Treating causes not symptoms: restoration of surface―groundwater interactions in rivers

Many river restoration projects seek to address issues associated with impaired hydrological and ecological connectivity in longitudinal (e.g. effects of dams, weirs) or lateral (e.g. alienated floodplain) dimensions. Efforts to restore the vertical dimension of impaired stream–groundwater exchange are rare, hampered by limited understanding of the factors controlling this linkage in natural alluvial rivers. We propose a simplified two-axis model of the ‘primary drivers’ (sediment structure and vertical hydraulic gradient) of stream–groundwater exchange that acknowledges their interaction and provides a practical template to help researchers and river managers pose hypothesis-driven solutions to restoration of damaged or lost vertical connectivity. Many human activities impact on one or both of these drivers, and we review some of the tools available for treating the causes (rather than symptoms) in impacted stream reaches. For example, creating riffle-pool sequences along stream reaches will enhance vertical hydraulic gradient, whereas flushing flows can remove clogging layers and sustain sediment permeability. Our model is a first step to specifying mechanisms for recovery of lost vertical connectivity. Assessing results of river restoration using this approach at reach to catchment scales will provide scientific insights into the interplay of hydrology, fluvial geomorphology and river ecosystem function at appropriately broad scales.

[1]  Brian D. Collins,et al.  Geomorphic effects of wood in rivers , 2003 .

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

[3]  P. Marmonier,et al.  Effects of bottom sediment restoration on interstitial habitat characteristics and benthic macroinvertebrate assemblages in a headwater stream , 2007 .

[4]  Emily H. Stanley,et al.  THE FUNCTIONAL SIGNIFICANCE OF THE HYPORHEIC ZONE IN STREAMS AND RIVERS , 1998 .

[5]  D. Hicks,et al.  The Selwyn River of New Zealand: a benchmark system for alluvial plain rivers , 2008 .

[6]  John A. Cherry,et al.  A Field Exercise on Groundwater Flow Using Seepage Meters and Mini-piezometers , 1979 .

[7]  J. Meyer,et al.  Standards for ecologically successful river restoration , 2005 .

[8]  D. McKnight,et al.  Weathering reactions and hyporheic exchange controls on stream water chemistry in a glacial meltwater stream in the McMurdo Dry Valleys , 2002 .

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

[10]  Michael E. Campana,et al.  Seasonal variation in surface‐subsurface water exchange and lateral hyporheic area of two stream‐aquifer systems , 1998 .

[11]  M. Harvey,et al.  Biodiversity, functional roles and ecosystem services of groundwater invertebrates , 2008 .

[12]  M. Delong,et al.  The riverine ecosystem synthesis: biocomplexity in river networks across space and time , 2006 .

[13]  J. Harvey,et al.  Reactive uptake of trace metals in the hyporheic zone of a mining- contaminated stream, Pinal Creek, Arizona , 2000 .

[14]  J. Kollmann,et al.  Large wood retention in river channels: the case of the Fiume Tagliamento, Italy , 2000 .

[15]  W. Junk.  The flood pulse concept in river-floodplain systems , 1989 .

[16]  C. Claret,et al.  Influence of benthic and interstitial processes on nutrient changes along a regulated reach of a large river (Rhône River, France) , 2001, Hydrobiologia.

[17]  C. Revenga,et al.  Fragmentation and Flow Regulation of the World's Large River Systems , 2005, Science.

[18]  G. Minshall,et al.  The River Continuum Concept , 1980 .

[19]  Jack A. Stanford,et al.  1 – Basic Attributes of Groundwater Ecosystems and Prospects for Research , 1994 .

[20]  Patrick J. Mulholland,et al.  Streams and Ground Waters , 1999 .

[21]  Andrew J. Boulton,et al.  Aquifers and hyporheic zones: Towards an ecological understanding of groundwater , 2005 .

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

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

[24]  A. Hill,et al.  Instream restoration: its effects on lateral stream–subsurface water exchange in urban and agricultural streams in Southern Ontario , 2007 .

