correction was immediate). Either bank or banks is theoretically possible. The singular number is also consistent with other occurrences of riverbanks in the Book of Mormon. When referring to rivers rather than fortifications, there is only one occurrence in the text of the plural banks, and this is in 2 Nephi 18:7: “and he shall come up over all his channels and go over all his banks” (a quote from Isaiah 8:7 in the King James Bible). Otherwise, we have only the singular bank when referring to rivers:
It seems that here in Alma 43:40 the earlier plural, waters, may have prompted Oliver to accidentally write banks in 𝓟. A similar pluralization tendency, but in 𝓞, is found in the next verse:
Once more Oliver immediately caught his error and erased the plural s from sides to give the correct side (the immediately preceding other forces the singular side). For additional discussion of the tendency to replace side with sides, see under Alma 22:29.
Summary: Accept in Alma 43:40 Oliver Cowdery’s corrections in 𝓟 of water to waters and banks to bank; also accept in Alma 43:41 his correction in 𝓞 of sides to side.