IOSR Journal of Applied Geology and Geophysics (IOSR-JAGG) e-ISSN: 2321–0990, p-ISSN: 2321–0982.Volume 7, Issue 6 Ser. II (Nov. – Dec. 2019), PP 63-72 www.iosrjournals.org DOI: 10.9790/0990-0706026372 www.iosrjournals.org 63 | Page Hydrochemical Modeling and Assessment of Quaternary Aquifer in the Nile Valley, Qena, Egypt Abdel Mawgoud Mohammed 1 , Raafat M. El Attar 1 1 (Geology Department, Faculty of Science, South Valley University, 83523 Qena, Egypt) Correspondingauthor. (Raafat M. El Attar). __________________________________________________________________________________________ Abstract: The study was conducted on the Quaternary Aquifer in the Nile Valley of Qena area in Egypt. Sixty−six groundwater samples were collected from the study area along with two surface water samples. The hydrochemical analyses were carried out for the collected samples comprising the major ions and heavy metals. The application of the software package (PHREEQC for windows version 2.8.00) is the main target in this study. PHREEQC was used to perform a variety of aqueous geochemical calculations including the saturation indices (SI) of the major mineral phases, testing of water corrosivity and to apply water mixing models. The Saturation Indices show a supersaturated with respect to the main carbonate minerals (calcite, aragonite and dolomite) nearly in all the samples. Calcite, aragonite, and dolomite represent the major sediments that built up the geology of the study area (the Limestone Plateau). The investigated groundwater samples varies from moderately corrosive (1.5%), mild corrosion (7.57%), faint coating (22.72%), and mild scale forming (68.18%). The mixing models were conducted between water from different sources as a proposed solution for lowering the chemical content especially nitrate levels in the highly contaminated wells to acceptable limits. As indicated from the results of mixing, mixing can be used as an effective water treatment method. Keywords: Quaternary Aquifer, hydrochemical, corrosivity, mixing models, contaminated wells. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 09-12-2019 Date of Acceptance: 24-12-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction The steady increase of the population and the rapid expansion of the national economy in Egypt in the last few years has become a progressive vital problem which represents the greater challenge to Egypt's future and compelled the Egyptian authorities for establishment of new settlements and land reclamation projects. As water is vital for all of us and we depend on its good quality and quantity for drinking, reclamation, use in industry and growing crops, it is necessary for the development of water supplies to satisfy the demand of agricultural municipal and industrial requirements. Even in Egypt there is a continuous demand for more water for reclamation of new land to be added to the existing cultivated acreage. As Egypt is essentially a desert land (about 97%), and in the desert areas of Egypt the surface water resources are generally very limited, therefore, groundwater resources constitute a cornerstone for any development project. The study of groundwater in the Eastern Desert is of a great important since the water resources are rare and thus constitute a major obstacle for both living and projects. Groundwater serves only 7% of water demand in Egypt [1]. In fact, groundwater is more desirable than surface water for many reasons including the absence of pathogenic organisms, color and turbidity, its constant chemical composition with no radiochemical nor biological contaminations and its great storage. The contamination of groundwater cannot be polluted easily as compared with surface water because it is protected naturally, so it is more reliable [2] . Unfortunately, the continues development of the human societies as well as the land reclamation and agricultural projects lead to the water and soil pollution by the septic systems, waste water disposals, fertilizers and pesticides by both point and non point source of pollution. The selected area for the present investigation comprises a part of the Eastern Desert which have the two parts (the cultivated area and the reclaimed area) (Figure 1). Both the quantity and the quality had been considered before evaluating the groundwater resources. The study are at Qena represents an area of most extensive groundwater resources in the Upper Egypt, where considerable amounts of groundwater have been exploited and used in the reclamation. Groundwater is very important source for drinking, irrigation and domestic uses in the study area for both rural and urban and varies from the first to second source of water along with the River Nile. Tube wells have also been the only source of irrigation water in small-scale reclamation schemes. In most cases wells are constructed on farmer’s initiatives. Individual farmers or groups of farmers