Natural and man-made factors in the formation of the groundwater filtration flows of the North Sinai

Abstract

Introduction: The northern part of the Sinai Peninsula is situated in an area of arid climate, and the region is characterised by an acute shortage of available water of satisfactory quality. Hydrogeological wells are almost the only source of fresh water. Further development of the region focused on the expansion of the mining activities requires a considerable increase of the need in water. Therefore, the goal of this work was to study natural and man-made factors in the formation of groundwater filtration flows that are used and can be used in the future for utility and drinking water in the northern part of the Sinai Peninsula. Methodology: The methodology of the conducted studies included the creation of a database of level regimes of Quaternary and Pre-Quaternary aquifers of the region with the observations from 151 wells. 45 aquifers characterised the hydrogeological situation for Quaternary deposits in three areas: the valley Wadi El-Arish, and in the regions of Rafah and Sheikh Zuweid. Pre-Quaternary aquifers were assessed by the sampling of 60 wells. Using SPSS, we conducted a statistical analysis to assess the measured levels of water in hydrogeological wells and, based on them and using geographic information system (GIS), we constructed hydroisogypsum and hydroisopyeses maps for each aquifer and then we prepared a generalised hydrodynamic grid of the flow to track the movement of groundwater in the North Sinai. Results and discussion: The distribution of highly powerful aquifers in Quaternary deposits is limited only by the coastal plain stretching along the Mediterranean Sea. The following principal patterns of the formation of groundwater filtration flows of the North Sinai were determined: a) the general groundwater flow moves in a sub-horizontal direction, mainly from the south to the north, in the direction of the general flow into the Mediterranean Sea, and also partially in the western and eastern directions towards the Gulf of Suez and the Gulf of Aqaba; b) on average, the hydraulic slope of the main filtration Quaternary groundwater flow from south to north is about 0.002; c) the values of statical levels of groundwater in Quaternary deposits within the coastal plain are within the range from +8.10 to –8.40 m, the negative values are typical for the sections of the operation of the production wells; d) Pre-Quaternary aquifers are deposited within the range of depths from 3.1 to 420 m. The hydraulic slopes in aquifers of Quaternary groundwater deposits are recorded in sandstone (330–410 m abs.) and are 0.003; e) there is a general tendency towards the increased mineralisation as the absolute elevation of the groundwater level decreases. Conclusions: The identified natural and man-made factors in the formation of groundwater filtration flows of the Sinai Peninsula will allow optimising the existing water supply by making the use of the Quaternary aquifer in the central part of the studied area more effective and by scientific justification of the operation of chalk aquifers excluding the increased mineralisation of groundwater. The generalised structure map of the filtration flow can be used as a basis for the development of the water supply complex within the North Sinai.