Modelling the spatial distribution and depletion of groundwater level in Tabriz plain

Due to high salinity of surface waters in Tabriz plain, which is one of the major concerns about irrigation and sustainable agriculture in the area, farmers exploit groundwater as supplement for surface water to irrigate their fields. This study aimed to apply Algebraic and Geo-statistical models for mapping groundwater depth through Tabriz plain over a period of 13 years (1380 to 1392) using data collected from 42 piezometric wells. Used models include Inverse Distance Weighted (IDW) and Radial Basis Functions (RBF), as representative of algebraic methods and Kriging as representative of Geo-statistical methods. Selection of appropriate method and validation of models were done by means of cross validation, mean bias error (MBE), root mean square error (RMSE) and coefficient of determination (R2). Results indicated that Kriging is more precise than other methods for zoning mapping the depth of groundwater, and the output map corresponds highly with land use, drainage networks, geology and through the study area. So, the method is considered to as the best model to zoning mapping the groundwater depth through Tabriz plain. Also, comparison of groundwater depth zoning maps over examined periods is indicative of an increase in groundwater depth in Southeast, East, South and partly North of the study area. This increase of groundwater depth could be related to improper exploitation of groundwater resources considering given garden lands located on the parts of the study area