Reducing the Vulnerability of Societies to Water Related Risks at the Basin Scale (Proceedings of the third International Symposium on Integrated Water Resources Management, Bochum, Germany, September 2006). IAHS Publ. 317, 2007, 3–8.

Hydrological interdependencies of irrigation systems and river catchments

MAURITS ERTSEN¹, DANIEL PRIETO² & NICK VAN DE GIESEN¹

1 Water Resources, Delft University of Technology, PO Box 5048, 2600GA Delft, The Netherlands

m.w.ertsen@tudelft.nl

2 Instituto Nacional de Tecnología Agropecuaria, Santiago del Estero, Argentina

Abstract This paper discusses (re)distributing effects of small and large irrigation systems at the catchment scale. Scales of catchment and system, each with their own temporal and spatial properties, are to be integrated. To be able to quantify water fluxes in irrigation, water fluxes within the system at canal and field level need to be understood. Two cases are presented. The first case study on large-scale irrigation in Argentina shows how the properties of the system, expressed in a scattered pattern of water distribution within and along the borders of the irrigated area, influence the spatial distribution of evapo­transpiration. The second case study, on small-scale sand dams in Kenya shows that the scales of catchment and system need to be linked to understand the dynamics of human intervention and hydrological behaviour of catchments.

Key words Argentina; catchment scale; field scale; fluxes; irrigation; Kenya; redistribution effects; system scale