Flow resistance in steep mountain streams

Abstract

Resistance to flow at low to moderate stream discharge was examined in five small (12-77 km 2 drainage area) tributaries of Chilliwack River, British Columbia, more than half of which exhibit planar bed morphology. The resulting data set is composed of eight to 12 individual estimates of the total resistance to flow at 61 cross sections located in 13 separate reaches of five tributaries to the main river. This new data set includes 625 individual estimates of resistance to flow at low to moderate river stage. Resistance to flow in these conditions is high, highly variable and strongly dependent on stage. The Darcy-Weisbach resistance factor (ff) varies over six orders of magnitude (0·29-12 700) and Manning's n varies over three orders of magnitude (0·047-7·95). Despite this extreme range, both power equations at the individual cross sections and Keulegan equations for reach-averaged values describe the hydraulic relations well. Roughness is divided into grain and form (considered as all non-grain sources) components. Form roughness is the dominant component, account-ing for about 90% of the total roughness of the system (i.e., form roughness is on average 8.6 times as great as grain roughness). Of the various quantitative and qualitative formroughness indicators observed, only the sorting coefficient (σ σ σ σ σ = = = = = D 84 /D 50 ) correlates well with form roughness.

Coarse Bed Sediments in a Headwater Channel as Indicators of Fluvial Processes and Slope-Channel Coupling: A Case Study from the Carpathian Mountains (Czech Republic)

“…Coarse bed sediments play an important role in highgradient streams as they act as important dissipaters of flow energy affecting the potential sediment transport and erosion processes (Reid, Hickin, 2008). Downstream coarsening of bed sediments was observed in headwater mountain watersheds (A < 10 km 2 ) with respect to continual sediment supply from adjacent hillslopes or scouring of debris-flows (Brummer, Montgomery, 2003;Wohl, Wilcox, 2005;Vianello, D'Agostino, 2007).…”

Controls on at‐a‐station hydraulic geometry in steep headwater streams, Colorado, USA

“…These objectives can be separated into two hypotheses: (i) there is a signifi cant difference between hydraulic geometry exponents for cascade versus step-pool reaches; and (ii) the variability in the hydraulic geometry exponents are signifi cantly related to the following potential control variables: bed gradient, channel roughness, wood load, and pool volume. The AHG for the single plane-bed reach is used for comparison with data collected from plane-bed reaches in British Columbia (Reid, 2005;Reid and Hickin, 2008). …”

Controls of channel morphology and sediment concentration on flow resistance in a large sand-bed river: A case study of the lower Yellow River

“…Investigations on flow resistance have survived for more than a century (Manning, 1891;Keulegan, 1938;Vanoni, 1941Vanoni, , 1946Vanoni and Brooks, 1957;Qian et al, 1959;Peterson and Mohanty, 1960;Simons and Richardson, 1960;Vanoni and Nomicos, 1960;Simons et al, 1963;Qian and Zhou, 1965;Rouse, 1965;Golubtsov, 1969;Limerinos, 1970;Judd and Peterson, 1969;Bathurst, 1978Bathurst, , 1985Bathurst, , 2002Bray, 1979;Hey, 1979;Davis and Sutherland, 1980;Griffiths, 1981;Jarret, 1984;Aguirre-Pe and Fuentes, 1990;Bennett, 1995;Dingman and Sharma, 1997;Nikora et al, 1998;Lee and Ferguson, 2002;Ferro, 2003;Ferguson, 2007Ferguson, , 2010López et al, 2007;Recking et al, 2008;Reid and Hickin, 2008;Comiti et al, 2009;David et al, 2010;Robert, 2011;Ferreira et al, 2012;Nitsche et al, 2012;Schneider et al, 2015). Among these studies, the methods used for quantifying flow resistance can be generally categorized into two major groups: (i) a characteristic particle size approach (or a semiempirical approach) …”

“…Among these studies, the methods used for quantifying flow resistance can be generally categorized into two major groups: (i) a characteristic particle size approach (or a semiempirical approach) (Keulegan, 1938;Vanoni and Brooks, 1957;Qian et al, 1959;Simons and Richardson, 1960;Vanoni and Nomicos, 1960;Simons et al, 1963;Rouse, 1965;Judd and Peterson, 1969;Bathurst, 1978Bathurst, , 1985Bathurst, , 2002Bray, 1979;Hey, 1979;Recking et al, 2008;Reid and Hickin, 2008), and (ii) a random field approach (or an empirical approach) (Jarret, 1984;Thorne and Zevenbergen, 1985;Rickenmann, 1994Rickenmann, , 1996Dingman and Sharma, 1997;Nikora et al, 1998;Comiti et al, 2007;Aberle and Smart, 2003;Aberle et al, 2010).…”