Reservoir Regulation for Ecological Protection and Remediation: A Case Study of the Irtysh River Basin, China

Abstract

Hydrological processes play a key role in ecosystem stability in arid regions. The operation of water conservancy projects leads to changes in the natural hydrological processes, thereby damaging the ecosystem balance. Ecological regulation is an effective non-engineering measure to relieve the influence of water conservancy projects on ecosystems. However, there are still some problems, such as an insufficient understanding of hydraulic processes and difficulty evaluating the application effects. In this study, the theory of ecological reservoir regulation coupled with hydrological and ecological processes was examined and ecological protection and remediation were investigated using the valley forests and grasslands in the Irtysh River Basin as a case study. The results demonstrated that (1) to meet the demand of the hydrological processes in the valley forests and grasslands, in terms of ecological regulation, the peak flow and flood peak duration of the reservoir, named 635, in the Irtysh River Basin should be 1000 m3 s−1 and 168 h, respectively, and the total water volume of ecological regulation should be 605 million m³. Ecological regulation can guarantee that the floodplain range reaches 64.3% of the core area of ecological regulation and the inundation duration in most areas is between 4–8 d; (2) an insufficient ecological water supply would seriously affect the inundation effects. The inundation areas were reduced by 2.8, 5.1, 10.3, and 19.3%, respectively, under the four insufficient ecological water supply conditions (528, 482, 398, and 301 million m3), and the inundation duration showed a general decreasing trend; (3) the construction of ecological sluices and the optimization of the reservoir regulation rules could effectively relieve the influences of an insufficient ecological water supply. At water supply volumes of 528 and 482 million m3, the regulation rules should assign priority to the flood peak flow; at water supply volumes of 398 and 301 million m3, the regulation rules should assign priority to the flood peak duration. Consequently, this study provides a reference for ecological protection in arid regions and the optimization of ecological regulation theories.

Application of a Linked Hydrodynamic–Groundwater Model for Accurate Groundwater Simulation in Floodplain Areas: A Case Study of Irtysh River, China

“…During the model validation stage, the NSE values are 0.93, 0.85, and 0.94 for the respective sites, which further confirmed the rationality of the parameter values. Additionally, the accuracy of the model is further confirmed by comparing the inundation area derived from the model simulation results with remote sensing images, showing an error of less than 15% [52]. Moreover, the comparison between the calculated and observed hydrographs for the wet periods in 2016 and 2017 at the three sites (Burqin, Sarbulak, Halagou Mudao Bridge) is depicted in Figure 8, demonstrating a strong agreement.…”

“…The time step and Manning's roughness coefficient of the hydrodynamic model plays a crucial role in determining the simulation accuracy, and their values can be determined during the model calibration phase by trial and error. A comprehensive description of the model establishment, calibration, validation, and application of TELEMAC-2D in the study area can be found in reference [52].…”

“…These results collectively demonstrate the high precision of the 2D hydrodynamic model in simulating flood dynamics. For a more comprehensive understanding of the calibration and validation process of the 2D hydrodynamic model in the study area, please refer to [52]. Considering the occurrence of two major floods in 2017, a higher level of model accuracy is required.…”

Macrobenthic Community Structure and Water Quality Evaluation in Ulungu River Basin (Northwest China)

“…However, previous studies have found [46] that the pollution level of the upper reaches of the Irtysh River is low, and the cross-border runoff does not have the characteristics of serious pollution. This may be due to increased rainfall and reduced permafrost volume, coupled with the effective operation of large dams and reservoirs in the Irtysh River Basin in China and the implementation of water-saving technologies, which ensured the water level in the basin [47] and weakened the impact of polluted water in the Ulungu River, ensuring the health of the river. However, the water quality of the Irtysh River in East Kazakhstan is poor, which may be mainly due to heavy metal and nuclear pollution caused by previous industries in the area [48].…”

Variations in precipitation and temperature in Xinjiang (Northwest China) and their connection to atmospheric circulation

“…Within the IRB, the Irtysh River is the only river in China that flows into the Arctic Ocean. It originates from the southwestern slope of the Altai Mountains in China, and its water volume ranks second in XJ following the Ili River (Liu et al, 2017;Wang et al, 2022). The NSTM consists of small-and medium-sized rivers and is the most economically developed area in XJ, with the sharpest contradiction between the supply and demand of water resources (Sun et al, 2022).…”