Investigating the temporal variation and meteorological drought effect on groundwater resources in Kerman plain using SPI and GRI indices

Whereas climatic parameters find importance due to their impacts on water resources, therefore this research was done carried out for investigating of meteorological drought and its impacts on Kerman groundwater resources in the eighteen- year’s period (1997-2014). In this regard Standardized Precipitation Index (SPI) values in Kerman meteorological station and Groundwater Resource Index (GRI) of plain in different time scales (1, 3, 6, 9, 12, 18, 24 and 48 months) was calculated. The results of correlation test between GRI index in different time scales and SPI index in the time period under research without any delay and with a time lag of one to twelve months showed that 6 and 18 months GRI index have significantly related to 48 month SPI index with 0.628 and 0.631 Pearson coefficients, respectively and also 48 months GRI index was correlated to 48 months SPI index with 6 month lag time and its Pearson coefficient was 0.686. The results of regression model showed that up to 57 percent of variations in GRI index explained and justified by SPI index. This is due to other factors such as uncontrolled exploitation of groundwater resources on the loss of groundwater and groundwater index linked. Iso-decline maps showed that the decline in groundwater levels across the plain, an average of 20 meters and rising in ground water levels in the range of Kerman city by 14 meters.