What you are looking for is compaction of the soil to see if you have a good site to build a pond?If I were you I would contact water and soil conservation and they will come out to site where you would like to build your pond and tell you the probability of your desires. The service is free. I had it done for my pond. I had a backehoe dig some testholes about 6 and they said that the soil was great. You want clay. Hope that this will help you with your situation.