Downstream Decreasing Channel Capacity of a Monsoon-dominated Bengal Basin River: A Case Study of Dwarkeswar River, Eastern India

作     者：MALIK Sadhan PAL Subodh Chandra MALIK Sadhan;PAL Subodh Chandra

作者机构：Department of GeographyUniversity of BurdwanBurdwan 713104West BengalIndia 

出 版 物：《Chinese Geographical Science》 (中国地理科学（英文版）)

年 卷 期：2020年第30卷第5期

页      面：900-920页

核心收录：

学科分类：0303[法学-社会学] 08[工学] 0708[理学-地球物理学] 081501[工学-水文学及水资源] 0705[理学-地理学] 0815[工学-水利工程] 0813[工学-建筑学] 0704[理学-天文学] 0833[工学-城乡规划学] 

基　　金：the auspices of the University Grants Commission(No.21595/(NET-DEC.2013) F.15-6(DEC.2013)) 

主　　题：bankfull channel width bankfull discharge Dwarkeswar River flat alluvial plain channel degradation overbank flow and flood 

摘      要：Downstream changes in channel morphology and flow over the ephemeral Dwarkeswar River in the western part of the Bengal Basin, eastren India were investigated. The river stretches from the Proterozoic Granite Gneiss Complex to the recent Holocene alluvium, forming three distinctive geomorphological regions across the river basin: the pediplane and upper and lower alluvial areas. Sixty cross-sections from throughout the main trunk stream were surveyed and the bankfull width, depth, cross-sectional area, and maximum depth were measured. Sediment samples from each location were studied and the flow velocity, stream power, Manning’s roughness coefficient, and shear stress were estimated. The results show that the bankfull channel cross-section area, width, width-to-depth ratio, and channel capacity increased between the beginning and middle of the river. Thereafter, the size of the river started to decrease in the lower alluvial area. This was characterized by gentle gradients, cohesive bank materials with grass cover, and channel switching. Within the lower part of the river, the channel capacity was observed to diminish as the drainage area increased. This increased the bankfull flow frequency and accelerated large floodwater losses in the floodplain via overbank flows and floodways.