Evaluation of geostatistical methods for mapping groundwater quality in Fars province

Subject Areas : Farm water management with the aim of improving irrigation management indicators

Vahid  Ghafoori ¹ (M.Sc. graduated of water resources engineering, Islamic Azad University, Shiraz branch, Shiraz, Iran)
Nosratolahe  Malekpour ² (manager of developing irrigation networks, Fars Jahade Keshavarzi)
Amin  Mardani ³ (M.Sc. graduated of irrigation and drainage, Tehran University)

Received: 2011-05-11 Accepted : 2011-09-20 Published : 2012-03-02

Keywords: Cokriging, groundwater quality, IDW, Kriging,

Abstract :

Geostatistical methods are one of the most advanced techniques for monitoring of groundwater quality. In this research, we compare efficiency of three interpolation techniques namely IDW, kriging, and cokriging for predicting a few groundwater quality indices such as: Na+, TH, EC, SAR, Cl-, Ca2+, Mg2+ and SO4. Data were gathered from 75 wells in Darab district, of Fars province. After normalizing the data, variograms were computed. A suitable model of fitness on experimental variogram was selected which was based on least RMSE value. Then the best method for interpolation was selected, using cross-validation and RMSE. Results showed that for all groundwater quality indices, cokriging performed better than other methods in simulating groundwater quality indices. Finally, using cokriging method, maps of Groundwater quality were prepared in GIS environment.