Variation characteristics of hydrological response to water conservancy construction in the Qinhe River Basin of the Loess Plateau, China

Abstract

Investigating the response characteristics of various hydrological factors to water conservancy projects area in basin and evaluating their impact on the ecological environment are crucial for ecological protection and restoration on the Loess Plateau, China, with a complex environment. In this study, we employed a geomorphology‐based hydrological model to simulate the hydrological elements of the Qinhe River Basin on the Loess Plateau. We explored the response characteristics of the water cycle and hydrological processes to the construction of reservoirs in the basin. Additionally, we also examined multiyear changes in peak flood volume and sediment discharge during flood seasons influenced by reservoirs. The sub‐basins hosting reservoirs initialled an increase in evaporation, followed by a decrease. During the change periods, both runoff and soil water decreased, but remained higher than the mean values for the basin during the same period. The Normalized Difference Vegetation Index of sub‐basins associated with five reservoirs was obviously higher than the mean value for the basin during the same period. The peak flood volume and sediment discharge in the basin were characterized by decreasing trends, with the latter showing weak sustainability. The value of each index for a sub‐basin associated with a reservoir was higher than the average value for the basin. The construction and operation of reservoirs had a positive impact on the ecology of the basin. Water and soil conservation measures, including sediment regulation and storage using reservoirs, effectively decreased water hazard and soil erosion in the basin. This study provides a scientific basis for the construction of water conservancy projects and ecological governance in the basin.

Assessing the Spatiotemporal Variations in the Hydrological Response of the Qin River Basin in Loess Plateau, China

“…This directly led to the intensification of soil erosion and flood disasters in the region. Therefore, since the 1970s, large-scale soil and water conservation construction projects have been carried out in the basin [11,35].…”

“…Model input data include basic geographic information data (e.g., DEM, river network), daily dynamic meteorological data (e.g., precipitation, temperature), annual dynamic LULC data, and annual NDVI data. The parameter values implemented in the hydrological model have already been validated and are based on the previous research of Guo et al [11,29], as reported in Table 1. In this study, the period from 1971 to 1976 was selected as the calibration period, and the period from 1976 to 1981 was selected as the validation period.…”

“…As an important agricultural area, the natural scarcity of water resources is a challenge. In addition, the basin ecology is easily disrupted, and the regional hydrological processes are highly complex [10,11]. Therefore, the Loess Plateau is an ecologically sensitive area in which development must be carefully planned.…”

“…In the latter 30 years of the 20th century, many soil and water conservation measures were implemented in the basin while agricultural land and urban expansion developed. These 30 years represent a period of rapid changes within the environment of this basin [11,35]. The Qin River basin represents the overall characteristics of the Loess Plateau to a certain extent in that it has a complex terrain and is subject to strong human interference [11].…”

“…These 30 years represent a period of rapid changes within the environment of this basin [11,35]. The Qin River basin represents the overall characteristics of the Loess Plateau to a certain extent in that it has a complex terrain and is subject to strong human interference [11]. Therefore, accurately understanding the evolution law of water resources in the region and revealing the influence of hydrological driving factors has become a critical issue requiring solutions.…”