Urban transformation of river landscapes in a global context

摘要: Abstract Over the past 50 years considerable progress has been made in understanding impacts of urban development on river processes and forms. Such advances have occurred as population growth accelerated around world. Using a compilation research results from more than 100 studies conducted range areas (58 addressing morphological change), this paper describes how urbanization transformed landscapes across Earth’s surface, emphasizing distribution global comparative context. Urban induces an initial phase sediment mobilization, characterized by increased production (on order 2–10 times) deposition within channels, followed eventual decline that couples with erosion runoff to enlarge channels. Data humid temperate environments world indicate channels generally 2–3 times much 15 original size. Although emphasized environments, recent tropical tendency for channel reduction resulting strong responses because intense precipitation highly weathered soils. Embryonic arid further suggests variable are rapid change over short distances. Regardless location, persistence varies months several years, whereas decades likely needed enlarging stabilize potentially reach new equilibrium. Urbanizing streams pose particular challenges management given inherent changing nature. Successful requires clear temporal spatial variations adjustment processes.