Ecological water, a new focus of China's water management

Water set aside for environmental purposes is now the fastest-growing category of water use in China. Since 2000 this 'ecological water' (EcoW) has grown to make up 5 % of the total water allocation (around 30 billion m³ of water). This paper provides the first substantial review of the history, definition, and policy rationale for EcoW in China, and allows us to compare the Chinese program with elsewhere. As in most countries, the growth in EcoW is a response to the over-allocation of water, and a recognition of the broader values of aquatic systems. In contrast to other countries, most EcoW is still allocated to support human values more than natural values. The earliest, and most celebrated EcoW projects, were directed at reducing dust pollution from arid zone rivers affecting northern China. In other countries, most environmental water is clawed back from other users in a catchment (usually irrigators) and is then delivered as a quasi-natural flow regime from a dam. These sorts of environmental flows from dams do occur in China, represented by the EcoW diversion in the Heihe River Basin and the Yellow River Basin. By contrast, the largest EcoW programs do not replace existing uses. Instead, they augment flows through large interbasin transfers. The largest and fastest-growing EcoW program in China is on the North China Plain (NCP) based on excess water available from the South-North Water Transfer project. To illustrate the complexity of EcoW projects in China, we describe in more detail two case studies, the well-established arid-zone Heihe EcoW program and the newer Jin-Jin-Ji EcoW program on the NCP. Overall, ecological water allocation in China reflects a major development in water management in that country and a growing shift toward more holistic water management.