Studies on urban climatic mapping and local climate zones are urgently needed due to rapid urbanisation in China, to identify and predict serious air pollution problems and occurrence of urban heat islands, for sustainable urban planning. The study of wind environment, especially measurements of wind data on the urban scale, is important to the climate mapping and investigation of air pollution and heat island events. In this paper, we introduce a measurement method for the urban-scale wind environment, which combines measurements conducted at the stationary reference station with those at portable/mobile stations. Data collected from portable/mobile stations were normalised with respect to wind data measured at the stationary reference station. Three criteria for the selection of the stationary reference station were compared according to the land-use and distance to the portable/mobile stations. The background meteorological station was selected as the stationary reference station for data normalisation and was found to be the most appropriate. The normalisation method for wind data was used to analyse the measured wind data at portable/mobile stations. Clear differences were observed between measured and normalised average wind speeds. The normalised wind was used in the urban wind environment mapping. The objective of the mapping is to assess the ventilation potential of the urban canopy layer, to help the urban climate mapping and to inform future sustainable urban planning.

Ecological flow is an important basis for maintaining the structure and function of river ecosystems, and ensuring the sustainable development of economies and societies in river basins. In order to solve the problems of unclear concepts of ecological flow, difficulty in adapting to dynamic changes in demands, and the hydrological conditions and poor operability of calculated results of a practical application, a variable interval analysis method (VIAM) was proposed to calculate the ecological flow. The method comprehensively considered a variety of variable factors, such as spatial–temporal scale changes, hydrological condition changes, ecological service object changes, and calculation method changes. On the basis of a relatively fixed ecological base flow, a variable lifting amount was added to determine the ecological flow, and the ecological flow was a variable interval. Taking the Wei River as an example, the VIAM was validated and applied. With the support of a knowledge visualization integrated platform, the ecological flow simulation system of the Wei River was constructed. The results show that: (1) the VIAM makes the ecological flow calculation more scientific and reasonable, and the ecological flow of the Wei River from the upper reaches to the lower reaches increases gradually under the influence of water inflow, sewage discharge, and erosion and deposition of sediment, and the annual total water demand of the upper limit of ecological flow in a dry year is 1.04 billion m³, 1.63 billion m³, 2.29 billion m³, 4.09 billion m³, and 4.66 billion m³; (2) the variable interval is used to describe the ecological flow, which has strong applicability and operability; (3) the simulation system can quickly adapt to the demand changes in practical application, and provide visual decision support for managers. The VIAM provides new ideas and references for comprehensively promoting the control of the ecological flow.

The objectives of flood control, power generation, water supply and ecology for reservoir operation are neither completely coordinated nor completely opposed, and its optimal operation and decision-making is very complicated. This study proposed a method of multi-objective optimization and multi-attribute decision making for reservoir operation (MODRO). The correlation analysis method was used to analyze the competitive relationship among the extracted objectives, and the multi-objective optimal operation model was constructed. The NSGA-II-SEABODE algorithm was applied to solve the MODRO problem. The objective extraction, model construction, optimization solution and scheme selection were coupled to form a multi-objective optimization and multi-attribute decision making method with the whole process of “Objective-Modeling-Optimization-Selection”. Huangjinxia Reservoir, which is located in Shaanxi, China, was selected as the case study. The results show that: (1) Quantifying the degree of conflict among objectives makes the construction of the multi-objective optimal operation model more reasonable. (2) The NSGA-II-SEABODE algorithm are used to obtain the decision-making scheme, which provides decision-making basis for managers. (3) For Huangjinxia Reservoir, water diversion is negatively related to power generation and ecology, and power generation is positively related to ecology. The results can promote the efficient utilization of water resources, improve the comprehensive benefits of reservoirs, and provide decision-making support for actual reservoir operation.

