Streams and Urbanization

“Urbanization” encompasses a diverse array of watershed alterations that influence the physical, chemical, and biological characteristics of streams. In this chapter, we summarize lessons learned from the last half century of research on urban streams and provide a critique of various mitigation strategies, including recent approaches that explicitly address geomorphic processes. We focus first on the abiotic conditions (primarily hydrologic and geomorphic) and their changes in streams that accompany urbanization, recognizing that these changes may vary with geomorphic context and climatic region. We then discuss technical approaches and limitations to (1) mitigating water-quantity and water-quality degradation through site design, riparian protection, and structural stormwater-management strategies; and (2) restoring urban streams in those watersheds where the economic, social, and political contexts can support such activities.