Modeling of drought effect on the Total Hardness and Total Dissolved Solids inground water of Mashhad plain

Water is the major challenging issue worldwide. In Iran, water shortage is more serious than other countries because it is located on arid and semi-arid region. The objective of this research was modeling of drought effects on variation of chemical water quality in the wells of Kashaf Rood area in Mashhad plain in 2006-2010. Quality and levelraw data(2006-2010) of 16 drinking water wells in Kashaf Rood area and also meteorological parameters were extracted. Data were analyezed by SPSS and Excel softwares and modeled was by STELLA software.Normal and Pearson corrolate test were used in significance level α= 0.05, to understand relationship between water level and quality. Ground water level from 2006 to 2010 have had 6 meter loss. Mashhad plain experienced the least rainfall with an average annual 104.7 mm in 1998-99 and the most rainfall with an minimum annual 414.6 mm. Maximum temperature have been 35 to 40 0C in the hot months and also shortage rain and intensive water level loss were observed in these months in 1991-1992. Examination between water level variation and water ground indexes (TDS & TH) determined that all wells had no significant relationship between those parameters except wells No 5(p=0.028) and 9 (p=0.024). According to model results could be concluded model have good accuracy to estimate groundwater characteristics concentration. Mentioned ground water level loss in the area indicates need for appropriate planninig and management of water resources and rainfall so that will be prevented direct and indirect drought (ie: quality change).