Tim, you do some great work. I was reading your posts on the Crites pond with all of the springs. I have a contractor working on a pond right now for me in southwest Wisconsin. It sounds like it may have been a similar situation. There was a spring that was present right in the area of the dam. It is definitely coming from uphill. The contractor made the core trench and upon filling it back in with clay, the downstream flow stopped behind the core trench. Onwards we went with the dam and all was fine until we got some rains that prevented any work for a week. Now there is noticeable flow just below the dam starting maybe 10 feet below dam. The water level in pond is not appreciably dropping (less than 1/2 inch per day), but there is constant running water (albeit not much) on backside of dam. The dam is not done yet. What would you do at this point? Would you go back into core trench and deepen it? Thanks for any insight, it is appreciated!