Albert Barnes Commentary Jeremiah 51:36

"Therefore thus saith Jehovah: Behold, I will plead thy cause, and take vengeance for thee; and I will dry up her sea, and make her fountain dry." — Jeremiah 51:36 (ASV)

Her sea – Probably the great lake dug by Nitocris to receive the waters of the Euphrates.

Her springs – Her reservoir; the whole system of canals dug (Jeremiah 51:13). The wealth of Babylonia depended upon irrigation.