Effect of irrigation on a deep aquifer: a case study from the semi-arid Harran Plain, GAP Project, Turkey

摘要

Inappropriate irrigation practices are responsible for the deterioration of groundwater quality in a great number of developing countries, particularly in semi-arid and arid regions. The study was undertaken to determine the variation in groundwater quality of a deep aquifer after surface irrigation was started in the semi-arid Harran Plain, southeast Turkey. Physical and chemical parameters of the groundwater, including pH, temperature, electrical conductivity, sodium, potassium, calcium, magnesium, chloride, bicarbonate, sulphate and nitrate, were determined on a monthly basis from November 2008 to July 2009. The quality of the deep aquifer was assessed hydrochemically in order to determine its suitability for human consumption and agricultural purposes. With the exception of two wells, the measured and analyzed parameters in all the ground-water samples were below the internationally accepted maximum concentrations for human consumption and for agricultural purposes. The study identified a local contamination as a consequence of excess irrigation, high evaporation rates and drainage. It is hoped that the results will assist planners in the proper design and control of irrigation schemes to avoid further deterioration of these important aquifers.