White membrane roofs don’t have the same benefit as green roofs because they don’t reduce storm water runoff from impervious (and dirty) city surfaces (like roofs and streets and parking lots), and runoff of this kind is one of the biggest contributors to polluted water in our streams and rivers, and therefore, our drinking water. Storm water runoff also artificially increases the amount of water that flows into streams (because the rainfall is not absorbed by plants and soil), which leads to stream bank erosion and destruction of fish habitat. Lots of fishermen and women would like to see improved fish habitat.