Dominant discharges for suspended sediment transport in a highly active Pyrenean river

PurposeDominant discharges and associated sediment dynamics of the River Isábena, a 445-km2 catchment in the central Pyrenees of Spain that is punctuated by badlands, are analysed.Materials and methodsCalculations of suspended sediment loads are based on continuous records of discharge and turbidity obtained at the basin outlet for the period 2005–2010.Results and discussionDominant discharges for sediment load (i.e. effective discharge) present a bimodal distribution, with one peak falling in the range of low flows and the other associated to less frequent but higher magnitude floods (i.e. bankfull). The highly suspended sediment availability in the badlands, together with the high connectivity between the badlands and the stream network and the important in-channel fine sediment storage, causes both large and small events to remobilize fines. Baseflows, despite their low competence, generate resuspension and massive sediment loads. Thus, effective discharge (i.e. the discharge which transports most of the sediment) is not solely associated with bankfull (i.e. the discharge that dominates channel form), but to a wider range of discharges. Consequently, this river channel is not specifically adjusted to convey most of the sediment load during high floods, as in many other rivers, but instead large volumes of sediment are transferred downstream at an almost constant rate.ConclusionsResults suggest that dominant discharge may play a lesser role in terms of (suspended) sediment load in non-supply-limited fluvial systems and/or in rivers that permanently work close to, or at, full transport capacity, as is the case of the Isábena.

[1]  T. Anderson.  View from the river. , 2007, The practising midwife.

[2]  Kenneth Gregory,et al.  River channel changes , 1977 .

[3]  A. Quader,et al.  Analytical estimation of effective discharge for small southern Ontario streams , 2008 .

[4]  J. Stedinger,et al.  Discharge indices for water quality loads , 2003 .

[5]  D. Vericat,et al.  Suspended sediment dynamics in a large regulated river over a 10-year period (the lower Ebro, NE Iberian Peninsula) , 2011 .

[6]  Brian P. Bledsoe,et al.  GeoTools: A Toolkit for Fluvial System Analysis 1 , 2007 .

[7]  F. Alonso-Sarría,et al.  Erosion rates obtained from check-dam sedimentation (SE Spain). A multi-method comparison , 2007 .

[8]  W. Stephenson,et al.  Two‐hourly surface change on supra‐tidal rock (Marengo, Victoria, Australia) , 2007 .

[9]  V. Yevjevich.  Probability and statistics in hydrology , 1972 .

[10]  M. Wolman,et al.  Magnitude and Frequency of Forces in Geomorphic Processes , 1960, The Journal of Geology.

[11]  M. Kent,et al.  Channel change, bankfull and effective discharges on a vertically accreting, meandering, gravel‐bed river , 2007 .

[12]  Jiongxin Xu,et al.  Variability of effective discharge for suspended sediment transport in a large semi-arid river basin , 2010 .

[13]  F. Comiti,et al.  Effective discharge for sediment transport in a mountain river: Computational approaches and geomorphic effectiveness , 2006 .

[14]  Damià Vericat,et al.  Rainfall, runoff and sediment transport relations in a mesoscale mountainous catchment: The River Isábena (Ebro basin) , 2010 .

[15]  D. Walling,et al.  The magnitude and frequency characteristics of fluvial transport in a devon drainage basin and some geomorphological implications , 1982 .

[16]  D. Nash.  Effective Sediment-Transporting Discharge from Magnitude-Frequency Analysis , 1994, The Journal of Geology.

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

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

[19]  Thomas E. Lisle,et al.  Bankfull discharge and sediment transport in northwestern California , 1987 .

[20]  V. Ferro,et al.  Identifying a dominant discharge for natural rivers in southern Italy , 2012 .

[21]  Anton Van Rompaey,et al.  Predicting catchment sediment yield in Mediterranean environments: the importance of sediment sources and connectivity in Italian drainage basins , 2006 .

[22]  A. Simon,et al.  Suspended-sediment transport rates at the 1.5-year recurrence interval for ecoregions of the United States: transport conditions at the bankfull and effective discharge? , 2004 .

[23]  H. Knapp,et al.  Effective discharge recurrence intervals of Illinois streams , 2005 .

