1M. Sc. Student, Dept. of Water Engineering, Faculty of Water and Soil, University of Zabol, Iran.
2Assistant Prof., Dept. of Water Engineering, Faculty of Water and Soil, University of Zabol, Iran.
Abstract
Due to the importance of groundwater resources as useable and depleting water resources, the study and appropriate management of groundwater exploitation are very important. A proper management of groundwater resource needs knowledge of the spatial variability of water table levels over the study area. To obtain such information, appropriate interpolation and mapping of water table levels based on a limited number of observations is needed. Recently, geostatistical interpolators are being used as they have acceptable accuracy. In this study the performance of ordinary kriging (OK), inverse distance weighting (IDW), radial basis function (RBF) and global polynomial interpolation (GPI) for estimating groundwater level are compared. Water table data are related to a number of 31 observation levels across Zahedan plain recorded in 2011. Cross validation technique is used to compare the results with the evaluation criteria, root mean square error (RMSE) and mean bias error (MBE). Based on the results, OK with a Guassian model of semivariogram having the lowest amounts of RMSE (7.9 m) and MBE (-0.97 m) is the most accurate approach for estimating groundwater level over the study area. The generated water table map indicates that groundwater level in south and southwest of the study area is higher than its value in northern and northeastern parts.
