Downstream hydraulic geometry of rivers in Victoria, Australia

Abstract Downstream variation of hydraulic geometry in rivers, characterized by fine textured banks and low width to depth ratios (7–25), is investigated in Victoria, Australia, with the aim of developing predictive models of channel geometry for large-scale spatial modeling applications. A one-dimensional hydraulic model is used to determine the mean bank-full geometry and discharge ( Q bf ) for 93 sites which are investigated in relation to discharge of fixed average recurrence interval (ARI). The median bank-full ARI is estimated at 0.8 years with 75% of sites between 0.5 and 2.5 years. Exponents in the downstream hydraulic geometry relations for width, depth and velocity are respectively 0.43, 0.40 and 0.18 ( Q  =  Q bf ) and 0.44, 0.38 and 0.03 ( Q  =  Q 2 , i.e., 2-year ARI), falling near the mode of global values. Q 2 and slope explain 66% of variance in Q bf , while Q 2 explains 73% and 69% of the variance in width and depth relations, respectively: Q 2 provides a reliable substitute for Q bf in spatial modeling applications. Spatial variation in hydraulic geometry relations within and between river basins remains largely unexplained. The W / D ratio characteristically decreases with increasing distance along the lower reaches of most rivers and this has contributed to the lower than expected value for the width exponent.

[1]  Jon Brodie,et al.  Sources of sediment to the Great Barrier Reef World Heritage Area. , 2005, Marine pollution bulletin.

[2]  R. Warner,et al.  The multivariate controls of hydraulic geometry: A causal investigation in terms of boundary shear distribution , 1995 .

[3]  Jonathan D. Phillips,et al.  The instability of hydraulic geometry , 1990 .

[4]  T. McMahon,et al.  A method for characterising longitudinal irregularity in river channels , 1997 .

[5]  Keith Richards,et al.  Rivers: Form and Process in Alluvial Channels , 1982 .

[6]  Scott N. Wilkinson,et al.  Regionalizing mean annual flow and daily flow variability for basin‐scale sediment and nutrient modelling , 2006 .

[7]  W. J. Young,et al.  Large-scale patterns of erosion and sediment transport in river networks, with examples from Australia , 2001 .

[8]  F. D. Shields,et al.  Incorporation of Environmental Features in Flood Control Channel Projects. , 1985 .

[9]  L. Lymburner,et al.  Regional Patterns of Riparian Vegetation, Erosion and Sediment Transport in the Ovens River Basin , 2005 .

[10]  D. Knighton.  Fluvial Forms and Processes: A New Perspective , 1998 .

[11]  C. Thorne,et al.  Stable Channels with Mobile Gravel Beds , 1986 .

[12]  S. Maynord.  Wave height from planing and semi‐planing small boats , 2005 .

[13]  K. Page,et al.  Stratigraphic architecture resulting from Late Quaternary evolution of the Riverine Plain, south‐eastern Australia , 1996 .

[14]  Howard H. Chang.  Fluvial Processes in River Engineering , 1988 .

[15]  Brian P. Bledsoe,et al.  WIDTH OF STREAMS AND RIVERS IN RESPONSE TO VEGETATION, BANK MATERIAL, AND OTHER FACTORS 1 , 2004 .

[16]  I. DeRose.  Regional Models of Stream Channel Metrics Bibliography , 2005 .

[17]  R. Derose,et al.  Variability and uncertainty in reach bankfull hydraulic geometry , 2008 .

[18]  M. Wolman.  A method of sampling coarse river‐bed material , 1954 .

[19]  B. Eaton,et al.  Predicting downstream hydraulic geometry: A test of rational regime theory , 2007 .

[20]  I. Rutherfurd,et al.  History and Effects of Channelisation on the Latrobe River, Victoria , 1995 .

[21]  G. Brierley,et al.  The long-term control of vegetation and woody debris on channel and flood-plain evolution: insights from a paired catchment study in southeastern Australia , 2003 .

[22]  S. V. Chitale.  Theories and relationships of river channel patterns , 1973 .

[23]  Richard D. Hey,et al.  Gravel-Bed Rivers: Fluvial Processes, Engineering and Management , 1982 .

[24]  M. Gordon Wolman,et al.  Fluvial Processes in Geomorphology , 1965 .

[25]  Nick J. Mount,et al.  The effect of altered flow regime on the frequency and duration of bankfull discharge: Murrumbidgee River, Australia , 2005 .

[26]  F. Kolberg,et al.  Active Channel Geometry and Discharge Relations of U.S. Piedmont and Midwestern Streams: The Variable Exponent Model Revisited , 1995 .

[27]  F. Henderson.  Open channel flow , 1966 .

[28]  G. Dury.  Magnitude-frequency analysis and channel morphometry , 1973 .

[29]  Vijay P. Singh,et al.  Downstream hydraulic geometry relations: 1. Theoretical development , 2003 .

[30]  Simon Lang,et al.  A review of empirical equations for estimating stream roughness and their application to four streams in Victoria , 2004 .

[31]  I. Jowett.  Hydraulic geometry of New Zealand rivers and its use as a preliminary method of habitat assessment , 1998 .

[32]  S. Schumm.  The Fluvial System , 1977 .

[33]  E. Andrews.  Bed-material entrainment and hydraulic geometry of gravel-bed rivers in Colorado , 1984 .

[34]  Chris C. Park.  World-wide variations in hydraulic geometry exponents of stream channels: An analysis and some observations , 1977 .

[35]  L. B. Leopold,et al.  The hydraulic geometry of stream channels and some physiographic implications , 1953 .

[36]  B. Rhoads.  A Continuously Varying Parameter Model of Downstream Hydraulic Geometry , 1991 .

[37]  Ian P. Prosser,et al.  Investment prioritization based on broadscale spatial budgeting to meet downstream targets for suspended sediment loads , 2004 .

[38]  K. Page,et al.  Channel Adjustment Following the Crossing of a Threshold: Tarcutta Creek, Southeastern Australia , 1998 .

[39]  G. Pickup,et al.  Effects of hydrologic regime on magnitude and frequency of dominant discharge , 1976 .

[40]  G. Williams.  Bank‐full discharge of rivers , 1978 .

[41]  S. Lawrence Dingman,et al.  Statistical development and validation of discharge equations for natural channels , 1997 .

[42]  G. Nanson,et al.  Vegetation and channel variation; a case study of four small streams in southeastern Australia , 1997 .

[43]  G. Williams.  River meanders and channel size , 1986 .

[44]  Donald Robert Coates,et al.  Thresholds in Geomorphology , 2020 .

[45]  M. Stewardson.  Hydraulic geometry of stream reaches , 2005 .

[46]  W. Erskine,et al.  Morphology, hydrology, and evolution of the anastomosing Ovens and King Rivers, Victoria, Australia , 1996 .

[47]  G. Nanson,et al.  Downstream reduction of rural channel size with contrasting urban effects in small coastal streams of southeastern Australia , 1981 .

[48]  E. Foufoula‐Georgiou,et al.  Fluvial processes and streamflow variability: Interplay in the scale‐frequency continuum and implications for scaling , 2005 .

[49]  G. Nanson,et al.  The influence of bank strength on channel geometry: an integrated analysis of some observations , 1998 .

[50]  George A. Griffiths,et al.  Stable-channel design in gravel-bed rivers , 1981 .