Hyporheic exchange due to channel‐spanning logs

[1] The flow of river water around large woody debris (LWD) creates pressure gradients along the riverbed that drive a large zone of river-groundwater mixing, or hyporheic exchange. Flume experiments and numerical simulations show that river water downwells into the riverbed upstream of a channel-spanning log and upwells downstream. Exchange rates are greatest near the log and decay exponentially with distance upstream and downstream. We developed equations for bed pressure profiles and hyporheic exchange rates in the vicinity of a channel-spanning log that can be used to evaluate the impact of LWD removal or reintroduction on hyporheic mixing. The magnitude of pressure disturbance along the bed (and thus hyporheic exchange) increases with the fraction of channel depth blocked by the log and channel Froude number. Exchange rates are relatively insensitive to relative depth of the log (gap ratio). At natural densities, LWD in lowland streams drives reach-averaged hyporheic exchange rates similar to a ripple-covered bed. However, the length scales and residence times of hyporheic exchange due to LWD are greater. By removing LWD from streams, humans have altered patterns and rates of hyporheic exchange, which influence habitat distribution and quality for invertebrates and fish.

[1]  Theodore A. Endreny,et al.  Hyporheic flow path response to hydraulic jumps at river steps: Flume and hydrodynamic models , 2011 .

[2]  Michael Manga,et al.  Stress partitioning in streams by large woody debris , 2000 .

[3]  R. Fanelli,et al.  Seasonal biogeochemical hotspots in the streambed around restoration structures , 2008 .

[4]  J. Bear.  Dynamics of Fluids in Porous Media , 1975 .

[5]  E. Wohl,et al.  Neighborhood matters: Patterns and controls on wood distribution in old-growth forest streams of the Colorado Front Range, USA , 2011 .

[6]  J. Stanford,et al.  The hyporheic habitat of river ecosystems , 1988, Nature.

[7]  L. Ridolfi,et al.  Gravity‐driven water exchange between streams and hyporheic zones , 2009 .

[8]  E. Wohl,et al.  Flow resistance dynamics in step‐pool stream channels: 1. Large woody debris and controls on total resistance , 2006 .

[9]  M. Brunke,et al.  The ecological significance of exchange processes between rivers and groundwater , 1997 .

[10]  J. Webster,et al.  Influence of log additions on physical and biotic characteristics of a mountain stream , 1995 .

[11]  L. Lautz,et al.  Impact of debris dams on hyporheic interaction along a semi‐arid stream , 2006 .

[12]  G. Poole,et al.  An Ecological Perspective on In-Stream Temperature: Natural Heat Dynamics and Mechanisms of Human-CausedThermal Degradation , 2001, Environmental management.

[13]  J. Meyer,et al.  Effects of litter exclusion and wood removal on phosphorus and nitrogen retention in a forest stream , 2000 .

[14]  F. Swanson,et al.  Large wood and fluvial processes , 2002 .

[15]  Hervé Piégay,et al.  Wood in rivers: interactions with channel morphology and processes , 2003 .

[16]  C. Thorne,et al.  Influence of large woody debris on morphological evolution of incised, sand-bed channels , 2004 .

[17]  Christopher J. Gippel,et al.  Environmental Hydraulics of Large Woody Debris in Streams and Rivers , 1995 .

[18]  James R. Karr,et al.  Relationships between Woody Debris and Fish Habitat in a Small Warmwater Stream , 1984 .

[19]  B. Finlayson,et al.  Hydraulic guidelines for the re-introduction and management of large woody debris in lowland rivers , 1996 .

[20]  Dongfang Liang,et al.  Numerical modeling of flow and scour below a pipeline in currents: Part II. Scour simulation , 2005 .

[21]  M. M. Zdravkovich,et al.  Flow around a circular cylinder near a plane boundary , 1978, Journal of Fluid Mechanics.

[22]  B. O’Connor,et al.  Scaling hyporheic exchange and its influence on biogeochemical reactions in aquatic ecosystems , 2008 .

[23]  Roy Haggerty,et al.  Changes in hyporheic exchange flow following experimental wood removal in a small, low‐gradient stream , 2009 .

