A network theory approach for a better understanding of overland flow connectivity

Hydrological connectivity describes the physical coupling (linkages) of different elements within a landscape regarding (sub-) surface flows. A firm understanding of hydrological connectivity is important for catchment management applications, for example, habitat and species protection, and for flood resistance and resilience improvement. Thinking about (geomorphological) systems as networks can lead to new insights, which has also been recognized within the scientific community, seeing the recent increase in the use of network (graph) theory within the geosciences. Network theory supports the analysis and understanding of complex systems by providing data structures for modelling objects and their linkages, and a versatile toolbox to quantitatively appraise network structure and properties. The objective of this study was to characterize and quantify overland flow connectivity dynamics on hillslopes in a humid sub-Mediterranean environment by using a combination of high-resolution digital-terrain models, overland flow sensors and a network approach. Results showed that there are significant differences between overland flow connectivity on agricultural areas and semi-natural shrubs areas. Significant positive correlations between connectivity and precipitation characteristics were found. Significant negative correlations between connectivity and soil moisture were found, most likely because of soil water repellency and/or soil surface crusting. The combination of structural networks and dynamic networks for determining potential connectivity and actual connectivity proved a powerful tool for analysing overland flow connectivity. Copyright © 2016 John Wiley & Sons, Ltd.

[1]  Patrick N. Halpin,et al.  Modeling population connectivity by ocean currents, a graph-theoretic approach for marine conservation , 2007, Landscape Ecology.

[2]  T. Heckmann,et al.  Geomorphic coupling and sediment connectivity in an alpine catchment - exploring sediment cascades using graph theory , 2013 .

[3]  Wolfgang Schwanghart,et al.  Graph theory-recent developments of its application in geomorphology , 2014 .

[4]  A. Cerdà,et al.  Effects of rock fragment cover on soil infiltration, interrill runoff and erosion , 2001 .

[5]  Anthony J. Parsons,et al.  Field measurement of the velocity of overland flow using dye tracing , 1986 .

[6]  Viral B. Shah,et al.  Using circuit theory to model connectivity in ecology, evolution, and conservation. , 2008, Ecology.

[7]  Mathieu Javaux,et al.  What indicators can capture runoff-relevant connectivity properties of the micro-topography at the plot scale? , 2009 .

[8]  J. Moody,et al.  Measurements of the initiation of post‐wildfire runoff during rainstorms using in situ overland flow detectors , 2015 .

[9]  G. Hancock,et al.  Modelling soil erosion with a downscaled landscape evolution model , 2012 .

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

[11]  Jacob Cohen,et al.  A power primer. , 1992, Psychological bulletin.

[12]  U. Brunner,et al.  Traffic control using graph theory , 1993 .

[13]  Stuart N. Lane,et al.  Representation of landscape hydrological connectivity using a topographically driven surface flow index , 2009 .

[14]  K. Kraus,et al.  Determination of terrain models in wooded areas with airborne laser scanner data , 1998 .

[15]  Hervé Squividant,et al.  Incorporating landscape features to obtain an object‐oriented landscape drainage network representing the connectivity of surface flow pathways over rural catchments , 2011 .

[16]  Claire Goulsbra,et al.  A new approach to the application of electrical resistance sensors to measuring the onset of ephemeral streamflow in wetland environments , 2009 .

[17]  John W. Pomeroy,et al.  Connectivity and runoff dynamics in heterogeneous basins , 2011 .

[18]  Mathieu Javaux,et al.  How do slope and surface roughness affect plot-scale overland flow connectivity? , 2015 .

[19]  Doerthe Tetzlaff,et al.  Concepts of hydrological connectivity: Research approaches, pathways and future agendas , 2013 .

[20]  Takaki Maekawa,et al.  Evolution and Conservation of Plant NLR Functions , 2013, Front. Immunol..

[21]  J. M. Laflen,et al.  Small Grain Cover Crops and Wheel Traffic Effects on Infiltration, Runoff, and Erosion , 2001 .

[22]  Wolfgang Schwanghart,et al.  TopoToolbox: A set of Matlab functions for topographic analysis , 2010, Environ. Model. Softw..

[23]  James P. McNamara,et al.  An approach to understanding hydrologic connectivity on the hillslope and the implications for nutrient transport , 2003 .

