Two thoughts, first, when you add height, you need to add width. Since water weighs 8.14 pounds per gallon, adding two or three feet significantly increases the pressure on your dam.
Secondly, adding a lot of two to three foot deep water will significantly increase the water weeds. Weeds grow in water that is shallow enough for the sunlight to reach the bottom. Pond edges are recommended to be steep in order to minimize weed growth.
Oh yea, lastly, it is dam when you say it nice. Add an "n" at the end and your cussin.
