We have a small spring in our yard beside a car sized boulder under several giant hemlock trees. There is a small cistern build to contain the spring water that the builder of the house used as their drinking water. A small creek empties from the cistern, travels through a culvert under the road and into the stream. There is the remains of an old low rock wall curving from the boulder to just past the cistern. I have a landscaping dream to some day clear out that area, extent the wall, and make small shaded cold water pond. Today, I was playing in that tiny channel of flowing water. I started my dropping a couple of large rocks and watching the flow respond the the obstacle. More rocks, smaller and larger were placed to maximize holding power and block flow. Eventually, I created a small dam, that backed the clear cold water into a small pool. The overflow gurgles down through and over the rocks I placed in the channel creating a soothing burbling stream noise. For now, this is good.