[24]  S. Galle,et al.  Overland flow and infiltration modelling for small plots during unsteady rain: numerical results versus observed values , 2000 .

[25]  Catherine M. Pringle.  The need for a more predictive understanding of hydrologic connectivity , 2003 .

[26]  André G. Roy,et al.  Shopping for hydrologically representative connectivity metrics in a humid temperate forested catchment , 2010 .

[27]  E. Addink,et al.  Network concepts to describe channel importance and change in multichannel systems: test results for the Jamuna River, Bangladesh , 2014 .

[28]  M. S. Srinivasan,et al.  SURFACE AND SUBSURFACE SENSORS TO RECORD VARIABLE RUNOFF GENERATION AREAS , 2000 .

[29]  T. Giambelluca,et al.  Hydrological consequences of landscape fragmentation in mountainous northern Vietnam: evidence of accelerated overland flow generation , 2004 .

[30]  M. López‐Vicente,et al.  Hydrological Connectivity Does Change Over 70 Years of Abandonment and Afforestation in the Spanish Pyrenees , 2017 .

[31]  Alan D. Howard,et al.  Topological and Geometrical Properties of Braided Streams , 1970 .

[32]  L. Basher,et al.  Role of wheel tracks in runoff generation and erosion under vegetable production on a clay loam soil at Pukekohe, New Zealand , 2001 .

[33]  J. Brasington,et al.  Modeling the topography of shallow braided rivers using Structure-from-Motion photogrammetry , 2014 .

[34]  A. Parsons,et al.  Hydrologic and sediment responses to simulated rainfall on desert hillslopes in southern Arizona , 1988 .

[35]  A. Parsons,et al.  Impact of connectivity on the modeling of overland flow within semiarid shrubland environments , 2007 .

[36]  Willem Bouten,et al.  Segmentation optimization and stratified object-based analysis for semi-automated geomorphological mapping , 2011 .

[37]  C. Werner,et al.  EXPLORATIONS INTO THE FORMAL-STRUCTURE OF DRAINAGE BASINS , 1994 .

[38]  Caspar J. M. Hewett,et al.  Modelling and managing critical source areas of diffuse pollution from agricultural land using flow connectivity simulation , 2005 .

[39]  C. Gascuel-Odoux,et al.  Evolution of soil surface roughness and flowpath connectivity in overland flow experiments , 2002 .

[40]  Ronald E. Poeppl,et al.  The influence of riparian vegetation cover on diffuse lateral sediment connectivity and biogeomorphic processes in a medium‐sized agricultural catchment, austria , 2012 .

[41]  E. Foufoula‐Georgiou,et al.  A network‐based framework for identifying potential synchronizations and amplifications of sediment delivery in river basins , 2014 .

[42]  C. Gascuel-Odoux,et al.  Hillslope topographic and hydrologic effects on overland flow and erosion , 2002 .

[43]  Dean L Urban,et al.  Graph theory as a proxy for spatially explicit population models in conservation planning. , 2007, Ecological applications : a publication of the Ecological Society of America.

[44]  Artemi Cerdà,et al.  The influence of slope angle on sediment, water and seed losses on badland landscapes , 1997 .

[45]  Averaging Performance of Capacitance and Time Domain Reflectometry Sensors in Nonuniform Wetted Sand Profiles , 2014 .

[46]  A. Lucieer,et al.  Unmanned aerial vehicle (UAV) remote sensing for hyperspatial terrain mapping of Antarctic moss beds based on structure from motion (SfM) point clouds , 2011 .

[47]  Susana Bautista,et al.  Plant Spatial Pattern Predicts Hillslope Runoff and Erosion in a Semiarid Mediterranean Landscape , 2007, Ecosystems.

[48]  Wolfgang Schwanghart,et al.  Fuzzy delineation of drainage basins through probabilistic interpretation of diverging flow algorithms , 2012, Environ. Model. Softw..

[49]  John Wainwright,et al.  Scale relationships in hillslope runoff and erosion , 2006 .

[50]  T. Stepinski,et al.  Geomorphons — a pattern recognition approach to classification and mapping of landforms , 2013 .

[51]  S. Keesstra,et al.  Assessing riparian zone impacts on water and sediment movement: a new approach , 2012, Netherlands Journal of Geosciences - Geologie en Mijnbouw.

