The construction of water transfer projects can have a considerable impact on the operation of the receiving reservoir. This study investigates the change of the objective trade-offs in multiobjective reservoir operation problems due to the introduction of water transfer using a case study of the east-to-west water transfer project in northeastern China. Two optimization cases are constructed to analyze the trade-off changes: a base case with no water transfer that considers four objectives, i.e., minimizing industry water shortage, minimizing agriculture water shortage, minimizing water spillage, and maximizing ecological satisfaction; and a future postconstruction case that considers an additional objective to minimize the amount of water transferred. Results obtained from the case study show increasing water transfer substantially reduces the intensity of the competition between industrial and agricultural water shortages, and the objective trade-offs among water spillage, ecological satisfaction, and agricultural shortage index are substantially changed because of water transfer. In addition, the amount of water transferred with high efficiency regarding each objective is identified, and three solutions of different orders of magnitude in diverted water have been recommended for informed decision making considering efficiency and benefit. This study implies that many-objective visual analytics can be used to determine the optimal amount of water transferred in terms of water efficiency revealed in different objective trade-off spaces.

The essential problem for reservoir operation is how to deal with variability of inflow. The impacts of both climate change and human interferences on streamflow further complicate the issue of reservoir inflow variability. This paper presents a case study of a reservoir that has both natural inflow (NI) and controlled inflow (CI), and analyzes how CI, which can be a deterministic item, mitigates the effect of NI variability on reservoir operation. Through a case study of the Biliu River Reservoir in northeastern China, the following questions are addressed: (1) how will the combined NI and CI improve water supply reliability, and (2) can—and if so, how much—of the reservoir’s storage can be reduced without lowering water supply reliability with a certain level of CI? It is found that CI complements NI in terms of water supply reliability through a nonlinear relationship, as shown by an inverse S curve; the two turning points in the curve specify a range of CI with respect to the stochastic nature...

River basin simulation and multi-reservoir optimal operation have been critical for river basin management. Due to the intense interaction between human activities and river basin systems, the river basin model and multi-reservoir operation model are complicated with a large number of parameters. Therefore, fast and stable optimization algorithms are required for river basin management under the changing conditions of climate and current human activities. This study presents a new global optimization algorithm, named as heuristic dynamically dimensioned search with sensitivity information (HDDS-S), to effectively perform river basin simulation and multi-reservoir optimal operation during river basin management. The HDDS-S algorithm is built on the dynamically dimensioned search (DDS) algorithm; and has an improved computational efficiency while maintaining its search capacity compared to the original DDS algorithm. This is mainly due to the non-uniform probability assigned to each decision variable on the basis of its changing sensitivity to the optimization objectives during the adaptive change from global to local search with dimensionality reduced. This study evaluates the new algorithm by comparing its performance with the DDS algorithm on a river basin model calibration problem and a multi-reservoir optimal operation problem. The results obtained indicate that the HDDS-S algorithm outperforms the DDS algorithm in terms of search ability and computational efficiency in the two specific problems. In addition; similar to the DDS algorithm; the HDDS-S algorithm is easy to use as it does not require any parameter tuning and automatically adjusts its search to find good solutions given an available computational budget.

This paper investigates the influences of reservoir water level variations of the operation rule curves on different objectives, especially on ecological objectives. Five representative ecological objectives are selected besides industrial and domestic (I&D) and agricultural water supply objectives. They can reflect the impacts of reservoir operation on different attributes of ecological flow regime in the Biliuhe Reservoir case study, Northeastern China. Sensitivities of water supply and ecological objectives caused by water level variations of I&D and agricultural operation rule curves are analyzed by using a variance-based sensitivity analysis method – Sobol's method. Results show that impacts of individual water levels and their interactions on ecological objectives are very different. Also the ecological objectives do not always conflict with water supply objectives. This study provides new insights for reservoir managers to improve downstream aquatic ecosystem by adjusting water levels not only at individual time periods but also at some interacting time periods. Furthermore, it helps us better understand the influence mechanism of water level changes on different objectives, and provides guidance for the development of reservoir operation rules.

Many hydraulic projects such as reservoirs, ponds and paddy fields as well as soil and water conservation engineering projects have been constructed to improve utilization of water resources upstream of the Wudaogou station basin in Northeast China in recent years. As a result, the local hydrological characteristics of the basin and the flood runoff and process have been changed. These changes in the basin characteristics make basin hydrological forecasting more difficult. In order to model and assess this situation, the TOPMODEL, which includes the dynamic soil moisture storage capacity (DSMSC-TOPMODEL), is used in this study to simulate the flood impact of hydraulic projects. Furthermore, the Bayesian method is used to evaluate model parameter uncertainty and assess the TOPMODEL's performance over the basin. Flood simulation results show that accuracy is significantly improved when the stock version of TOPMODEL is replaced with DSMSC-TOPMODEL, with the qualified ratio of forecasting runoff yield increasing from 65% in the former to 88% in the latter. Moreover, these flood simulations are more suitable for helping observers visualize the process.