Administrative-Hierarchical Urban Land Expansion in China: Urban Agglomeration in the Yangtze River Delta

Urbanization in China has been strongly controlled by the administrative hierarchy system. Using Landsat images, this study compares the rates and forms of urban expansion across cities in the Yangtze River delta urban agglomeration in China between 2000 and 2015. Results indicate exponential downward trends of urban areas, urbanization levels (percentage of landscape taken by urban land), and urban growth with lower city administrative powers. Annual growth rates of urban lands peaked in relatively lower-level cities (county-level) and were lowest in top-level cities (directly controlled municipality/provincial capital). Also, this study shows that forms of urban growth were dominated by edge expansion (followed by leapfrogging) regardless of administrative position, and growth in lower-level cities tended to be more diffuse, fragmentary, and irregular. These findings highlight the administrative-hierarchical urbanization processes in China, along with the government's increasing emphasis on the development of medium- and small- sized cities within urban agglomerations. More in-depth study is needed to find a balance between urbanization and environmental sustainability for urban agglomerations. (C) 2018 American Society of Civil Engineers.