Lag_Time and Effect of Meteorological Drought on the Groundwater Level

Drought is an atmospheric phenomenon that can effect on various parts of the environment. Groundwater resources is the drought-affected sectors which less are considerate than other sectors. Aspas Plain in Fars province in recent years have a significant reduction in groundwater levels. So, the role of management in this plain is important. In this research, we use a cross-correlation function (CCF) for investigating long-and short-term drought on groundwater resources. For this purpose, the standardized precipitation index (SPI) Monthly (one, three, six, nine, 12, 18, 24 and 48 months) in the period (1985-2010) was calculated, also groundwater resources index (GRI) of the plain during the statistical period (2002-2010) were obtained from 61 wells in the plain. Cross-correlation function showed that short-term drought with delay and long-term drought simultaneously have been effected on ground water resource. Most relationship is between groundwater and SPI 24, which linear regression results showed that almost 80 percent of the average variance water table of Aspas Plain affected by changes in rainfall (SPI 24) and nearly 20 percent of it is influenced by other items.