Groundwater Suitability Assessment for Irrigation Purposes Using GIS in Wadi Al-Khur Western Iraq.

Irrigation Water Quality Index (TWQI) for groundwater within the Geographic information system (GIS) environment is proposed so that it can be used in assessing the groundwater vulnerability. The model was applied in the Wadi Al-Khur the western part of Iraq. Thirty six sites were chosen for the investigation of Dammam water aquifer. Duplicate ground water samples were collected from each site during dry Season (Oct. 2011) and wet season (Apr. 2012). Variables tested in each samples includes: pH, EC, total hardness Ca , Mg , CI, Na' and SAR. The present paper proposed a simple model to assess and map groundwater suitability for irrigation purpose Wadi Al-Khur. Ordinary kriging method was used for preparation of thematic maps of groundwater quality parameters such as EC, Na, Cl, HCO3 and SAR. The groundwater quality index was devised to analyze the combined impact of different quality parameters on irrigation purposes. The areas for (High restriction) water quality cover 44.9% of total study area. The rest of the study area, which is about 55.1%, has water classified as (Severe restriction) quality levels. In The wet season the areas for (severe restriction) water quality cover 8.5% of total study area, and the areas for high restriction cover 87.2% of total area. The rest of the study area, which is about 4.3%, has water classified as (moderate restriction) quality levels. The values of IWQI decrease through the wet season, because of dilution of water from rainfall and decreasing the discharge which are using for irrigation.

Keywords:

Ground water , Irrigation water quality index IWQI , physico-chemical analysis , Dammam Aquifer