[24]  P. Hoel.  Elementary Statistics: 4th Ed , 1976 .

[25]  M. Wolman.  The natural channel of Brandywine Creek, Pennsylvania , 1955 .

[26]  R. Vogel,et al.  Effective Measures of “Effective” Discharge , 2011, The Journal of Geology.

[27]  Axel Bronstert,et al.  Flood‐based analysis of high‐magnitude sediment transport using a non‐parametric method , 2008 .

[28]  W. Hays.  Statistics, 4th ed. , 1988 .

[29]  Damià Vericat,et al.  Suspended sediment transport in a highly erodible catchment: the River Isábena (Southern Pyrenees). , 2009 .

[30]  P. Jackson,et al.  BANKFULL DISCHARGE RECURRENCE INTERVALS AND REGIONAL HYDRAULIC GEOMETRY RELATIONSHIPS: PATTERNS IN THE PACIFIC NORTHWEST, USA 1 , 2001 .

[31]  L. B. Leopold,et al.  Water In Environmental Planning , 1978 .

[32]  R. Daniel,et al.  Bankfull hydraulic geometry relationships for North Carolina streams , 1999 .

[33]  D. Walling,et al.  The role of channel and floodplain storage in the suspended sediment budget of the River Ouse, Yorkshire, UK , 1998 .

[34]  J. López-Tarazón,et al.  In-channel sediment storage in a highly erodible catchment: the River Isábena (Ebro Basin, Southern Pyrenees) , 2011 .

[35]  J. de Vente,et al.  The impact of land use change and check‐dams on catchment sediment yield , 2008 .

[36]  Damià Vericat,et al.  The sediment budget of a highly dynamic mesoscale catchment: The River Isábena , 2012 .

[37]  P. Porto,et al.  ULTIMATE BED SLOPE IN CALABRIAN STREAMS UPSTREAM OF CHECK DAMS: FIELD STUDY , 1999 .

[38]  Predicting the equilibrium bed slope in natural streams using a stochastic model for incipient sediment motion , 2011 .

[39]  G. Pickup,et al.  ADJUSTMENT OF STREAM-CHANNEL SHAPE TO HYDROLOGIC REGIME , 1976 .

[40]  E. Andrews.  Effective and bankfull discharges of streams in the Yampa River basin, Colorado and Wyoming , 1980 .

[41]  A. S. Brodilov.  Critical values of hydraulic elements of the dominant discharge of the Yenisei River in the lower pool of the Sayano-Shushenskoe hydroelectric station , 1996 .

[42]  S. Schumm.  The shape of alluvial channels in relation to sediment type , 1960 .

[43]  R. Vogel,et al.  Effective Measures of ''Effective Discharge'' , 2008 .

[44]  F. D. Shields,et al.  Design for Stream Restoration , 2003 .

[45]  L. B. Leopold,et al.  River flood plains: Some observations on their formation , 1957 .

[46]  J. Phillips.  Geomorphic impacts of flash flooding in a forested headwater basin , 2002 .

[47]  P. J. Whiting,et al.  Sediment-transporting flows in headwater streams , 1999 .

[48]  R. Batalla,et al.  Chapter 8 A decade of sediment transport measurements in a large Mediterranean river (the Tordera, Catalan Ranges, NE Spain) , 2005 .

[49]  P. Ashmore,et al.  Effective discharge for suspended sediment transport in streams of the Saskatchewan River Basin , 1988 .

[50]  D. Vericat,et al.  Sediment transport from continuous monitoring in a perennial Mediterranean stream , 2010 .

[51]  D. Thomas,et al.  A DEFINITION OF DOMINANT DISCHARGE , 1966 .

[52]  D. Vericat,et al.  Reach and catchment-scale influences on invertebrate assemblages in a river with naturally high fine sediment loads , 2013 .

[53]  J. Smith,et al.  Calculations of the critical shear stress for motion of uniform and heterogeneous sediments , 1987 .

[54]  H. Sichingabula.  Magnitude‐frequency characteristics of effective discharge for suspended sediment transport, Fraser River, British Columbia, Canada , 1999 .