A panel discussion with audience Q&A following, featuring Spreck Rosencrans of Environmental Defense, Joel Pomerantz (author, "San Francisco's Clean Little Secret" in The Political Edge), and Ruth Gravanis, long-time San Francisco environmental advocate and activist. The existing water system is described, the history of the Hetch Hetchy system, the other sources of local water, a look at underground aquifers on east and west sides of the city, the historic creeks and lakes, and some of the remarkable facts about underground flows of fresh water. The role of stormwater management to wildlife habitat and urban greenery also is examined.