Climate Change Impacts on Drought-Flood Abrupt Alternation and Water Quality in the Hetao Area, China

Yuheng Yang,Jun Ma,Wuxia Bi,Ting Xu,Dengming Yan,Baisha Weng

doi:10.3390/w11040652

Abstract

Drought-flood abrupt alternation (DFAA) is an extreme hydrological phenomenon caused by meteorological anomalies. To combat the climate change, the watershed integrated management model—Soil and Water Assessment Tool model (SWAT)—was used to simulate DFAA, total nitrogen (TN) and total phosphorus (TP) from 1961 to 2050, based on measured precipitation data in the Hetao area and the downscaled Representative Concentration Pathways (RCPs) climate scenarios. In the future, the increase in temperature and the increase in extreme precipitation will aggravate the pollution of water bodies. Results indicate that the risk of water quality exceeding the standard will increase when DFAA happens, and the risk of water quality exceeding the standard was the greatest in the case of drought-to-flood events. Results also indicate that, against the backdrop of increasing temperature and increasing precipitation in the future, the frequency of long-cycle and short-cycle drought-flood abrupt alternation index (LDFAI, SDFAI) in the Hetao area will continue to decrease, and the number of DFAA situations will decrease. However, the zone of high-frequency DFAA situations will move westward from the eastern Ulansuhai Nur Lake, continuing to pose a risk of water quality deterioration in that region. These results could provide a basis for flood control, drought resistance and pollution control in the Hetao and other areas.

Highlights

In 2018, the Intergovernmental Panel on Climate Change (IPCC) pointed out that the global average temperature has risen by nearly 1.5 ◦ C, and it is predicted that it will increase by another1.1–6.4 ◦ C in 2100 [1,2]
We believe that under the premise of the reduction in Drought-flood abrupt alternation (DFAA) events in the Hetao area, there are three reasons for the increasing water pollution risk: (1) With the increase in precipitation processes, rainwater and runoff pass through the ground, and the pollutants accumulated on the surface are carried into the water body, causing pollution of surface water and even groundwater within the drainage area, especially in the vicinity of farmland or industrial land, which will form serious non-point source pollution [41]
Trend in the Hetao area, the spatial and temporal distribution characteristics and the risk of water pollution caused by DFAA

Summary

Introduction

In 2018, the Intergovernmental Panel on Climate Change (IPCC) pointed out that the global average temperature has risen by nearly 1.5 ◦ C, and it is predicted that it will increase by another1.1–6.4 ◦ C in 2100 [1,2]. In 2018, the Intergovernmental Panel on Climate Change (IPCC) pointed out that the global average temperature has risen by nearly 1.5 ◦ C, and it is predicted that it will increase by another. DFAA is a type of extreme weather affected by climate change [7]. It refers to drought in a certain period of time and flooding in another period, an alternating occurrence of droughts and floods [8]. DFAA research increased in the 20th century. During this period, there were more extensive and

Methods

Results

Discussion

Conclusion