Client has a small( 2 by 4' wide, 12- 6" deep), natural spring on a slight hill, directly under some pines. Want to enclose with rocks to create natural water feature. Wondered if anyone had done this before, or had thoughts on plants to use around it. Also, was thinking of using a minimal clay lining as well as small rocks; any thoughts on how intensive it needs to be lined, or what material to use? Any input appreciated.