I'm trying to do some planning about building a couple of ponds. One pond rule is that you never plant trees or shrubs on the dam - the roots can provide a way for leaks to form. Another rule is that if you plan to raise trout, you need to try to keep the water cool by shading it: plant lots of shady trees on the south side. What if the dam is on the south side? So I'm trying to think of some things .... maybe some shade trees that spread really wide planted on the east and west sides? But what would be a good variety? Weeping willow?