A multi-objective optimization approach for sustainable water management for places with over-exploited water resources

Cultural Values in Water Management and Governance: Where Do We Stand?

Research in water governance and management is a complex subject that involves the appraisal of social, economic, and environmental–biophysical aspects. Cultural and social values are regarded as key drivers in decision-making processes in both domains. Identifying relevant cultural values however is difficult given the interdisciplinary nature of theoretical frameworks and the implementation and operational needs of water governance/management research. In this work, we conduct a systematic literature review and thematic analysis of existing theories of culture (ToC) to identify common cultural values, theoretical frameworks, disciplinary trajectories and implementation trends relevant to water management and governance. Results indicate that the dominant ToC corresponds to Cultural Theory with its four defined categories (Egalitarian–Hierarchist–Individualist–Fatalist). In addition, results show emergent cultural values linked to “local” place-based knowledge perspectives indicating a more pluriversal understanding of cultural values. Cultural values associated with water management revolve around anthropocentrism, whereas values associated with water governance revolve around concepts of provenance/places. Implementation of ToC/cultural values is limited in practical applications, and we provide an example on how to improve on that. We suggest a succinct theory of culture such as Schwartz’s cultural values be considered to be an alternative to capture a greater heterogeneity across the breadth of water governance/management-related and basin-specific contexts.

Optimal Design and Operation of Multi-Period Water Supply Network with Multiple Water Sources

A water supply network is an essential part of industrial and urban water systems. The water intake in a conventional water supply network varies periodically over time, depending on the amount of available water resources and the demand at water sinks or water-using units. This paper establishes a super-structural mathematical model for the optimal design and operation of a multi-period water supply network with multiple water sources. It considers the flow rate fluctuation of raw water availability and the demand of water sinks during different periods. The influence of multi-period demand variation on technology and the capacity selection of desalination water stations is examined, which affects the overall cost of the water supply network. The operating cost penalty factor is introduced, which quantitatively clarifies how the network operating status influences the operating costs. The comparison results of three scenarios considering with and without multi-period variation of water demand verify the validity of the proposed model, i.e., for a municipal water price of 4 CNY·t−1 and penalty factor of 0.3, one reverse osmosis desalination unit of capacity 800 t·h−1 is selected. However, in the multi-period case, two reverse osmosis desalination units with capacities of 500 t·h−1 and 300 t·h−1 are selected. In both cases, the operating costs are different because of the different operating status of the network. The work can guide the design and operation of industrial and urban water supply networks.

Multi-criteria decision making and fairness evaluation of water ecological carrying capacity for inter-regional green development

Determining water ecological carrying capacity (WECC) is of great significance to ensure inter-regional green development. This study presents a comprehensive evaluation framework for WECC assessment in the Yangtze River Economic Zone (YREZ), China. Effects of water resources, socio-economic, and ecological elements on WECC can be evaluated based on multi-criteria decision analysis. Gini and unbalance coefficients are used for measuring the regional fairness between WECC and socio-economic development. Surface water production pressure (SWPP) and groundwater pollution risk (GPR) are further regarded as indicators for expressing water resources constraint on shale gas extraction in the YREZ. Results disclose that the average WECC level decreases from 0.439 in 2000 to 0.4007 in 2016, which is the opposite of the changing trend in the Beijing-Tianjin-Hebei Region. A high WECC level appears in Zhejiang (0.5126) with a good state, but that of Guizhou (0.3983), Anhui (0.3968), Hunan (0.3914), and Chongqing (0.3651) are at the alert state. The obstacle factors of WECC in the eastern YREZ mostly originate from socio-economic and water resource subsystems, while that in the middle and western YREZ mainly arise from water resources and ecological subsystems. Fairness analysis shows a well-matching characteristic between the overall WECC and socio-economic performances due to a majority of their Gini coefficients lower than 0.4, while a poor matching characteristic exists in terms of provincial differences owing to their varied unbalance coefficients, especially in Guizhou, Jiangsu, and Shanghai. Moreover, Chongqing with most of shale gas reserves is characterized by slight SWPP (1.0202) and GPR (0.0188), but the prospect of shale gas development in Sichuan is not optimistic due to its high SWPP (1.0846) and GPR (0.0647). Recycling of flowback and product waters can significantly lighten regional water resources pressure. This presented framework can be applied into many other Chinese cities (e.g., Beijing-Tianjin-Hebei Region) with slight modifications according to their actual situations for supporting water resource managers and government with decision making.

Analysis of the potential of reclaimed water utilization in typical inland cities in northwest China via system dynamics

Located in the hinterland of the Eurasian continent, the inland areas of northwestern China have an arid climate and are confronted with continuing challenges in water resources quantity and quality. Reclaimed water plays an important role in maintaining the sustainable use of urban water resources, especially in arid regions. In this paper, a system dynamics urban reclaimed water model (SDURWM) considering the status of arid regions in northwestern China was constructed. The supply and demand balance index (RWB) and the utilization efficiency index (RWUE) of reclaimed water were proposed as evaluation indicators. The potential of reclaimed water utilization (2016-2025) in three typical cities with similar natural environments and population sizes but with large economic differences were estimated by the SD model. Then the relevant values of reclaimed water quota, supply and resident awareness were adjusted within the range of 10%-20%. The predicted results from intervention demonstrate that the RWB of three cities will be closer or maintain to the ideal value, and that the RWUE will increase by about 0.1, compared with the non-intervention results. This indicates that a minor change of the targeted policies can invigorate the capacity of reclaimed water use in droughty cities. This paper provides some effective solutions for the government's planning of developing the potential of reclaimed water.