The mismatch between water demand and water availability in many megacities poses vexing water management challenges. Managers are forced to take remedial efforts to address these challenges, often with a heavy focus on infrastructure solutions such as building reservoirs or interbasin transfers to meet demand, which may in fact exacerbate the problem through unintended consequences that arise from neglect of social, economic, and environmental factors. Such a situation awaits Beijing, China, which faces major water management challenges in spite of the addition of a large interbasin transfer to meet increasing demand. In this study, a sociohydrologic model is developed for investigating Beijing's future water sustainability from a holistic and dynamic perspective. Using the model, we first explore the sociohydrologic mechanisms that contributed to Beijing's worsening water situation during 1988–2014. We then use the model to assess possible future impacts of the South to North Water Diversion Project on Beijing's water supply prospects for the 2015–2035 period. Alternative futures are explored by combining three different sustainable management strategies. The model results show that the source of Beijing's dominant water pressure experienced a transformation from productive to domestic water use over the last 30 years. They also indicate that the transfer water via South to North Water Diversion Project cannot fundamentally reverse Beijing's water shortage in the long term and that demand‐oriented management measures will be required for alleviating the city's water stress. These findings provide guidance not only for Beijing's water management but also for other less developed cities around the world.

Abstract:The oceans are a crucial source of natural resources for human development, as productive terrestrial resources increasingly reach their limits of economic and ecological exploitation. With increasing human impact on oceans, it is vital to maintain a sustainable human-ocean relationship. We present an indicator system and information entropy model to assess the evolution of human-ocean systems (HOSs) according to the dissipative structure theory. Sustainable development ability (SDA) scores for HOSs are calculated based on the combination-weighting model. Finally, the Richards model is used to depict the HOSs' evolution states and periods in different coastal regions of China. The assessment indicates that total entropy is undergoing a process of negentropy; and that order degrees of HOSs are gradually improving. The results also suggest that the sustainable development levels of HOSs are continuously improving. The different coastal regions showed notable disparities of SDA and evolutionary processes, due to a differing resource base, environmental carrying capacity, and socio-economic development. Different limiting factors should determine regional policies for enhancing the SDA process; the key to sustainable development of HOS is achieving a balance between the exploitation of ocean resources for socio-economic development and conserving ecosystem services that are critical to wellbeing and livelihoods. OPEN ACCESSSustainability 2015, 7 10400

The impacts of climate change and human activities are challenging water sustainability in many cities around the world. Advanced understanding of the future long‐term coevolution of coupled urban human‐water systems is of considerable interest in this context. This study uses a previously developed sociohydrologic model to explore the coevolutionary trajectories of Beijing City's human‐water system over the 2015–2099 period under possible climate changes. The effects of multiple human adaptive actions under alternative climate scenarios are investigated in particular. Results show that there might be a recurrent competition for water between humans and the natural environment (e.g., groundwater aquifer) in the long‐term future, indicating that effective water management needs to ensure that this competition remains within a safe operating space. Three regimes of the human‐environment competition are revealed, including a sustainable development regime in which human society and groundwater aquifer are both safe throughout their coevolutionary trajectories, a regime that may lead to severe population loss due to overaggressive population control actions, and a regime that may cause aquifer depletion due to under‐perception of the drawdown of groundwater table. Results also show that relying too much on interbasin water diversion project might slacken human water conservation measures and eventually cause more severe aquifer depletion in the long run. Maintaining a high community sensitivity to drawdown of groundwater table and moderate measures to control population growth are keys to avoid unintended, negative consequences.