RETRACTED ARTICLE: Variographic analysis of chemical and piezometric data from the sandstone aquifer of Ain Oussera, Algeria

The perturbation of piezometric level and the bad water quality in Ain Oussera plain represents a serious problem for local authorities and water resources managers. The spatial distribution of piezometric level and chemical data was analyzed by applying geostatistical methods, which provide an indication of the uncertainty of the estimation using the computer software VARIOWIN 2.2 (Pannatier 1996 ). In this paper, the evolution of the piezometric level and hydrochemical data by referring to other research campaigns was studied. Two campaigns were chosen; September 2001 and May 2008 for pizometric level and 1994 and 2004 for chemical data. In the beginning, elementary statistics has been carried out to understand the statistical distribution and performed an analysis of variance for comparison between two campaigns. Geostatistics for modeling and cartography were applied. The results showed that piezometric levels admit spherical model that the direction of groundwater flow is from southwest to northeast. High nugget effect characterizes piezometric data and chemical data, linked to the presence of microregions due to excessive pumping and local evaporitics formations. Anisotropy is observed in the northeast-southeast direction from which a spatial continuity in this direction can be deduced.