Interpretation and application of Sponge City guidelines in China.

'Sponge City' is the term used to describe the Chinese government's approach to urban surface water management. The concept was conceived in 2014 in response to an increasing incidence of urban flooding or water-logging in Chinese cities. While ambitious and far-reaching in its aim (of decreasing national flood risk, increasing water supply and improving water quality), the initiative must be implemented by individual subprovincial or municipal-level government entities. Thus, while the concept is similar to sustainable drainage systems (SuDS) in the UK (or low-impact development (LID) in the USA), it is developing with different regional characteristics, and during continuing rapid urbanization. Indeed, the increasing use of national rather than international examples of best practice reflects a growing body of knowledge that has evolved since the start of the Sponge City initiative. In this paper, interpretation and development of the national Sponge City guidelines are assessed for the Ningbo Municipality, an affluent and rapidly expanding city on China's low-lying east coast. While climate, geology and socio-economic factors can all be seen to influence the way that national guidelines are implemented, project financing, integration and assessment are found to be of increasing influence. This article is part of the theme issue 'Urban flood resilience'.