Hiya Ginger,
What part of the world are you from?
Your tree's botanical name is: Acer rubrum. The leaf loss is quite normal as your tree is deciduous. A deciduous tree will loose it's leaves once a year for the winter, then come spring time it will grow new leaves.
As for the moist area, although tree's do love water, their roots also have to breath. So if the area that it is planted in is drenched in water then there is not enough oxygen for the roots and infact it is drowning.
If you could post some pictures of your tree, that always helps when we can see what we're dealing with. |