Open AccessSEDIMENT DYNAMICS AND STABILITY STATUS OF THE KARRA KHOLA, HETAUDA DUN VALLEY, CENTRAL NEPAL SUB-HIMALAYA
Author(s) -
Naresh Kazi Tamrakar,
Suman Maharjan
Publication year - 2020
Publication title -
international journal of engineering technologies and management research
Language(s) - English
Resource type - Journals
ISSN - 2454-1907
DOI - 10.29121/ijetmr.v7.i11.2020.815
Subject(s) - aggradation , geology , stream power , hydrology (agriculture) , sediment , erosion , geomorphology , alluvium , sediment transport , shear stress , critical resolved shear stress , structural basin , geotechnical engineering , fluvial , shear rate , composite material , materials science , physics , quantum mechanics , viscosity
The Karra Khola in Hetauda, Siwalik region, originates within the Dun Valley, and contributes the Rapati Nadi in Hetauda Metropolitan city. The stability status of the river is of main concern because of rapid growing of the river corridor and peripheral land areas into suburban city. The river was surveyed for hydraulic parameters, sediment characteristics, and sediment loads. Rate of sediment transport and sediment yields were computed, and competency of the river was evaluated using Shield’s parameters and Reynolds numbers. The results show that the river sediments are sandy gravel to gravelly sands, and are moderately to very poorly sorted. The total sediment yield of the whole basin near the outlet is around 2% of the maximum total sediment yield. The specific stream power (SSP) ranges from 20.98 to 2866.34 Wm-2. The dimensionless boundary shear stress to dimensionless critical shear stress ratio exceeds unity, revealing that the river is competent enough to transport its bed material loads, except in downstream stretch before the river confluences with the Rapati Nadi. The Karra Khola clearly exhibits status of degradation in the upstream stretch, high rates of transportation due to lateral erosion in the midstream stretch, and aggradation in the downstream stretch.