And its canals will become foul: This line has a slight textual problem, not mentioned by Hebrew Old Testament Text Project. Masoretic Text is literally “I will reject/cast off the rivers.” Dead Sea Scrolls omits the first person pronominal prefix from the Hebrew verb. This results in a Hebrew verb form that occurs nowhere else but scholars believe it means “stink.” Most modern translations support this reading (so RSV/NRSV, Good News Translation, Contemporary English Version, New International Version, New Jerusalem Bible, New Jewish Publication Society’s Tanakh). Its canals refers to the branches of the Nile River that are like canals as they spread out from the main river. For canals we can say “channels” (Good News Translation), “streams” (New Jerusalem Bible), or “arms.”

And the branches of Egypt’s Nile will diminish and dry up: The branches of Egypt’s Nile is literally “the Niles of Egypt.” The Hebrew term for Nile is plural here. This plural form probably refers to the Nile River and its branches. The Hebrew word for “Egypt” is usually a dual form, but here it is singular. BDB suggests that the singular form is poetic. Since both of the first two lines of this verse refer to the branches of the Nile River, translators may combine them, as Good News Translation has done. Will diminish means the water level will drop. Then it will dry up. The order of events in the first two lines is probably as follows: first the water level of the Nile and its branches drops, then they dry up, finally they smell. Good News Translation reflects this and so does New Jewish Publication Society’s Tanakh with “Channels turn foul as they ebb, And Egypt’s canals run dry.”

Reeds and rushes will rot away: This is a another sign of the drying river. Reeds and rushes (or bulrushes) are plants that flourish along rivers. See 9.14, where a different Hebrew word for “reed” is used. Because of the drop in water level, the reeds and rushes that grow along the Nile will rot away, that is, die. This is a significant loss because of the role these plants played in the life of the river as well as the nation. Losing them would directly affect the Egyptians. They were used to make boats (see the comments on “papyrus” at 18.2), writing paper, clothes, rugs, sails, and ropes. They were also used as fuel, food, and medicine. Translators may combine reeds and rushes into one plant that is well known to grow along rivers. But they may also need to add a footnote to indicate the significance of these plants for Egypt.

For the translation of this verse we suggest the following examples:

• The Nile River and its streams will smell
as the water drops and dries up;
the reeds and bulrushes will die off.

• Egypt’s Nile River and its branches will stink
as they slowly go down and dry up;
the reeds and river grasses will die.

Quoted with permission from Ogden, Graham S. and Sterk, Jan. A Handbook on Isaiah. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here .