A hydrological-climatological-ecological drought severity index

Droughts are studied either from a pure climatological prespective (precipitation deficit), hydrological perspective (low streamflow) or ecological perspective (low vegetation). This paper intends to study droughts and their occurences using a hydrological model of the soil layers complete with infiltration, runoff, evaporation and temporal evolution of the soil moisture. We propose a new method of integration of precipitation, soil moisture, streamflow, water table and vegetation information into an integrated hydrological-climatological-ecological drought severity index. However, several roadblocks exist for such a coupled index. Water table information (if available) is very sparse and these are influenced by withdrawls. Vegetation data is available via remote sensing and is very seasonal. Precipitation is highly variable in space and has this has to be factored in the index calculation. This paper will provide a framework for such a complex and complete integration.