Hydraulic Geometry and Resistance of Gravel-Bed Rivers

The Gravel-Bed River Reach Properties Estimation in Bank Slope Modelling

“…In the analysis of river and channel problems it must be given a relationship between the average velocity U, the depth h or the hydraulic radius R, channel slope S and some coefficient which is related to the channel boundary. This is known as the resistance relationship [3]. The work of Lacey [4] about the sand-bed rivers has shown that for such rivers depth h or hydraulic radius R ~ (Q/f 1 ) 1/3 , width W or wetted perimeter PQ 0.50 , Area A ~ Q 5/6 / f 1 1/3 where f 1 is Lacey's silt factor and is given by f 1 = 1,76 (d) 0.5 , d being the median size of bed material in mm.…”

“…The work of Lacey [4] about the sand-bed rivers has shown that for such rivers depth h or hydraulic radius R ~ (Q/f 1 ) 1/3 , width W or wetted perimeter PQ 0.50 , Area A ~ Q 5/6 / f 1 1/3 where f 1 is Lacey's silt factor and is given by f 1 = 1,76 (d) 0.5 , d being the median size of bed material in mm. As regards the gravel-bed rivers Kellerhals and Bray [5] have related W, h, A to Q and sediment size d as [3]. Hence Δγ s is the difference in specific weights of sediment and water and ρ f is the mass density of water.…”

“…In the analysis of river and channelproblems we need also a relationship between the average velocity U, the depth h or the hydraulic radius R, channel slope S and some coefficient which is related to the channelboundary. This is known as the resistance relationship [3]. The resistance relationship isexpressed in dimensionless form as [3],…”

“…This is known as the resistance relationship [3]. The resistance relationship isexpressed in dimensionless form as [3],…”

“…In the above equations n is Manning's roughness coefficient, C is Chezy's discharge coefficient, f is Darcy-Weisbach resistance coefficient and F is a function. These coefficientsdepend on the resistance, offered to the flow by the channel boundary and air-water interface [3]. The available data in Turkey at East Black Sea Basin have been analysed in a unified manner to obtain dimensionally homogeneous relationships for W, h, A and U.…”