On August 7, the thesis Manage water in a green way written by Professor Liu Junguo in our School as a corresponding author was published by Science, the international top-level comprehensive academic journal.

Figure of thesis

Construction of water conservancy project, also known as "grey" infrastructure, is a traditional method for water resources management and supporting development of social economy. But infrastructures such as dams, water delivery pipes and protective barriers are often costly. And grey infrastructure would destroy biophysical process which ecosystem and residents' livelihoods depend on. So people began to concern themselves with “green” infrastructures which are more flexible with cost-effective price and various ecological service functions. But currently researches relevant to comparison between green and grey infrastructures are still rare.

Green infrastructures refer to space network composed of natural or semi-natural areas with similar functions and design goal of grey infrastructures. Ecosystems such as wetland, good soil, forests and snow covers able to produce runoff are of functions such as to provide pure drinking water, adjust flood, control water and soil loss, store water for hydroelectric generation and irrigation. These ecosystems can also be used to manage water resources as an alternative method of water conservancy project. For thousands of years, human civilization has long depended on the natural process in combination with proper methods and techniques, supplemented by few external investments with using and allocating water resources.

At present, there are few reports about the cost effectiveness of green infrastructure, and even more few reports about the cost effectiveness comparison of green infrastructure. Economic and efficiency analysis is the common method to estimate gray infrastructure, but the methods like this often under-estimate the cost of hydraulic engineering. For example, it is estimated that three-quarter dam projects in the world will overspend, and be 96% higher than the average estimated cost. Although green infrastructure is more sustainable and economic than the traditional method, the cost and effectiveness research about green infrastructure is seldom. Therefore, it is very important to evaluate the economic effectiveness of green infrastructures such as wetland, tidal flat, coral reef, etc.

On the basis of reviewing a large number of literatures, this article summarizes the key scientific issues about the water resources management of green infrastructure, including how to evaluate the implementation effect of green infrastructure, how to build “social hydrology” model to evaluate the effectiveness and social acceptability of infrastructure, and how to evaluate the hydrological circulation influence of ecological recovery project, etc.

The article also shows that if the gray water infrastructure has high reliability and low failure rate, these infrastructures may be the most effective method to carry out water resources management. However, gray infrastructure will damage the ecological system and affect residents’ livelihood. Therefore, green infrastructure may be a more safe and conservative way. But the “multi-functionality” of green infrastructure has not been known widely yet, and the shortage of costs and benefits data increases the risk that it is widely applied. Under the backgrounds of the rapid development of social economy, the increased uncertainty of global climate change, and the heavily damaged ecological environment, it has the vital practical significance to deeply discuss and quantize the long-term sustainability of infrastructures, and conduct trade-off analysis for their environmental and economic influences.

Water resources problems have become the key bottleneck problem which restricts global social economic sustainable development. On the basis of reviewing the effect of green and gray infrastructures on water resources management and their cost effectiveness, the article summarizes the key scientific issues of research on green infrastructure. At the same time, it highlights that it is very important for meeting current and future water resources demands to supplement or integrate the green infrastructure based on ecological system on the basis of gray infrastructure. This article points out a “green” road for solving increasingly outstanding water resources problems, and provides theoretical basis for guaranteeing global and regional water security and ecological security.

Professor Liu Junguo is the key talent introduced by the Environmental Science and Engineering College in our university and he has rich working experiences in China, America, Britain, Switzerland, Austria, Netherlands etc. He was the inductee of the first batch “Outstanding Young Scholars” of the the Organization Department of the Central Committee of the CPC and mainly engaged in the study on the ecological aspects of hydrology and water resource and wetland. He published over 70 papers on Nature, Science, PANS and other publications. The published articles were cited for over 1200 times by Nature, Science and other journal articles. Some articles were awarded as “the most influential international academic paper” among China Hundred Pages and “ESI highly-cited papers in the near 10 years around the global”. Professor Liu Junguo serves as the co-editor of International Water Association SCI Journal and Journal of Water and Climate Change, director of Beijing Ecological Rehabilitation Association, as well as the expert of peer review of Science and PNAS. He also holds concurrent posts of member of the United Nation Best Practice Award Technical Advisory Committee and International Water Footprint Network Peer Review Expert Committee, primary member of Netherlands “Environment and Sustainable Science” professional assessment jury and member of International Ecological Rehabilitation Conference Academic Committee and so on. He plays a leading role in the development of international hydrological science with his academic achievements in the aspects of blue-green water, water footprint, virtual water, ecological hydrology and so on. In 2015, he became the leader of ten-year scientific program of International Association of Hydrological Sciences (IAHS), one of the seven leaders throughout the world, and is responsible for the promotion of ten-year scientific program in the world.

Paper Site: http://www.sciencemag.org/content/349/6248/584.2.summary