Ditches - Or "pits" Jeremiah 14:3. They were to dig pits in the broad valley or wady, wherein the water might remain, instead of flowing off down the torrent course.

Make this valley full of ditches - The word נחל nachal may be translated brook, as it is by the Vulgate and Septuagint. There probably was a river here, but it was now dry; and the prophet desires that they would enlarge the channel, and cut out various canals from it, and reservoirs, where water might be collected for the refreshment of the army and of the cattle; and these were to be made so wide that the reflection of the sun's rays from this water might be the means of confounding and destroying the Moabites.

And he said, thus saith the Lord, make this valley full of ditches. In which the allied army lay encamped, that they might be ready to receive large quantities of water, sufficient for the whole army and cattle, when it came.

Make this valley full of ditches--capable of holding water.