Groundwater Quality Assessment in Siwa Oasis, Egypt, Using Different Indicators and GIS

Abstract

Groundwater plays a pivotal role as a natural resource for human existence due to its ability to provide a consistent water supply to the populace and its status as one of the primary sources of irrigation for enhancing agricultural productivity. The Siwa Oasis in Egypt is a popular tourist destination with agricultural and economic significance. This study integrates the geographic information system (GIS) technique with various hydrochemical indicators and statistical factor analysis to assess the groundwater quality for irrigation purposes. Thirty groundwater samples were sourced from the oasis's three main water resources: wells, springs, and lakes. The analysis took place at the Water and Soil Lab Unit of the Desert Research Centre in Cairo, Egypt, adhering to the standard protocols laid out by the American Society for Testing and Materials and the accepted techniques of the American Public Health Association (APHA). The suitability of groundwater for irrigation was assessed using FAO recommendations, focusing on parameters that proved more effective in the Siwa Oasis context. These parameters included the percentage of sodium (Na %), sodium absorption rate (SAR), soil water permeability index (PI), and potential salinity (PS). According to the findings, the majority of wells and some springs are suitable for irrigating crops that can withstand high salinity levels. Lakes, on the other hand, were unsuitable for irrigation due to their extreme salinity and the presence of more dissolved solids than other water sources; these lakes serve as drainage for other resources within the oasis.