Hydrological response to climate change: The Pearl River, China under different RCP scenarios

Abstract

a b s t r a c tStudy region: The Pearl River, located in the south of China, is the second largest river in China in terms of streamflow. Study focus: The study aims to assess the impact of climate change on seasonal discharge and extreme flows. For the assessment we use the variable infiltration capacity (VIC) model driven by biascorrected results of five different climate models under the IPCC scenarios RCP4.5 and 8.5. New hydrological insights for the region: Previous studies focussed on annual discharge and extreme flood events in the basin. However it is also important to assess variations in low flow across the basin, because it is suffering from water shortage and salt water intrusion in the dry season. Results indicate a reduction in average low flow under the five climate models. The reduction varies across the basin and is between 6 and 48% for RCP4.5. River discharge in the dry season is projected to decrease throughout the basin. In the wet season, river discharge tends to increase in the middle and lower reaches and decrease in the upper reach of the Pearl River basin. The variation of river discharge is likely to aggravate water stress. Especially the reduction of low flow is problematic as already now the basin experiences temporary water shortages in the delta.

Potential Threats from Variations of Hydrological Parameters to the Yellow River and Pearl River Basins in China over the Next 30 Years

“…Increased runoff in August and September could increase flood risk during the latter stages of the flood season, but decreased runoff in the early flood season could reduce the risk of floods. This confirmed the likely drier and longer dry season in the Pearl River Basin under 1.5 and 2 • C global warming or the last thirty years of the 21st century under RCP4.5 and RCP8.5 [6,7]. As illustrated in Figure 6d, relatively smaller-sized floods (about 10,000-20,000 m 3 /s) would become more frequent, but current medium-sized floods (about 20,000-32,000 m 3 /s) and rare big flood (>43,000 m 3 /s) would become less frequent.…”

“…Another recent study projected an increase in runoff in a catchment within the Yellow River Basin, but slight decreases were projected in the Yangtze River and Pearl River Basins under 1.5 and 2 • C global warming [5,6]. In addition, alterations of seasonal discharge have also been projected [2,6,7]. In some basins, wet seasons are expected to become wetter and dry seasons drier in a world changing from 2 • C warming to 4 • C warming [8].…”

“…In some basins, wet seasons are expected to become wetter and dry seasons drier in a world changing from 2 • C warming to 4 • C warming [8]. River basins dominated by a monsoonal in annual runoff, seasonal runoff, and hydrological extremes during different time slices during the 21st century based on the IPCC AR5 [6,7,26]. However, few studies have focused on such changes during the short term (2021-2050), or on the impacts of climate change and population growth on base-scale water management.…”

Responses of runoff to historical and future climate variability over China

“…The impacts of climate change on water resources have been investigated in many regions of China, such as the Hanjiang 10 basin (Chen et al, 2007;Guo et al, 2009), the catchment of the Loess Plateau (Wang et al, 2013), the Qingjiang River basin (Chen et al, 2012), the Qiantang River basin (Xu et al, 2013b), the Songhuajiang River basin (Su et al, 2015), the southeastern Tibetan Plateau (Li et al, 2013b), the Pearl River basin (Yan et al, 2015), the Xin River basin (Zhang et al, 2016), the sub-catchments of the Yangtze and Yellow River basins (Xu et al, 2011), the Huang-Huai-Hai region (Lu et al, 2012), and ten major river basins in China . There is a large uncertainty involved in these impact studies,…”

Water use in a heavily urbanized delta : scenarios and adaptation options for sectorial water use in the Pearl River Basin, China

“…if the total water resources in the PRB decrease due to the climate change, building new reservoirs may not achieve the expected contribution in alleviating the salt intrusion problem. Previous study shows that low flow of the Pearl River could decrease by more than a half due to the climate change (Yan et al 2015). Thus, if the Datengxia-increased Q SD drops from the maximum anticipated value by 20% to 460 m 3 s-1, freshwater inlets number 8-16 may be affected again in November (Figure 3 -2).…”