Assessing the Impacts of Future Climate and Land-Use Changes on Streamflow under Multiple Scenarios: A Case Study of the Upper Reaches of the Tarim River in Northwest China

Abstract

Climate change and land use/cover change (LUCC) are two major factors that alter hydrological processes. The upper reaches of the Tarim River, situated in the northwest region of China, experience a dry and less rainy climate and are significantly influenced by human activities. This study comprehensively assessed the impacts of individual and combined climate changes and LUCCs on streamflow. Three general circulation models (GCMs) were utilized to predict future climate changes under three shared socioeconomic pathways (SSP119, SSP245, and SSP585). Cellular Automata–Markov (CA–Markov) was employed to predict future LUCC under three scenarios (i.e., ecological protection, historical trend, and farmland development). Streamflow for the period 2021–2050 was simulated using the calibrated MIKE SHE model with multiple scenarios. The results showed that from 2021 to 2050, increments in both average annual precipitation and average annual temperature under the three SSPs were predicted to lead to an increased streamflow. In comparison to the conditions observed in 2000, under three LUCC scenarios for 2030, the grassland area decreased by 1.04% to 1.21%, while the farmland area increased by 1.97% to 2.26%, resulting in reduced streamflow. The related changes analysis indicated that the variation in streamflow during winter is most significant, followed by spring. The study predicted that climate change would increase streamflow, while LUCC would decrease it. Due to the greater impact of LUCC, considering the combined effect of both factors, runoff would decrease. The contribution analysis indicated that climate change contributed between −7.16% and −18.66%, while LUCC contributed between 107.16% and 118.66%.

Response of Streamflow to Future Land Use and Cover Change and Climate Change in the Source Region of the Yellow River

“…Most studies considering future changes in the upper Yellow River basin are limited to climate change [34,35] or focus solely on the changes in a particular meteorological element [36]. However, there have been studies in other regions that comprehensively consider both land use and cover change (LUCC) and climate change in future predictions [24,[37][38][39]. Our research contributes to the study of the extremely scarce future hydrological processes in the SRYR [21,40].…”

“…Due to the complexity of explaining the mechanisms underlying the impact of future environmental changes on streamflow through statistical analysis, current research on future streamflow mainly relies on hydrological models driven by future climate data for simulation. Several models have been used to predict future hydrological processes, including the SWAT model [18][19][20][21], the VIC model [22,23], the MIKE SHE model [24], and the Budyko model [25,26]. Compared to the Budyko model, hydrological models often require a large amount of forcing data.…”

“…The VIC model can reflect changes in vegetation quality, and the significant differences between considering and not considering dynamic LAI display pronounced trends [28]. However, the SWAT and MIKE SHE models characterize LUCC in terms of land use type, which cannot consider changes in vegetation growth status [12,24]. Actually, the DHSVM can also consider changes in vegetation quality and has been widely used in hydrological simulations under climate change and LUCC.…”

Evaluation of the Offsets of Artificial Recharge on the Extra Run-Off Induced by Urbanization and Extreme Storms Based on an Enhanced Semi-Distributed Hydrologic Model with an Infiltration Basin Module

“…On the other side, climate change, in connection with declining impervious areas due to urbanization, will affect surface hydrological processes, particularly surface runoff [16][17][18][19]. Previous studies have investigated the influence of climate change and urbanization on surface runoff, projecting an increase in streamflow resulting from the combined impact of these factors [16][17][18].…”

“…On the other side, climate change, in connection with declining impervious areas due to urbanization, will affect surface hydrological processes, particularly surface runoff [16][17][18][19]. Previous studies have investigated the influence of climate change and urbanization on surface runoff, projecting an increase in streamflow resulting from the combined impact of these factors [16][17][18]. For instance, Franczyk and Chang [16] utilized the AVSWAT hydrological model in the Portland metropolitan area, Oregon, USA, and projected a 1.2 • C temperature increase and a 2% increase in precipitation by 2040.…”