[52]  T. Heckmann,et al.  Graph theory in the geosciences , 2015 .

[53]  Arnaud J.A.M. Temme,et al.  Modelling Discharge and Sediment Yield at Catchment Scale Using Connectivity Components , 2016 .

[54]  Timothy H. Keitt,et al.  Landscape connectivity: A conservation application of graph theory , 2000 .

[55]  J. Poesen,et al.  Effects of rock fragment covers on erosion and transport of noncohesive sediment by shallow overland-flow , 1993 .

[56]  J. Hamlett,et al.  Dynamics of stormflow generation—A hillslope‐scale field study in east‐central Pennsylvania, USA , 2002 .

[57]  M. Westoby,et al.  ‘Structure-from-Motion’ photogrammetry: A low-cost, effective tool for geoscience applications , 2012 .

[58]  R. L. Shreve,et al.  Variation of mainstream length with basin area in river networks , 1974 .

[59]  J. McDonnell,et al.  Hewlett, J.D. and Hibbert, A.R. 1967: Factors affecting the response of small watersheds to precipitation in humid areas. In Sopper, W.E. and Lull, H.W., editors, Forest hydrology, New York: Pergamon Press, 275—90 , 2009 .

[60]  Örjan Bodin,et al.  Closing the collaborative gap: Aligning social and ecological connectivity for better management of interconnected wetlands , 2015, AMBIO.

[61]  Arie C. Seijmonsbergen,et al.  Geomorphological Change Detection Using Object-Based Feature Extraction From Multi-Temporal LiDAR Data , 2013, IEEE Geoscience and Remote Sensing Letters.

[62]  S. Trevisani,et al.  Topography-based flow-directional roughness: potential and challenges , 2015 .

[63]  Ferenc Jord,et al.  Network ecology: topological constraints on ecosystem dynamics , 2004 .

[64]  Geert Sterk,et al.  The effectiveness of soil conservation measures at a landscape scale in the West Usambara highlands, Tanzania , 2015 .

[65]  Simon Mockler,et al.  Sediment concentration changes in runoff pathways from a forest road network and the resultant spatial pattern of catchment connectivity , 2005 .

[66]  L. H. Cammeraat,et al.  Scale dependent tresholds in hydrological and erosion response of a semi-arid catchment in Southeast Spain , 2004 .

[67]  T. G. Freeman,et al.  Calculating catchment area with divergent flow based on a regular grid , 1991 .

[68]  Timothy H. Keitt,et al.  LANDSCAPE CONNECTIVITY: A GRAPH‐THEORETIC PERSPECTIVE , 2001 .

[69]  Theodore A. Endreny,et al.  Maximizing spatial congruence of observed and DEM-delineated overland flow networks , 2003, Int. J. Geogr. Inf. Sci..

[70]  Jesús Álvarez-Mozos,et al.  Runoff, erosion, and water quality of agricultural watersheds in central Navarre (Spain) , 2008 .

[71]  John Wainwright,et al.  Plot-scale studies of vegetation, overland flow and erosion interactions: case studies from Arizona and New Mexico , 2000 .

[72]  Juan M. Díez,et al.  Factors controlling sediment export in a small agricultural watershed in Navarre (Spain) , 2012 .

[73]  Andres Peñuela,et al.  Evolution of overland flow connectivity in bare agricultural plots , 2016 .

[74]  Julian D. Olden,et al.  ELECTRICAL RESISTANCE SENSOR ARRAYS AS A MEANS TO QUANTIFY LONGITUDINAL CONNECTIVITY OF RIVERS , 2012 .

[75]  Jean Poesen,et al.  Laboratory experiments on the influence of slope length on runoff, percolation and rill development , 1989 .

[76]  R. J. Loch,et al.  Effects of vegetation cover on runoff and erosion under simulated rain and overland flow on a rehabilitated site on the Meandu Mine, Tarong, Queensland , 2000 .

[77]  J. Wainwright,et al.  Linking environmental régimes, space and time: Interpretations of structural and functional connectivity , 2008 .

[78]  Richard T. T. Forman,et al.  Landscape graphs: Ecological modeling with graph theory to detect configurations common to diverse landscapes , 1993, Landscape Ecology.

[79]  Mark Newman,et al.  Networks: An Introduction , 2010 .