{"title":"Influence of reservoir impoundment on rainfall erosivity in the Three Gorges Reservoir region of China","authors":"Guang-Zhi Jiang, Jiaorong Lv, Xiu-bin He, Y. Bao","doi":"10.2166/nh.2022.038","DOIUrl":null,"url":null,"abstract":"\n New dammed reservoirs are expected to have a significant effect on the regional hydrocycle, but the detailed patterns may not be well understood. Regional climate change is likely to cause soil erosion uncertainty by affecting rainfall erosivity. In the present study, local precipitation and rainfall erosivity were investigated to determine the impounding influence of the Three Gorges Reservoir. Daily erosive precipitation, from 1980 to 2020, was categorized into four intensity levels (light, moderate, heavy, and very heavy), as well as extreme rainfall, to understand their contribution to erosivity. It was found that the impoundment significantly affected local precipitation, with both heavy precipitation and the relative erosivity showing a substantial declining trend (Sen's slope = 2.141, p < 0.05). The Mann–Kendall test indicated an abrupt change point around the year 2002, evidencing the effect of the reservoir impoundment (since 2003). Reservoir impoundment redistributed the intensity levels of erosive precipitation, leading to a 24.3% decrease in the erosivity of heavy precipitation and an 8.2% increase in the moderate category. The unimodal distribution of monthly precipitation was altered to a bimodal distribution with peaks in July and September, resulting in a longer but lower-risky erosion period of high concern. The fluctuations of Rx1day and Rx5day were obviously flattered after impoundment, with a 54.2% peak reduction in relative erosivity on average. Results indicated that heavy rainfall (including extreme rainfall) was reduced, and annual precipitation and erosivity both had a more even seasonal distribution following reservoir impoundment.","PeriodicalId":55040,"journal":{"name":"Hydrology Research","volume":null,"pages":null},"PeriodicalIF":2.7000,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hydrology Research","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.2166/nh.2022.038","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"Environmental Science","Score":null,"Total":0}
引用次数: 0
Abstract
New dammed reservoirs are expected to have a significant effect on the regional hydrocycle, but the detailed patterns may not be well understood. Regional climate change is likely to cause soil erosion uncertainty by affecting rainfall erosivity. In the present study, local precipitation and rainfall erosivity were investigated to determine the impounding influence of the Three Gorges Reservoir. Daily erosive precipitation, from 1980 to 2020, was categorized into four intensity levels (light, moderate, heavy, and very heavy), as well as extreme rainfall, to understand their contribution to erosivity. It was found that the impoundment significantly affected local precipitation, with both heavy precipitation and the relative erosivity showing a substantial declining trend (Sen's slope = 2.141, p < 0.05). The Mann–Kendall test indicated an abrupt change point around the year 2002, evidencing the effect of the reservoir impoundment (since 2003). Reservoir impoundment redistributed the intensity levels of erosive precipitation, leading to a 24.3% decrease in the erosivity of heavy precipitation and an 8.2% increase in the moderate category. The unimodal distribution of monthly precipitation was altered to a bimodal distribution with peaks in July and September, resulting in a longer but lower-risky erosion period of high concern. The fluctuations of Rx1day and Rx5day were obviously flattered after impoundment, with a 54.2% peak reduction in relative erosivity on average. Results indicated that heavy rainfall (including extreme rainfall) was reduced, and annual precipitation and erosivity both had a more even seasonal distribution following reservoir impoundment.
期刊介绍:
Hydrology Research provides international coverage on all aspects of hydrology in its widest sense, and welcomes the submission of papers from across the subject. While emphasis is placed on studies of the hydrological cycle, the Journal also covers the physics and chemistry of water. Hydrology Research is intended to be a link between basic hydrological research and the practical application of scientific results within the broad field of water management.