Jiahui Zhang

Water demand has increased due to population growth and rapid socioeconomic development, creating conflicts between human activities and water resources and having a substantial impact on the balance between blue and green water supplies. Existing study lacks a spatial perspective to examine the inherent relationship between blue and green water supply and demand, particularly in terms of geographical differentiation characteristics and rational allocation of blue and green water supply–demand balance in inland river basins. Using the Taolai River Basin as a case study, this research uses the distributed hydrological model SWAT from a blue–green water resources viewpoint to simulate the spatiotemporal distribution features of blue and green water resources at the sub-basin scale from 2002 to 2021. The supply and demand balance relationship of blue and green water resources within the basin was investigated, an assessment index system for water resource security was developed, and the realizable potential of blue water resources was quantified using various indicators. The findings show that during the study period, the average annual green water resources in the Taolai River Basin were 1.95 times greater than blue water resources, making green water the most abundant component of regional water resources. Spatially, both blue and green water resources showed considerable latitudinal zonality, with a declining tendency from south to north and very consistent distribution patterns. Blue water resources showed high geographic variability, with a safety index more than one, suggesting that supply–demand imbalances were most concentrated in the upper and intermediate ranges of the irrigated region, as well as the desert zone, where safety levels were relatively low. In contrast, green water resources had a safety score ranging from 0.7 to 1.0, indicating great overall safety and negligible regional variability. During the research period, the average annual theoretical transferable blue water resources were 4.06 × 108 m³, based on cross-regional water resource allocation potential analysis. This reveals tremendous potential for enhancing regional water resource allocation, hence providing substantial support for effective water consumption within the Taolai River Basin and regional economic growth. In conclusion, the assessment method developed in this work provides a solid foundation for improving water resource allocation and sustainable management in river basins. It provides technical assistance in the construction of water network systems in inland river basins, which is critical in establishing reasonable water resource distribution across various areas within these basins.

Sustainable urban water management has emerged as a pressing issue that has to be resolved immediately due to the increasing severity of water environment issues brought on by urbanization. While the seasonal storage pool is an important part of urban stormwater management, optimizing the ecological dynamics of its water ecosystem is of great significance for maintaining the quality of the regional water environment. Currently, the majority of research on seasonal rivers focuses on the exploration of ecological restoration programs and governance evaluation research. As a result, there is relatively little research on the ecosystem restoration of species change process and community change law. This study used the AQUATOX ecological modeling technique to simulate and forecast the seasonal dynamics of aquatic biological communities in the recently built terraced storage ponds in the upper reaches of the Shuifu River. The study’s findings showed that the simulated and real observed values of the water quality indicators were highly consistent, and the model’s fitting efficiency, which varied from 0.73 to 0.98, showed that the simulation results and the real situation agreed well. Subsequent investigation revealed that if the transfer ponds are run until 2026, the aquatic biomass increases by 0.02–16.24%. The summer and fall seasons showed a larger biomass than the winter and spring months between 2023 and 2026. Additionally, seasonal fluctuations had a substantial impact on the impoundment’s biodiversity. In particular, populations of phytoplankton and zooplankton rise quickly in the spring, reach their maximum in the summer and then progressively decline in the fall and winter. Despite their relative stability, fish populations did exhibit minor seasonal variations. Redundancy analysis revealed that the primary drivers affecting the seasonal succession of the biological community in the storage pond were environmental parameters such as water temperature (WT), five-day biochemical oxygen demand (BOD5), total phosphorus (TP) and total nitrogen (TN). Therefore, a scientific foundation for the logical optimization of the water ecosystem function of the urban seasonal storage pond is provided by the targeted optimization of these environmental factors to support the stable and healthy development of the water ecosystem of the storage pond. This is crucial for advancing the sustainable management of the urban water environment.

The numerical simulation and field investigation of solid-liquid two-phase flow are carried out in a large-scale forward intake forebay with various diffusion angles at the Jingtaichuan Pumping Irrigation Project in Gansu Province, China. The purpose is to investigate the properties of sediment deposition in the pumping station forebay. The results indicate that the low-sediment concentration area is in the forebay’s centre, whereas the high-sediment is near the two side walls flanks. The sediment concentration increases dramatically from the centre to the sides. Both the high-sediment concentration area and the sediment concentration increase with water depth. The forebay’s narrowing diffusion angle causes the high-concentration area to gradually decrease while the low-concentration area gradually increase. Furthermore, the amount of siltation and sediment deposition efficiency decrease, resulting in a large increase in forebay sediment concentration and sedimentation efficiency. The sediment concentration and water flow velocity reveal a quadratic polynomial relationship. This study can provide a guide and reference for the design and construction of comparable large-scale pumping station forebays.