HR: 08:30h
AN: H51H-03    [Abstracts]
TI: Thresholds for runoff and sediment transport in Semi-arid areas; implications for connectivity
AU: * Bracken, L J
EM: L.J.Bracken@Durham.ac.uk
AF: Durham University, Department of Geography Durham University, Durham, DH1 3LE, United Kingdom
AU: Kirkby, M J
EM: m.j.kirkby@leeds.ac.uk
AF: Leeds University, School of Geography University of Leeds, Leeds, LS2 9JT, United Kingdom
AB: The concept of connectivity is increasingly being applied within a range of disciplines in the Earth and Environmental sciences as researchers recognize the need to move beyond the traditional view that runoff is generated by either Hortonian infiltration excess or by the variable source area model. In studies which focus on connectivity two key assumptions tend to be made. Firstly, that runoff thresholds must be exceeded for runoff to be produced and secondly, that all factors that influence runoff thresholds are important for hydrological connectivity. It follows that hillslope hydrological connectivity can be initiated by shorter duration, or lower intensity events, whereas catchment-scale hydrological connectivity and flooding, requires prolonged, high intensity storms. Each catchment thus has a base spatial pattern in terms of connectivity, depending on key runoff generating areas, and a response curve as the catchments wets up. In this paper we explore how this base spatial pattern changes according to thresholds in the landscape for runoff generation and sediment transport. By examining a range of events at different spatial scales it is hoped that an understanding can be developed of key thresholds in semi-arid landscapes which will assist in understanding long term landscape development.
DE: 1804 Catchment
DE: 1815 Erosion
DE: 1824 Geomorphology: general (1625)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: 2007 Joint Assembly