The focus of this book is on how we manage stormwater in our cities: water that falls from the sky and is not immediately absorbed by soil or plants, thus running over the surface to join a stream, and eventually flowing to the ocean. The increase in runoff that results from urbanization has traditionally been viewed as a liability, and public agencies have responded by designing flood control facilities with one primary objective: the protection of life and property. While this is the most important objective of flood management, it is time for traditional engineering approaches to broaden their scope to include the benefits that stormwater can provide in an urban setting. Stormwater can be used to replenish groundwater aquifers and to enhance recreational opportunities and wildlife habitat. This book begins with an overview of the hydrology of the Southwest and its range of weather patterns, the hydrologic changes that have taken place as our metropolitan regions have grown, and a review of traditional engineering solutions to stormwater runoff management. We then survey some of the alternatives to pipes and concrete which seem most appropriate to the rainfall and runoff patterns of the southwest. Finally, we present a sampling of some of the efforts underway to implement these so-called "best management practices" or "green infrastructure" strategies in urban areas such as Los Angeles and Las Vegas.