In traditional ecological operation, it is difficult to coordinate the balance among the interests of stakeholders, and stakeholders find it difficult to accept the operation scheme. To address these problems, this study proposed a method of multi-stakeholder coordinated operation of reservoir (MSCOR). By comprehensively considering the interest demands of stakeholders, the multi-stakeholder interval coordination mechanism (MSICM) for reservoir operation was established. The multi-stakeholder coordinated operation model (MSCOM) was constructed. The multi-stakeholder solution algorithm based on the MSICM, the non-dominated sorting genetic algorithm II, and the approach of successive elimination of alternative schemes based on the k-order and p-degree of efficiency (MSIC-NSGA-II-SEABODE) were applied to solve the MSCOR problem. The coordination mechanism, model construction, multi-stakeholder optimization, and multi-attribute decision making were coupled to establish a multi-stakeholder coordinated operation method, comprising the whole process of mechanism–modeling–optimization–decision making. Taking Baojixia Reservoir as an example, the performance of the coordinated operation method was compared with that of the traditional optimal operation method, and the relationship between the irrigation benefits and ecological benefits of the reservoir was explored. The results show that: (1) On the premise of the same satisfaction degree of basic irrigation interests, the ecological AAPFD value of coordinated operation decreased by 0.184, 0.469, and 0.886 in a normal year, dry year, and extraordinary dry year, respectively. The effect of coordinated operation on balancing various stakeholders was more obvious with the decrease in water inflow. (2) The MSICM ensures that the multi-stakeholder operation of the reservoir conforms to the principles of comprehensiveness, balance, and sustainability. (3) The coordination scheme obtained by the MSIC-NSGA-II-SEABODE algorithm is more reasonable and feasible. The research results provide a new idea and method to address the MSCOR problem.

Socioeconomic drought is one of the most frequent natural disasters in the world and is closely related to human life. The main cause of socioeconomic drought is the contradiction between water supply and demand; hence, as local reservoirs play a major role in improving water supply and coping with extreme climate, it is reasonable to estimate socioeconomic drought based on reservoir operations. The multivariate standardized reliability and resilience index (MSRRI) is utilized to evaluate socioeconomic drought, considering the characteristics of reservoir management and storage water resources. Therefore, with the MSRRI, this study takes the Heihe River Basin in northwestern China, which is controlled by two reservoirs dominating the upstream and downstream regions, as a case study to reveal the evolution characteristics of socioeconomic drought in the basin and the external impacts of climate variability. The results showed that (1) the drought intensity in the up-midstream region is stronger than that in the downstream region; in view of the hysteresis in the downstream region, the occurrence of drought in the up-midstream region could be regarded as an early warning to implement preventive measures in the downstream region; (2) an increasing trend in socioeconomic drought throughout the basin exists on both monthly and annual scales, which indicates that the increasing possibility of drought should be effectively addressed; (3) cross wavelet analysis indicated that the large-scale climate indices contribute to the variations in the socioeconomic droughts throughout the basin, indicating that climate variability may provide a reference for managers to deal with socioeconomic drought in the HRB.

The parallel reservoirs in the upper reach of the Hanjiang River are key projects for watershed management, development, and protection. The optimal operation of parallel reservoirs is a multiple-stage, multiple-objective, and multiple-decision attributes complex decision problem. Taking Jiaoyan–Shimen parallel reservoirs as an example, a method of multi-objective optimal operation decision of parallel reservoirs (MOODPR) was proposed. The multi-objective optimal operation model (MOOM) was constructed. The new algorithm coupling NSGA-II, TOPSIS, and GCA was used to solve the MOODPR problem. The method of MOODPR was formed by coupling problem identification, model construction, an optimization solution, and scheme evaluation. The results show that (1) combining the Euclidean distance with the grey correlation degree to construct a new hybrid closeness degree makes the multi-attribute decision making method more scientific and feasible. (2) The NSGA-II-TOPSIS-GCA algorithm is applied to obtain decision schemes, which provide decision support for management. (3) It can be seen from the Pareto chart that for the Jiaoyan–Shimen parallel reservoirs, the comprehensive water supply was negatively related to ecology. (4) The comprehensive water supply and ecological AAPFD value in the extraordinarily dry year was 4.212 × 10⁸ m³ and 4.953. The number of maximum continuous water shortage periods was 4 and 6. The maximum ten-day water shortage was 4.46 × 10⁷ m³ and 2.3 × 10⁶ m³. The research results provide technical support and reference value to multi-objective optimal operation decisions for parallel reservoirs in the upper reach of the Hanjiang River.