Alternative Futures for a Floodplain in Nanchang City, China: Migrating Birds' Stepping Stone, Hydrolic Retrofit and New Urban Residences

Abstract

Landscape changes caused by rapid economic growth and broad scale rural-to-urban migration in China have contributed to significant degradation of natural ecosystems and loss of biodiversity in the past two decades. Nanchang City, the capital of Jiangxi Province in southeastern China, exemplifies the challenges of sustainable natural resource design and management implicit in a fast growing city. The city is situated in the floodplain of Poyang Lake, China’s largest freshwater lake and one that is characterized by a long history of frequent flooding. After the extreme floods in the Poyang Lake Region in 1998, the central Chinese government launched new policies to return reclaimed land to floodplains and the Poyang Lake, aiming to increase the lake size to its level in the 1950’s.The Poyang Lake Region attracts thousands of waterfowl each year including 95% of the world’s Siberian crane population. Due to loss of regional wetland habitat, migrating birds frequently visit green open space in the city. This phenomenon points to the importance of urban ecological design for Nanchang City. This study investigates the landscape history and the development trajectory of Taohua, a 3,022-acre green field in Nanchang requested for a future urban district. Situated between the Gan River and Xiang Lake, Taohua is one of the two large green fields in the Nanchang urban scope and is protected from floods by levees. The predominance of agriculture and nutrient rich aquaculture precludes the full realization of Taohua’s ecological functions and services despite its undeveloped status. Ecological restoration and improved flood protection have to be considered at the same time because it is essential to the public that the future is safe from flooding Therefore, this thesis utilizes a normative scenario approach to invent and evaluate three plausible and socially and ecologically desirable futures, with the final goal of educating the public and provoking a conversation among stakeholders about what the future landscape should be. Three radically different scenarios focus respectively on 1) enhancing stepping stone habitat for migrating birds; 2) reestablishing the hydrological network with improved flood management; 3) accommodating increasing land demand for new residents. All scenario designs draw inspiration from Taohua’s landscape history and are based on explicit ecological studies. Each scenario creates a future with explicit rendered landscape images to facilitate future decision-making. These scenarios demonstrate the way in which normative approaches can clarify and emphasize different ecological and social goals in a complex urban context.