干旱区生态环境知识资源中心

Assessing the vulnerability of groundwater is the first step toward careful management of water resources to avoid or, at least, to minimize impacts on agriculture. The objective of this study was to propose a simple method to assess the groundwater quality and to map its spatial variation in terms of suitability for irrigation in the Darb El-Arbaein area, Southwestern Desert, Egypt. Thirty-six surveyed wells were used to assess and map the groundwater quality. For calculating the Water Quality Index (WQI), a total of 20 (13 chemical, two physical, and five calculated) parameters were considered e. g., EC, pH, Cl, SAR, B, Zn, iron, Mn, Pb and Cd. The results of analyses were used to propose a water quality model. The different water quality maps were produced using GIS software. The results show that three water samples fall into the moderate WQI. Most of the samples (26) fall into the unsuitable WQI category. Seven samples fall into the suitable WQI category. Groundwater samples that fall into the low salinity hazard class and high WQI can be used for irrigation of most crops and the majority of soils. The WQI for the samples ranges from 47.9 to 88.6. The WQI distribution maps delineating an area of 266.66 ha are suitable for irrigation in villages (3,4) and areas of 382.35 ha are moderately suitability for villages (1,2). Since the final map shows the spatial distribution of irrigation water quality in the area, it is now much easier for a decision maker to assess the water quality for irrigation and to locate the most suitable site for drilling wells. The present study demonstrates high efficiency for GIS to analyze complex spatial data and groundwater quality mapping.