Evaluation of a surface hydrological connectivity index in agricultural catchments

Shore, M. and Murphy, P. N. C. and Jordan, P. and Mellander, P. -E. and Kelly-Quinn, M. and Cushen, M. and Mechan, S. and Shine, O. and Melland, A. R. (2013) Evaluation of a surface hydrological connectivity index in agricultural catchments. Environmental Modelling and Software, 47. pp. 7-15. ISSN 1364-8152


Identification of surface hydrological connectivity at scales where critical source areas (CSAs) can be managed is fundamental to achieving effective management of phosphorus loss in agricultural catchments. This study investigated the potential for the 'Network Index' (NI) to predict surface connectivity at CSA-management scales in contrasting agricultural catchments (ca. 1200ha) using a 5m DEM. One catchment had mostly permeable soils and a low surface ditch density. The other catchment had mostly impermeable soils and a high surface ditch density. The importance of surface ditch data for accurately modelling the location and magnitude of surface connectivity was also evaluated. Modelled surface connectivity at the subcatchment scale (ca. 130ha) was validated using observed channel (ditch and stream) densities. Modelled surface connectivity at the field scale (ca. 2ha) was evaluated using four indicators of observed field connectivity. At the subcatchment scale, modelled surface connectivity matched observations well (R2=0.52) despite the soil type variability across catchments. However, some errors in subcatchment boundary delineation (total of 133ha in one catchment) occurred which could distort the extent of predicted CSAs. At the field scale, the NI had potential for broadly discerning the most connected from the least connected fields which is valuable for identifying where CSA-based management should be targeted. Detailed ditch information was required to accurately delineate subcatchment boundaries; however, it was not needed for predicting subcatchment connectivity.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2013 Elsevier Ltd. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 17 Aug 2014 23:34
Last Modified: 07 Mar 2017 04:24
Uncontrolled Keywords: critical source areas; CSA; DEM; drainage ditches; network index; NI; surface connectivity; TWI
Fields of Research : 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070105 Agricultural Systems Analysis and Modelling
05 Environmental Sciences > 0503 Soil Sciences > 050302 Land Capability and Soil Degradation
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Identification Number or DOI: 10.1016/j.envsoft.2013.04.003
URI: http://eprints.usq.edu.au/id/eprint/25780

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