Sagwal Sumit, Panda Sandeep, Sengupta Dipanwita, Shahrukh Mohd, Kumar Sohan, Kumar Anil, Dutt Som
Wadia Institute of Himalayan Geology, Dehradun, India, 248001.
Academy of Scientific and Innovative Research, Ghaziabad, India, 201002.
Environ Monit Assess. 2024 Dec 20;197(1):81. doi: 10.1007/s10661-024-13541-x.
The Himalayas experiences several cloudburst events due to its varied physiographical, geomorphological, and geological conditions and high rainfall. Uttarakhand is one of the Indian states circumscribed by the Himalayan ranges and has experienced a rise in the number of cloudburst catastrophes in the last few decades. These events cause substantial loss of life and property; however, very few studies have characterized these unpredictable cloudburst-induced flash floods in different regions of Uttarakhand. This study examines the geological and hydrological factors associated with the Raipur-Kumalda cloudburst event that occurred from 20 to 21 August 2022 in the Dehradun district of Uttarakhand. The resulting flash flood caused significant damage to roads, bridges, and settlements across the valley. The study aims to understand the geological and geomorphological controls of the event by analyzing the peak discharge and various flood parameters. The basin geomorphometry and rainfall intensity of the region reveal poorly developed drainage networks with low drainage density, steep slopes, rapid peak flows, a sharp peak hydrograph, and intense, concentrated rainfall, all of which worsen the impact of the flood. Various flood indices, including the rising curve gradient (K), flood magnitude ratio (M), and flood response time (TP), indicate a discharge 50 to 100 times higher during the event compared to the average monsoonal discharge. This study also discusses the role of mountain topography, climate, regional geology, and irreversible land use-land cover (LULC) changes associated with urbanization in intensifying the destruction.
由于其多样的自然地理、地貌和地质条件以及高降雨量，喜马拉雅地区经历了多次暴雨事件。北阿坎德邦是印度被喜马拉雅山脉环绕的邦之一，在过去几十年里，暴雨灾害的数量有所增加。这些事件造成了大量生命和财产损失；然而，很少有研究描述北阿坎德邦不同地区这些不可预测的暴雨引发的山洪。本研究考察了与2022年8月20日至21日发生在北阿坎德邦德拉敦地区的赖布尔-库马尔达暴雨事件相关的地质和水文因素。由此引发的山洪对山谷中的道路、桥梁和定居点造成了重大破坏。该研究旨在通过分析洪峰流量和各种洪水参数来了解该事件的地质和地貌控制因素。该地区的流域地貌测量和降雨强度显示，排水网络发育不良，排水密度低，坡度陡峭，洪峰流量迅速，流量过程线峰值尖锐，降雨强烈且集中，所有这些都加剧了洪水的影响。各种洪水指数，包括上升曲线梯度（K）、洪水量级比（M）和洪水响应时间（TP），表明该事件期间的流量比季风平均流量高出50至100倍。本研究还讨论了山地地形、气候、区域地质以及与城市化相关的不可逆转的土地利用-土地覆盖（LULC）变化在加剧破坏方面的作用。
