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The importance of surface controls on overland flow connectivity in semi-arid environments: results from a numerical experimental approach

Reaney, S.R.; Bracken, L.J.; Kirkby, M.J.

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Authors

L.J. Bracken

M.J. Kirkby



Abstract

In semi-arid environments, the characteristics of the land surface determine how rainfall is transformed into surface runoff and influences how this runoff moves from the hillslopes into river channels. Whether or not water reaches the river channel is determined by the hydrological connectivity. This paper uses a numerical experiment-based approach to systematically assess the effects of slope length, gradient, flow path convergence, infiltration rates and vegetation patterns on the generation and connectivity of runoff. The experiments were performed with the Connectivity of Runoff Model, 2D version distributed, physically based, hydrological model. The experiments presented are set within a semi-arid environment, characteristic of south-eastern Spain, which is subject to low frequency high rainfall intensity storm events. As a result, the dominant hydrological processes are infiltration excess runoff generation and surface flow dynamics. The results from the modelling experiments demonstrate that three surface factors are important in determining the form of the discharge hydrograph: the slope length, the slope gradient and the infiltration characteristics at the hillslope-channel connection. These factors are all related to the time required for generated runoff to reach an efficient flow channel, because once in this channel, the transmission losses significantly decrease. Because these factors are distributed across the landscape, they have a fundamental role in controlling the landscape hydrological response to storm events.

Citation

Reaney, S., Bracken, L., & Kirkby, M. (2014). The importance of surface controls on overland flow connectivity in semi-arid environments: results from a numerical experimental approach. Hydrological Processes, 28(4), 2116-2128. https://doi.org/10.1002/hyp.9769

Journal Article Type Article
Online Publication Date Mar 14, 2013
Publication Date Feb 15, 2014
Deposit Date May 7, 2013
Publicly Available Date Jan 27, 2015
Journal Hydrological Processes
Print ISSN 0885-6087
Electronic ISSN 1099-1085
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 28
Issue 4
Pages 2116-2128
DOI https://doi.org/10.1002/hyp.9769
Keywords Runoff, Hydrological connectivity, CRUM, Surface, Vegetation, Slope, Semi-arid, Overland flow.

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Copyright Statement
This is the accepted version of the following article: Reaney, S. M., Bracken, L. J. and Kirkby, M. J. (2014), The importance of surface controls on overland flow connectivity in semi-arid environments: results from a numerical experimental approach. Hydrological Processes, 28 (4): 2116-2128, which has been published in final form at http://dx.doi.org/10.1002/hyp.9769. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.







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