The Not Empty Hole

Over much time he dug a large hole in the ground and filled it with water, and now that it was filled with water he called it a pond. What else would he call it? But the water all drained away, or evaporated, or something anyway, and once more it was just a hole in the ground. He saw what had to be done. There was a decent sized stream nearby forever rushing towards its great salty destination, and he began with pick and shovel to cut a channel at the correct gradient between stream and hole, which once more became not just a hole but a pond, and a pond it remained. It transpired in time he was even able to put any overflow to good use.