en_tn/isa/19/05.md

The waters of the sea will dry up, and the river will dry up and become empty

Egyptians referred to the Nile River as "the sea." These two phrases mean basically the same thing. AT: "The Nile River will completely dry up" (See: rc://en/ta/man/translate/figs-parallelism)

become foul

"become foul-smelling" or "stink"

dwindle

"be low"

the reeds and flags will wither away

"Reeds" and "flags" refer to two similar kinds of water plants. AT: "the plants along the river will die and decay"