Spatiotemporal variation of flash floods in the Hengduan Mountains region affected by rainfall properties and land use

• DOI: 10.1007/s11069-021-05061-5
• Publication Date: 2021-10-30T12:02:40Z
• Authors: Xiaoyun Sun; Guotao Zhang; Jiao Wang; Chaoyue Li; Shengnan Wu; Yao Li
• Keywords: Physical geography; Monsoon; Flash flood; Flood Risk; Precipitation; Flooding (psychology); 01 natural sciences; Environmental science; Visual arts; Global Flood Risk Assessment and Management; Natural hazard; Meteorology; Flash (photography); Psychology; Water Science and Technology; 0105 earth and related environmental sciences; Climatology; Global and Planetary Change; Geography; Hydrology (agriculture); Geology; FOS: Earth and related environmental sciences; Flood myth; 15. Life on land; FOS: Psychology; Geotechnical engineering; Hydrological Modeling and Water Resource Management; Archaeology; 13. Climate action; Environmental Science; Physical Sciences; Global Drought Monitoring and Assessment; Psychotherapist; Art

Abstract Understanding the spatiotemporal characteristic of flash floods is significant for the reasonable and accurate identification of high-risk regions of disasters as well as future prediction of hydrological regimes. Therefore, this study collected time-series datasets (1979-2015) of historical flash flood events, rainfall, and land-use in the Hengduan Mountains region, China to characterize the spatiotemporal variation in flash floods affected by the change in rainfall and land-use. Using linear trend, a significant increase with 12 times/10a for flash flood events was found while 82% of events occurred in the flood season (June–August). They were closely related to the increase in frequency (3.5 d/10a) and magnitude (215.55 mm/10a) of heavy rainfall as well as the amplified artificial (999 km2). Affected by heavy rainfall due to climate change and human activity, significant periodic variations on the scales of 3-7a, 8-15a, and 21-31a were derived based on the Morlet wavelet analysis. Meanwhile, utilizing the standard elliptical difference, we identified the moving route of the gravity center of flash floods, with the direction from northwest to southeast. More recorded disasters generally were found in the south of the Hengduan Mountain region, where was mainly controlled by frequent rainstorms and the formation of more cropland and artificial with higher runoff potential. These findings can be an appropriate supplement for lack of understanding of the spatiotemporal dynamics of flash floods in the Hengduan Mountains region and could provide policymakers with evidence to identify high-risk areas which is difficult to cope with in the mountainous watershed.