The influence of land use, soils and topography on the delivery of hillslope runoff to channels in SE Spain

Abstract

It is generally accepted that within particular physiographic and climatic regions catchments exhibit differences in their hydrological response. These differences result from the interaction of spatial variability in catchment characteristics, variability of rainfall inputs and surface and subsurface hydrological processes. These interactions are complex and difficult to unravel. Hydrologically similar surfaces (HYSS) have been used to identify catchment areas that have a similar response to rainfall and have been identified at a number of scales. HYSS have been identified at the subcatchment scale for the Rambla de Nogalte in SE Spain. Areas with similar at-a-point hydrological storages were distinguished by using a combination of geology, land use and topography. This mapping was compared with discharge estimates made throughout the catchment following a seven-year return interval flood in September 1997. From this significant flood source areas were identified from reaches showing rapidly increasing channel discharge, and associated with HYSS that combined suitable internal characteristics with good connectivity to the main channel. This paper presents a simulation model that has been developed to investigate the way in which the hydrological response of areas within a HYSS respond to changes in source area, gradient, connectivity to the channel, storm size and intensity profile. This is one of the first studies using a hillslope model to investigate spatial patterns of runoff-response in semi-arid areas and results have implications for scaling up hydrological response, and on how the dynamics of runoff producing areas vary both under changing storm conditions and over time. It is implicit in our results that the nature of stream-slope coupling differs substantively between semi-arid and humid areas.

Erosion in Mediterranean landscapes: Changes and future challenges

“…The following step is to understand how to reduce the connectivity between the most eroded areas and channels, and how to promote new water and sediment sinks (Kirkby et al, 2002;Latron et al, 2009). The purpose of this is to reduce sediment outputs, and to take targeted action on selected hillslopes to progressively reduce the area of sediment sources.…”

Assessing sedimentological connectivity using WATEM/SEDEM model in a hilly and gully watershed of the Loess Plateau, China

“…With a longer flow path to the sinks, there is a higher probability that sediment will be trapped by impedances (Kirkby, 2001;Kirkby et al, 2002;Blanco-Canqui et al, 2004;Rey, 2004) and, therefore, the SEAs close to sinks contribute more sediment. As illustrated by the distribution of SW (Fig.…”

A comparative study of nutrient transfer via surface runoff from two small agricultural catchments in north China

“…It can reduce overland flow velocity, and surface water ponds in small depressions (Bergkamp 1998;Kirkby et al 2002;Cammeraat 2004;Imeson and Prinsen 2004). Micro-topographical features can be differentiated as source and sink features.…”

“…In a catchment with high spatial heterogeneity, various landscapes and patches can be categorized as ''source'' or ''sink'' landscapes and patches according to their roles of transportation or detention. The number and spatial patterns of source and sink landscapes and patches within a catchment can affect hydrological and nutrient transport processes at different scales (Mander et al 2000;Chen et al 2002;Kirkby et al 2002;Imeson and Prinsen 2004;Ngoye and Machiwa 2004;Chen et al 2005).…”

“…A number of previous studies conducted in the Mediterranean with a semiarid climate showed that micro-topography could exert a great impact on surface runoff generation, soil erosion, and vegetation pattern at the finer scale (Bergkamp 1998;Kirkby et al 2002;Cammeraat 2004;Imeson and Prinsen 2004). Bergkamp (1998) measured runoff and infiltration to understand the relationship between runoff production, vegetation pattern and microtopography at five spatial scales from terracette (<1 m) to catchment (50 ha).…”