[25]  Dennis D. Dauble,et al.  Redd Site Selection and Spawning Habitat Use by Fall Chinook Salmon: The Importance of Geomorphic Features in Large Rivers , 1998, Environmental management.

[26]  David S. White,et al.  Perspectives on Defining and Delineating Hyporheic Zones , 1993, Journal of the North American Benthological Society.

[27]  Jinxi Song,et al.  Effects of hyporheic processes on streambed vertical hydraulic conductivity in three rivers of Nebraska , 2007 .

[28]  M. D. Châtelliers.  Geomorphological processes and discontinuities in the macrodistribution of the interstitial fauna. A working hypothesis , 1991 .

[29]  B. Rossaro,et al.  A reference river system for the Alps: the ‘Fiume Tagliamento’ , 1999 .

[30]  A. Hill,et al.  Hyporheic exchange flows induced by constructed riffles and steps in lowland streams in southern Ontario, Canada , 2006 .

[31]  D. Dudley Williams,et al.  Factors controlling riffle‐scale hyporheic exchange flows and their seasonal changes in a gaining stream: A three‐dimensional groundwater flow model , 2003 .

[32]  The clogging of coarse gravel river beds by fine sediment , 1992 .

[33]  Klement Tockner,et al.  A landscape perspective of surface-subsurface hydrological exchanges in river corridors , 2002 .

[34]  J. Harvey,et al.  Modeling decadal timescale interactions between surface water and ground water in the central Everglades, Florida, USA , 2006 .

[35]  K. Bencala,et al.  The Effect of streambed topography on surface‐subsurface water exchange in mountain catchments , 1993 .

[36]  A. Packman,et al.  Interplay of stream‐subsurface exchange, clay particle deposition, and streambed evolution , 2003 .

[37]  M. Mutz,et al.  Processes of Surface-Subsurface Water Exchange in a Low Energy Sand-Bed Stream , 2003 .

[38]  L. Greenberg,et al.  Impact of short‐term regulation on hyporheic water quality in a boreal river , 2008 .

[39]  Aaron I. Packman,et al.  Effects of suspended sediment characteristics and bed sediment transport on streambed clogging , 2005 .

[40]  A. Butturini,et al.  Influences of the stream groundwater hydrology on nitrate concentration in unsaturated riparian area bounded by an intermittent Mediterranean stream , 2003 .

[41]  M. Mutz.  Influences of Woody Debris on Flow Patterns and Channel Morphology in a Low Energy, Sand‐Bed Stream Reach , 2000 .

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

[43]  L. Thibodeaux,et al.  Bedform-generated convective transport in bottom sediment , 1987, Nature.

[44]  Gregory B. Pasternack,et al.  Application of a 2D hydrodynamic model to design of reach‐scale spawning gravel replenishment on the Mokelumne River, California , 2004 .

[45]  P. Hancock,et al.  Human Impacts on the Stream–Groundwater Exchange Zone , 2002, Environmental management.

[46]  D. Williams,et al.  The occurrence of benthos deep in the substratum of a stream , 1974 .

[47]  Bernd Spänhoff,et al.  An experimental assessment of the effectiveness of gravel cleaning operations in improving hyporheic water quality in potential salmonid spawning areas , 2008 .

[48]  D. Gutknecht,et al.  Clogging Processes in Hyporheic Interstices of an Impounded River, the Danube at Vienna, Austria , 2003 .

[49]  S. Larned,et al.  Responses of hyporheic invertebrate assemblages to large-scale variation in flow permanence and surface–subsurface exchange , 2007 .

[50]  M. Kelly-Quinn,et al.  Optimising sample volume and replicates using the Bou-Rouch method for the rapid assessment of hyporheic fauna , 2009 .

[51]  E. Stanley,et al.  Process-Based Ecological River Restoration: Visualizing Three-Dimensional Connectivity and Dynamic Vectors to Recover Lost Linkages , 2006 .

[52]  J. Stanford,et al.  The serial discontinuity concept : extending the model to floodplain rivers , 1995 .