144 Urban Design Ecologies 145 Mega Urban Ecologies Mega Urban Ecologies Sharon Haar and Victoria Marshall Through most post-Second World War history there were two very different trends in global urbanisation – the exodus of residences, business and commercial areas to a wide car-based megalopolis of the developed world and the implosion of megacities through massive rural to urban migration in the developing world. Sharon Haar and Victoria Marshall combine their research experiences in the Pearl and Yangtze River deltas in China to describe a new hybrid megaregional development containing both megalopolitan car-based sprawl and megacity implosion. Haar and Marshall examine how slight shifts in the superposition of the new megablock structure of Chinese urbanisation can better accommodate the historical hydrological network of the historical delta cities of China. Introduction China’s explosion of urbanisation offers a redeinition of both the megacity and the megalopolis. Situated within a culture and state structure that privileges ‘planning’ – of cities, the economy and social relations – China’s cities do not it neatly into the category ‘megacity’ represented by cities of the Global South. While sharing many causal factors and statistical narratives with cities such as São Paulo and Mumbai, known for their intensive rural in-migration, in China the planning and design of both existing and, increasingly, new cities operates within different registers. Similarly, as China quickly builds a 21st-century infrastructure to support megalopolitan regions already irmly in place, Chinese cities do not cleanly follow the American patterns of suburban and exurban sprawl. Rather, Chinese urbanisation is a process that reorganises and radically transforms existing ecosystems into oficial ideals of nature and city. Two case studies, one an analysis of the New Administrative District in Shunde in the Pearl River Delta and the other an urban design proposal for Shaoxing in the Yangtze River Delta, will illustrate how large- scale, planned development in China is used to intervene in and control the informal production of the megacity, built atop and expanding upon the pre-modern aqua-urban network of two megadeltas. 1 Within these vast deltas we observe and analyse Chinese planners’ attempts to integrate the dispersed urban elements of the new megalopolis created by duplication, replication and excess through an endless repetitive grid that threatens the intricate urban water-land interactions of two megadeltas. Much of the contemporary understanding of Chinese urbanisation derives from the study of the spectacular explosive growth of cities such as Shenzhen in the Pearl River Delta and Shanghai in the Yangtze River Delta. Here we focus our attention on two lesser- known cities in these regions to illustrate more generic urban processes that are taking place throughout China. Structuring our discussion within a patch dynamic framework rather than a centre/periphery dialectic, we irst analyse existing Chinese planning and design The Pearl River Delta showing the shift of mud and construction of levees, villages and cities from the 1950s to the present. This is a small snapshot in time of millennia of water- land transformations in this delta.