Distributed assessment of contributing area and riparian buffering along stream networks

[1] We present a simple approach for quantifying the local contributions of hillslope area and riparian area along a stream network based on gridded digital elevation data. The method enables one to compute catchment characteristics such as the distribution of riparian and hillslope inputs to the stream network, the variation of riparian-area percentage along the stream network, and subcatchment area distributions. We applied the technique to the 280-ha Maimai research area in New Zealand. We found that 85% of the catchment area contributed to streams with a local catchment area of <20 ha, whereas only 28% of the riparian area was found along these small streams. The potential of riparian zones to buffer hillslope runoff depends partially on the size of the riparian zone relative to the adjacent hillslope or upland area. Our approach enables calculation of a spatially distributed measure of riparian to hillslope area ratios. At the 280 ha Maimai research area we found that the ratio between riparian and hillslope area was 0.14. When we calculated this “buffer capacity” for each 20 m stream reach along the stream network, the values were below 0.14 for 75% of the stream length and the median was 0.06. Using the catchment-wide ratio would thus significantly overestimate the “effective” riparian-to-hillslope-area ratio.

[1]  J. McDonnell,et al.  Quantifying contributions to storm runoff through end‐member mixing analysis and hydrologic measurements at the Panola Mountain Research Watershed (Georgia, USA) , 2001 .

[2]  M. Mosley.  Streamflow generation in a forested watershed, New Zealand , 1979 .

[3]  Kevin Devito,et al.  Groundwater-surface water interactions in headwater forested wetlands of the Canadian Shield , 1996 .

[4]  R. Betson.  Drainage Basin Form and Process A Geomorphological Approach , 1974 .

[5]  Paul D. Bates,et al.  Numerical simulation of floodplain hydrology , 2000 .

[6]  William E. Dietrich,et al.  The Channel head , 1993 .

[7]  Brian L. McGlynn,et al.  A review of the evolving perceptual model of hillslope flowpaths at the Maimai catchments, New Zealand , 2002 .

[8]  M. P. Mosley,et al.  Subsurface flow velocities through selected forest soils, South Island, New Zealand , 1982 .

[9]  D. Weyman,et al.  THROUGHFLOW ON HILLSLOPES AND ITS RELATION TO THE STREAM HYDROGRAPH , 1970 .

[10]  M. Brinson.  Riparian ecosystems: their ecology and status , 1981 .

[11]  A. Hill.  Ground water flow paths in relation to nitrogen chemistry in the near-stream zone , 1990, Hydrobiologia.

[12]  Alan R. Hill,et al.  Nitrate Removal in Stream Riparian Zones , 1996 .

[13]  R. Woods,et al.  A connection between topographically driven runoff generation and channel network structure , 1997 .

[14]  J. Leprun,et al.  Relations between soil colour and waterlogging duration in a representative hillside of the West African granito-gneissic bedrock , 2000 .

[15]  J. Hewlett.  Factors affecting the response of small watersheds to precipitation in humid areas , 1967 .

[16]  K. Beven,et al.  A physically based, variable contributing area model of basin hydrology , 1979 .

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

[18]  Timothy A. Quine,et al.  Fluvial Processes and Environmental Change , 1999 .

[19]  W. Mitsch,et al.  Wetlands. 2nd ed. , 1993 .

[20]  Keith Beven,et al.  Riparian control of stream-water chemistry: Implications for hydrochemical basin models , 1998 .

[21]  J. McDonnell,et al.  Riparian zone flowpath dynamics during snowmelt in a small headwater catchment , 1999 .

[22]  K. Beven,et al.  The hydrological response of headwater and sideslope areas / La réponse hydrologique des zones de cours supérieurs et des zones de pente latérale , 1978 .

[23]  Ralph A. Leonard,et al.  Managing riparian ecosystems to control nonpoint pollution , 1985 .

[24]  R. Allan Freeze,et al.  Role of subsurface flow in generating surface runoff: 2. Upstream source areas , 1972 .

[25]  D. Montgomery,et al.  Digital elevation model grid size, landscape representation, and hydrologic simulations , 1994 .

[26]  K. Devito.  Sulphate mass balances of Precambrian Shield wetlands; the influence of catchment hydrogeology , 1995 .

[27]  D. Tarboton.  A new method for the determination of flow directions and upslope areas in grid digital elevation models , 1997 .

[28]  A. Hill.  3 – Stream Chemistry and Riparian Zones , 2000 .

[29]  Jeffrey J. McDonnell,et al.  Role of discrete landscape units in controlling catchment dissolved organic carbon dynamics , 2003 .

[30]  A. Pearce,et al.  Storm runoff generation in humid headwater catchments 1 , 1986 .

[31]  K. Richards.  The magnitude-frequency concept in fluvialgeomorphology: a component of a degenerating research programme? , 1999 .

[32]  W. H. Patrick,et al.  Wetland Identification in Seasonally Flooded Forest Soils: Soil Morphology and Redox Dynamics , 1993 .

[33]  Jeffrey J. McDonnell,et al.  Linking the hydrologic and biogeochemical controls of nitrogen transport in near-stream zones of temperate-forested catchments: a review , 1997 .

[34]  Christian Walter,et al.  Mapping waterlogging of soils using digital terrain models , 1995 .

[35]  J. Foss,et al.  Soil-Landscape relationships at the lower reaches of a watershed at Bear Creek near Oak Ridge, Tennessee , 2001 .

[36]  K. Beven,et al.  The in(a/tan/β) index:how to calculate it and how to use it within the topmodel framework , 1995 .

[37]  Malcolm G. Anderson,et al.  The role of topography in controlling throughflow generation , 1978 .