I had two holes dug, each 3' deep and partially filled them with manure/soil/compost. However, the pH was way low and I had to remove all the "stuff" in both holes hoping to adjust the pH. My pH meter was faulty. After the winter the holes were filled with rain/snow water up to ~ 9" from surface. I pumped the water out of both holes with a small electric pump, and then went to Home Depot to get something to cover the holes before it rained again. To my surprise the holes had partially filled with water again but it hadn't rained! finally figured out that it was ground water as the water table here in the spring is VERY high. In disgust I just refilled both holes with "stuff".