this past fall I had a drive way and sidewalk installed in my already small back yard. this left me with 2 patches of yard about 20 by 10. both of my neighbors yards sit higher than mine, one is edged by a 1 ft high landscape timber wall. now with the melt, I have 2 small ponds in my back yard. how do I deal with the drainage dilemma. I can't dig down more than about 10 inches because of gas lines.