Hydrological modeling to assess the link between water availability and vegetation growth

INGRID TEICH; CESAR LUIS GARCÍA; ELSE SWINNEN; CAROLIEN TOTE; ANA PLANCHUELO; MÓNICA BALZARINI

Research Award for Young Scholars 2011. Adaptative Water Management: looking to the future

Rocha Sampaio R., Mojardim Barbosa M., Iglesias Peralta A.

Lugar: Río de Janeiro; Año: 2011; p. 65 - 79

In the face of climate change and for sustainable management of arid areas, it is crucial to understand the link between water availability and vegetation growth. This linkage is often investigated using time series of rainfall data and a vegetation index from satellite sensors (e.g. NDVI). However, rainfall alone is not sufficient to describe available water for vegetation, and other bio-geophysical factors should be taken into account. Hydrological modeling offers a powerful tool for this purpose. In this study, hydrological response units (HRU) delineated in a distributed hydrological model system (JAMS), were used to compute a complete water balance and to assess the vegetation response to climatic variability in a Mountain Basin (Córdoba, Argentina). Vegetation changes were analyzed through NDVI time series from SPOTVEGETATION images over the 12 year period 1998-2009. Precipitation was always the least correlated variable to vegetation growth, except in less vegetated rocky areas. Synchrony of the vegetation growth with soil water saturation was found to be more direct (less delay), specially in grasslands. Our results show that hydrological modeling can aid in the study of vegetation response to climate variability, high lightening the importance of taking into account other factors that influence water availability besides precipitation.