As a village grows into a city, its surfaces increasingly become covered by materials that prevent rain from soaking into the ground. Even small rainfalls on these impervious surfaces produce high stormwater flows of short duration, which pick up sediments, heat, and pollutants, and requires the construction of pipes to carry the flow that further concentrates the stormwater. High volumes of polluted water discharged into streams causes loss and damage to downstream ecosystems and the water resources that people need. This book presents and explains the diverse scientific aspects of urban stormwater by summarizing the primary academic literature with more than 250 plots, figures, and tables, and a bibliography of more than 450 references. Ideally suited for individual study or an advanced undergraduate or graduate seminar, each chapter provides several suggested references for deeper analysis. The 13 chapters are grouped into three parts covering urban conditions, environmental harms, and solutions. Urban conditions covers the water cycle and climate change, pollution emissions and deposition, and the various facets of imperviousness. Individual chapters on environmental harms cover distinct pollutant categories such as nutrients, mercury, and heat, as well as chapters detailing stormwater influences on streams, groundwater, and ecosystem responses. Solutions are grouped into two chapters, one covering the services provided by natural ecosystems and another chapter discussing the benefits of design features ranging from rain barrels to porous pavement to careful construction practices.