Spatial and temporal evaluation of depth and salinity of the groundwater in a large irrigated area in Southern Turkey

Abstract

It is of high importance to monitor groundwater level and salinity in wide irrigated farming lands. This is because high levels of groundwater and salinity in irrigated lands are major constraints for sustainable agriculture. Thus, this work undertaken aims at monitoring spatial and temporal changes of groundwater level and salinity in irrigated large farm lands. The research work was implemented in Akarsu Irrigation District (Akarsu ID) which is located in Southern Turkey, Lower Seyhan Plain (LSP) in 2007 hydrologic year. During 2007 hydrologic year, depths to water levels in groundwater wells (m) and groundwater salinity, as electrical conductivity (EC, dS m-1) were measured through five-month-period; from January to October. The results of depth (m) and salinity analysis (dS m-1) of the groundwater wells were mapped using geographical information system. In addition, cropping pattern and crop water requirements of the study area were specified. The results showed that groundwater reached to a critical threshold level in February because of heavy rains. It was noted that there were not any drainage problems in May. In July, however, the drainage problem was the worst. On the other hand, average groundwater salinity levels were higher in May, in early irrigation season, than July and October. The areas in which groundwater salinity was higher than the critical level (i.e., EC > 5 dS m-1) covered 19.2% of the total area in May, 17.7% in July, and 15.5% in September. During the study period, irrigation efficiency was indeed very low, 33.4%. Depending on the research findings, the drainage problem was the highest level in July. It is recommended that present practice of irrigation management is changed.