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Abstract
Makhmour hydrogeological basin is considered as one of the important basins in North of Iraq which depends upon groundwater for irrigation. The demands of groundwater has increased due to extension of the irrigated lands, and lack of surface water beside there is no any irrigation project in the basin which was proposed to provide surface water to the farms. The suitability of groundwater for irrigation depends mainly upon many constrains factors (EC, SAR, Na%, Cl, SO4). Many classifications were presented to understand the groundwater suitability for agriculture; these early irrigation water suitability criteria have received strong criticism due to undefined clear cut boundaries between different classes of irrigated water. The aim of this work is to present a classification for groundwater suitability for agriculture by using Arc GIS which provides tools to create a conceptual model for solving spatial problems. A set of conceptual steps used to build a model for suitability map of groundwater for irrigation. 3D spatial analyst can interpolate the data of five of constrain factor into rasters .The rasters are reclassified by grouping ranges of values into single value. Analytical Hierarchy Process (AHP) is used for calculating the influence (weight) of each constrain factor, after using weighted overlay in GIS , a final raster is the output instead of different rasters shows spatial extent of groundwater suitability for agriculture. Five classes was distinguished in Makhmour basin after analysis the data of 33 groundwater samples, the suitability ranged between “1 – 5″ (Excellent – Unsuitable).
Keywords: Groundwater, GIS, Reclassification, AHP, weighted overlay
