The impact of the warm phase of ENSO (El Niño Southern Oscillation) events on water resource availability of tropical catchments in Central Sulawesi, Indonesia

Abstract

Abstract. Precipitation anomalies caused by the warm phase (El Niño) of the ENSO cycle lead to a strong decrease of water resources in South-East Asia. The aim of this work is to study the impact of warm phase ENSO caused precipitation anomalies on the water balance of a mesoscale tropical catchment in Central Sulawesi, Indonesia using a scenario analysis. We applied statistically generated precipitation anomalies caused by warm phase ENSO events on a validated hydrological model of the Palu River catchment (2694 km2) to investigate the implications of the generated ENSO scenarios on the total annual water balance, the annual discharge regime and the discharge variability. Moreover we analysed the influence of various catchment characteristics during warm phase ENSO conditions on the discharge variability through a comparison of different sub-catchment types. The results of the scenario analysis proved a severe decline of the annual discharge rate during warm phase ENSO conditions and an increase of the overall discharge variability.