[24]  Effects of multiscale anisotropy on basin and hyporheic groundwater flow. , 2011, Ground water.

[25]  Alan R. Hill,et al.  Effects of riffle-step restoration on hyporheic zone chemistry in N-rich lowland streams , 2006 .

[26]  D. Montgomery,et al.  Distribution of bedrock and alluvial channels in forested mountain drainage basins , 1996, Nature.

[27]  Martin W. Doyle,et al.  In‐stream geomorphic structures as drivers of hyporheic exchange , 2008 .

[28]  D. Montgomery,et al.  LARGE WOODY DEBRIS JAMS, CHANNEL HYDRAULICS AND HABITAT FORMATION IN LARGE RIVERS , 1996 .

[29]  D. Hering,et al.  Coarse Woody Debris Quantity and Distribution in Central European Streams , 2000 .

[30]  Gordon E. Grant,et al.  When do logs move in rivers? , 2000 .

[31]  C. W. Hirt,et al.  Volume of fluid (VOF) method for the dynamics of free boundaries , 1981 .

[32]  M. Doyle,et al.  The influence of in‐stream structures on summer water temperatures via induced hyporheic exchange , 2009 .

[33]  M. Doyle,et al.  In‐channel transient storage and associated nutrient retention: Evidence from experimental manipulations , 2005 .

[34]  G. Likens,et al.  IMPORTANCE OF ORGANIC DEBRIS DAMS IN THE STRUCTURE AND FUNCTION OF STREAM ECOSYSTEMS , 1980 .

[35]  L. Lautz,et al.  Hyporheic flow path response to hydraulic jumps at river steps: Hydrostatic model simulations , 2011 .

[36]  A. Packman,et al.  Stream-subsurface exchange of zinc in the presence of silica and kaolinite colloids. , 2004, Environmental science & technology.

[37]  Andrew J. Boulton,et al.  Hyporheic rehabilitation in rivers: restoring vertical connectivity , 2007 .

[38]  Roy Haggerty,et al.  Residence time of bedform-driven hyporheic exchange , 2008 .

[39]  K. G. Ranga Raju,et al.  RATIONAL ASSESSMENT OF BLOCKAGE EFFECT IN CHANNEL FLOW PAST SMOOTH CIRCULAR CYLINDERS , 1983 .

[40]  D. Montgomery,et al.  Patterns and processes of wood debris accumulation in the Queets river basin, Washington , 2003 .

[41]  R. Bilby.  Role of Organic Debris Dams in Regulating the Export of Dissolved and Particulate Matter from a Forested Watershed , 1981 .

[42]  Sean J. Bennett,et al.  Surface Wave Forces Acting on Submerged Logs , 2002 .

[43]  F. D. Shields,et al.  Large wood addition for aquatic habitat rehabilitation in an incised, sand‐bed stream, Little Topashaw Creek, Mississippi , 2006 .

[44]  D. Lerner,et al.  Pollutant attenuation at the groundwater-surface water interface: a classification scheme and statistical analysis using national-scale nitrate data. , 2009 .

[45]  M. Bayani Cardenas,et al.  Dunes, turbulent eddies, and interfacial exchange with permeable sediments , 2007 .

[46]  A. Flecker,et al.  Deforesting the riverscape: the effects of wood on fish diversity in a Venezuelan piedmont stream , 2004 .

[47]  M. Mutz,et al.  Effect of instream wood on vertical water flux in low‐energy sand bed flume experiments , 2007 .

[48]  F. Douglas Shields,et al.  PREDICTION OF EFFECTS OF WOODY DEBRIS REMOVAL ON FLOW RESISTANCE , 1995 .

[49]  Michael Manga,et al.  Field measurements of drag coefficients for model large woody debris , 2003 .

[50]  M. Pusch,et al.  A River's Liver – Microbial Processes within the Hyporheic Zone of a Large Lowland River , 2005 .

[51]  E. Hester,et al.  Moving beyond the banks: hyporheic restoration is fundamental to restoring ecological services and functions of streams. , 2010, Environmental science & technology.

[52]  E. Wohl,et al.  Flow resistance dynamics in step‐pool channels: 2. Partitioning between grain, spill, and woody debris resistance , 2006 .