In this research, to assess the hydrogeological drought situation, a new index, Groundwater Resource Index (GRI), was used for spatial and temporal examination of hydrogeological trend of drought with use of groundwater level data in two steps. In the first step, to examine the hydrogeological temporal drought trend in the wells, three wells with the maximum, minimum and moderate drop in groundwater level, were selected. Results showed that in water-abundance peak the drought that equals to GRI becoming negative starts during 2003 in well No. 10 and during 2000 in well No. 18. GRI value in well No. 16 was negated once during 2002 and once during 2004. In water shortage peak the drought which equals to GRI becoming negative starts during 2004 in well No. 10 and during 2000 in well No. 18. GRI value in well No. 16 was negated once during 2002 and once during 2008. In second step, to develop a spatial overview from each point within the study area, due to the scattering monitoring wells, kriging method was used to draw the iso GRI value maps and to interpolate the GRI values. Results showed that there is no steady trend for GRI changes in the whole plain due to the changes in the surface constituents' substance, surface topography, the bedrock and the exploitation of groundwater resources. Furthermore, results showed that GRI values were negative in 2008 all over the plain, and with the passage of time, harsher drought is going to occur to the northwest of plain.

Geographic information system (GIS); Groundwater Resource Index (GRI); Groundwater level; Hydrogeological drought; Monitoring

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia