Hydraulic Parameters and Morphometric Variables Interactions in Bedrock Channel

Abstract

Biswas B., das B. C., 2016. Hydraulic parameters and morphometric variables interactions in bedrock channel. Quaestiones Geographicae 35(3), Bogucki Wydawnictwo Naukowe, Poznań, pp. 75-88, 12 figs.aBstraCt: Present study is on the interdependent nature of hydraulic parameters and morphometric variables of a bedrock river. In this study, using dumpy level, GPS, satellite images and some mathematical equations a data set on hydraulics and morphometric variables of a bedrock channel, named Bhatajhor, of eastern India was generated. That data set was used to (1) find out impulse-response relations between hydraulic variables (2) find out relations between morphometric variables and (3) find out relations between hydraulic and morphometric variables. Seven equations (5-11) were formulated based on this empirical study to the end. The seven empirical relations, most of which include only two variables, involve channel cross-section dimensions (area, width, mean depth, maximum depth, width/ depth ratio, hydraulic radius), slope and hydraulic variables (velocity, kinetic energy, stream power, Manning's n factor, Chezy's C factor and shear stress). Observation shows relatively higher coefficient of determination (R2) between variables like velocity and Manning's n factor (0.67), velocity and Chezy's C factor (0.67), slope and τ (0.89), w/d ratio and hydraulic radius (0.53), slope and w/d ratio (0.50).

Flow structure in large bedrock‐channels: The example of macroturbulent rapids, lower Mekong River, Southeast Asia

“…These values of bed roughness are consistent with modelled roughness values calculated for low flows within bedrock reaches of the Mekong at Siphandone, downstream of the present study reaches (Van et al, 2012;their Figure 12) as well as for high Reynolds number flows (10 5 < Re < 10 7 ) within small bedrock channels devoid of bed sediment (Richardson and Carling, 2006;Ferguson et al, 2017). Other published Chezy-C data are indirect estimates for shallow flows in small bedrock streams (Biswas and Das, 2016) and so are not directly comparable.…”

“…Moreover, in the following text we use the term 'bulk flow' as a term related to the general movement of mass flow due to pressure gradients and, in particular, the derivations of flow parameters that most commonly are averaged across sections and/or in the vertical. Rather, most data pertain to relatively small shallow streams and consist of limited parameter estimates for peak flows (examples reported in Baker and Costa, 1987;Siddiqui and Robert, 2010;Mitchell et al, 2013), bulk-flow estimations using dye-dilution (Richardson and Carling, 2005), bulk flow parameter estimates derived using hydraulic geometry (Barbour et al, 2009;Biswas and Das, 2016;Ferguson et al, 2017), or hydraulic modelling estimates of flow fields (Brown and Pasternack, 2014). Only one detailed and significant interpretation of the velocity flow structure across the centreline of deep canyons along the Fraser River has been presented by Venditti et al (2014) and supported by laboratory experiments (Hunt et al, 2018).…”

“…Only one detailed and significant interpretation of the velocity flow structure across the centreline of deep canyons along the Fraser River has been presented by Venditti et al (2014) and supported by laboratory experiments (Hunt et al, 2018). Rather, most data pertain to relatively small shallow streams and consist of limited parameter estimates for peak flows (examples reported in Baker and Costa, 1987;Siddiqui and Robert, 2010;Mitchell et al, 2013), bulk-flow estimations using dye-dilution (Richardson and Carling, 2005), bulk flow parameter estimates derived using hydraulic geometry (Barbour et al, 2009;Biswas and Das, 2016;Ferguson et al, 2017), or hydraulic modelling estimates of flow fields (Brown and Pasternack, 2014).…”

A critical review of environmental factors influencing the transport dynamics of microplastics in riverine systems: implications for ecological studies

“…Bed shear stress is a force per unit area of the bed (in N m −2 ) and increases with flow depth and steepness of the channel (Biswas and Chandra Das 2016). The coarse particles lying on riverbeds are set into motion during floods when critical shear stress is passed (Bravard and Petit 2009).…”

“…Furthermore, the hydraulic attributes (flow-related abiotic factors, e.g. substrate type, depth, flow velocity) in each hydraulic biotope (Wadeson and Rowntree 1998;Biswas and Chandra Das 2016) impact on the deposition, suspension, and remobilisation of MPs (Kumar et al 2021;Newbould et al 2021). For example, dimensionless hydraulic indices developed through the integration of depth, velocity, and bed roughness can provide insight into the prevailing hydrodynamic conditions in each distinct biotope (Jowett and Richardson 1990;Jowett et al 1991;Wadeson 1994;Wadeson and Rowntree 1998), which in turn, can inform our understanding of how hydraulic biotopes may influence the behaviour of MPs and the instream factors impacting their concentrations in different morphological units and landforms in river systems.…”