Water scarcity is a profound challenge for designers of the built environment. Beyond looking for water sources and creating sustainable ecosystems, how can we begin to create cities and buildings that will help us to celebrate and mitigate hydro-logical concerns? Hadley and Peter Arnold, co-directors of the Arid Land Institute (ALI) at Woodbury University, have decided to tackle this problem around Los Angeles. With the support of the World Water Forum and the Metropolitan Water District of Southern California, they recently developed a high-resolution geospatial model to strategically identify and quantify the potential for improving storm water capture within urban areas.