Papers by Mahendra Baniya
38th IAHR World Congress - "Water: Connecting the World", 2019
Riparian vegetation depicts the condition of river channels. Midstream channel of continental riv... more Riparian vegetation depicts the condition of river channels. Midstream channel of continental rivers is covered with tall old trees until shoreline of water, while riparian zone is covered with gravelly substrate in the midstream of the steep rivers. The difference in vegetation is caused by the difference in the sediment supply into the river channel and the sediment deposition along the river channel, which inhibits the recovery of vegetation afterwards. In this study, a dynamic riparian vegetation model (DRIPVEM), capable of evaluating the growth of riparian trees, was used to evaluate the stable condition of vegetation coverage under the condition of flood hydrology and sediment yield in to the river channel. The gravelly rivers produced vegetation coverage after 50 years, which is highly influenced by the deposition area fraction, particularly dependent on the flood level. In sandy rivers, on the other hand, flood intensity affects the vegetation coverage rather than the deposition area fraction. The low nitrogen concentration of the deposited sediment which is a detrimental factor of vegetation coverage, decreases with the nitrogen concentration of the deposited sediment in gravelly channels, as gravel deposition suppresses the re-colonization of vegetation; however, for sandy channels, vegetation coverage increases with increasing deposition area fraction as the higher nitrogen concentration accelerates the vegetation recovery. This indicates that channels having mild slopes with sandy sediments, the vegetation recovery is not suppressed after a flood, and thickly forestated until shoreline. In the steep channels with gravel sediment sources nearby, gravel deposition at flood time, suppress the recovery of vegetation.
Water, 2020
Light is an important factor that affects cyanobacterial growth and changes in light can influenc... more Light is an important factor that affects cyanobacterial growth and changes in light can influence their growth and physiology. However, an information gap exists regarding light-induced oxidative stress and the species-specific behavior of cyanobacteria under various light levels. This study was conducted to evaluate the comparative effects of different light intensities on the growth and stress responses of two cyanobacteria species, Pseudanabaena galeata (strain NIES 512) and Microcystis aeruginosa (strain NIES 111), after periods of two and eight days. The cyanobacterial cultures were grown under the following different light intensities: 0, 10, 30, 50, 100, 300, and 600 μmol m−2 s−1. The optical density (OD730), chlorophyll a (Chl-a) content, protein content, H2O2 content, and the antioxidative enzyme activities of catalase (CAT) and peroxidase (POD) were measured separately in each cyanobacteria species. P. galeata was negatively affected by light intensities lower than 30 μmo...
Water, 2019
The ecological dynamics of riparian areas interact with sediment transport in river systems, whic... more The ecological dynamics of riparian areas interact with sediment transport in river systems, which plays an active role in riparian vegetation growth in the floodplain. The fluvial dynamics, hydraulics, hydro-meteorological and geomorphological characteristics of rivers are associated with sediment transport in river systems and around the riparian area. The flood disturbance, sediment with nutrients and seeds transported by river, sediment deposition, and erosion phenomena in the floodplain change the bare land area to vegetation area and vice versa. The difference in riparian vegetation area in the river floodplain is dependent on the sediment grain size distribution which is deposited in the river floodplain. Mathematical models describing vegetation growth in a short period exist in literature, but long-term modelling and validations are still lacking. In order to cover long-term vegetation growth modelling, a Dynamic Riparian Vegetation Model (DRIPVEM) was proposed. This paper ...
Water, 2019
Sediment yield is a complex phenomenon of weathering, land sliding, and glacial and fluvial erosi... more Sediment yield is a complex phenomenon of weathering, land sliding, and glacial and fluvial erosion. It is highly dependent on the catchment area, topography, slope of the catchment terrain, rainfall, temperature, and soil characteristics. This study was designed to evaluate the key hydraulic parameters of sediment transport for Kali Gandaki River at Setibeni, Syangja, located about 5 km upstream from a hydropower dam. Key parameters, including the bed shear stress (τb), specific stream power (ω), and flow velocity (v) associated with the maximum boulder size transport, were determined throughout the years, 2003 to 2011, by using a derived lower boundary equation. Clockwise hysteresis loops of the average hysteresis index of +1.59 were developed and an average of 40.904 ± 12.453 Megatons (Mt) suspended sediment have been transported annually from the higher Himalayas to the hydropower reservoir. Artificial neural networks (ANNs) were used to predict the daily suspended sediment rate...
International Journal of River Basin Management, 2011
Growth patterns of Phragmites japonica associated with soil characteristics were observed at the ... more Growth patterns of Phragmites japonica associated with soil characteristics were observed at the sediment bar of the Arakawa River, Japan. Accumulating fine sediments on the bar altered the habitat condition and made it accessible for the growth of P. japonica. The total biomass of the P. japonica shoots was higher in the fine sediments probably due to the better availability
Theoretical and Applied Climatology
Journal of Water and Environment Technology
The construction of dams across rivers controls the magnitude of downstream floods and limits the... more The construction of dams across rivers controls the magnitude of downstream floods and limits the suspended sediment transport into the downstream areas. We elucidated the downstream hydrological alterations compared to upstream after the construction of Kali Gandaki 'A' hydropower dam, Syangja, Nepal using continuous wavelet analysis, cross wavelet analysis and wavelet coherence. The downstream fluvial flow in winter and pre-monsoon seasons showed highest water deficit condition compared to monsoon and post-monsoon seasons. The dam-induced changes in fluvial flow with decreasing amount of sediment alter the downstream flood morphological characteristics of river reach such as flood depth, wetted perimeter of river section, flow velocity, and maximum and minimum floods together with the decrease in amount of suspended sediment. The dam-induced downstream alterations directly or indirectly create stress on the aquatic as well as terrestrial ecosystems. The findings of this study will be useful for hydropower dam gates operation that fulfils the minimum ecological threshold.
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Papers by Mahendra Baniya