Impacts of Climate Change and Land Use/Cover Change on Streamflow in Beichuan River Basin in Qinghai Province, China

Abstract

Climate change (CC) and land use/cover change (LUCC) are the main drivers of streamflow change. In this study, the effects of CC and LUCC on streamflow regime as well as their spatial variability were examined by using the Distributed Hydrology Soil Vegetation Model (DHSVM) for the Beichuan River Basin in the northeast Tibetan Plateau. The results showed that CC increased annual and maximum streamflow in the upstream but decreased them in the downstream. CC also enhanced minimum streamflow in the whole river basin and advanced the occurrence of daily minimum streamflow. Temperature change exerted greater influence on streamflow regime than wind speed change did in most situations, but the impact of wind speed on streamflow reflected the characteristics of accumulative effects, which may require more attention in future, especially in large river basins. As for LUCC, cropland expansion and reservoir operation were the primary reasons for streamflow reduction. Cropland expansion contributed more to annual mean streamflow change, whereas reservoir operation greatly altered monthly streamflow pattern and extreme streamflow. Reservoir regulation also postponed the timing of minimum streamflow and extended durations of average, high, and low streamflow. Spatially, CC and LUCC played predominant roles in the upstream and the downstream, respectively.Hydrological response to CC and LUCC at global or large basin scales help us to understand the general condition of the impacts [7-9]. However, significant spatiotemporal variations of CC and LUCC in different regions indicate that regional or local responses deviate from the general conditions. Further, understanding regional or local hydrological responses is especially relevant to everyday people's life, as the knowledge can be directly used in water resources management [10-16]. Regional or localized knowledge is especially important for the Tibetan Plateau, which hosts the numerous smalland meso-scale headwaters of large rivers in Asia, including the Yellow, the Yangtze, the Mekong, the Indus, the Salween, and the Tarim, [17][18][19][20].Quite a few studies on CC and LUCC impacts on hydrology have substantially sprung up in the last 50 years [7]. The earliest review articles examined the LUCC effects on the basis of paired catchment studies [21-23], but the approach was only suitable for small catchments (<10 km 2 ) that have uniform vegetation cover and the same climate, contributing little to water resource management, which usually covers varied land cover types and climate conditions [7]. Recent studies employed statistical methods [24][25][26] and hydrological models [10,17,20,27,28] to assess the impacts from both CC and LUCC. Statistical methods are simple and effective [29], but reveal few physical mechanisms. Moreover, this method is generally applied to describe interannual and interdecadal hydrological processes due to the foundation of equations based on annual or multi-year average [30]. Physically-based hydrological models, especially distributed hydrologi...

Trend Analysis of Annual and Seasonal River Runoff by Using Innovative Trend Analysis with Significant Test

“…The climate in the lake area is mild and dry. The average temperature in July is [15][16][17][18][19][20][21][22][23][24][25] • C, and the average temperature in January is −6 • C. The Lake Issyk-Kul drainage basin occupies a surface area of 22,080 km 2 , and there are 118 large and small rivers with a surface runoff of about 36.7 × 10 8 m 3 [62]. The main river flows are Chong-Koi-Suu, Cholpon-Ata, Chong-Ak-Suu, Ak-Suu, Chong-Uryukty, Pzhergalan, Ak-sai, Tossor, Ton, Dzhuuku, Tamga, Karakol, and Chong-Kyzyl-Su [63].…”

Land cover change and its implication to hydrological regimes and soil erosion in Awash River basin, Ethiopia: a systematic review

“…Among many factors, climate change and anthropogenic activity (Gao & Ruan, 2018), the intensity of rainfall, and geomorphology are responsible for flood disaster (Sˇpitalar et al, 2014) and unnatural causes, including breach of dams and overtopping banks. Liu et al (2020) have noted that climate change and LC (cropland expansion and reservoir regulation) on the response of streamflow patterns. The decrease of the surface roughness consequently increases the surface flooding.…”

A rapid flood inundation model in the floodplain area due to an extreme rainfall event

“…As of 19 February 2021, some parts of East Jakarta, was heavily flooded because of extreme rainfall event. Land use/land cover change (LUCC) in the city is causing the reduction of reservoir areas, which will escalate flood hazard in distinctive places [11]. Rapid development consequently changing the former land use into built-up areas for industrial, residential, and commercial purposes.…”