Assiut J. Agric. Sci., (48) No. (4) 2017 (216-228) ISSN: 1110-0486 Website: http://www.aun.edu.eg/faculty_agriculture E-mail: [email protected] Salinity Status of Groundwater in El-, New Valley Governorate, Abdelrazek, M.1; K.K. Attia1; M.M.M. Ahmed2 and S.A. Mohamed2 1Department of Soil and Water, Faculty of Agriculture, Assiut University, Assiut, Egypt. 2Soil, Water and Environment Res. Ins. Agric. Res. Center, , Egypt. Received on: 17/5/2017 Accepted for publication on: 21/5/2017

Abstract This investigation aims to evaluate the groundwater quality of El-Dakhla oasis, New Valley governorate, Egypt and assess its suitability for irrigation. About 144 groundwater samples were collected from wells distributed in eleven transects that represent the study area. The obtained results indicated that 63 samples were under the C1S1 indicating category low sodium and low salinity hazards. Meanwhile, 72 samples in the C2S1 category showing low sodium and medium salinity hazards and 9 samples exhibited a C3S1 type resulting in low so- dium and high salinity hazards. According to Wilcox diagram, 93.75% of the water samples had an excel- lent quality for irrigation and 4.86% of them were considered as a permissible class. The results also revealed that 49.31% of these samples gave positive chloro-alkaline index (CAI) values. However, the remaining samples (50.69%) showed negative CAI. With respect of the corrosivity ratio (CR), 140 groundwater samples (97.22%) were safe to transport in mineral pipes whereas only 4 samples (2.78%) were corrosive in nature and need non-corrosive pipe to transport and lift these groundwaters.

Keywords: El-Dakhla oasis, groundwater, salinity (ECw), sodium adsorption ration (SAR)

Introduction spatial variations of its chemistry The groundwater is the only re- (Soltan, 1999; Kumar et al. 2006) newable water resource in El-Dakhla flow and salt content as well as hu- Oasis, New Valley, Egypt. Therefore, man activities (Karanth, 1997; Al- groundwater resource assessment and Shaibani, 2008). sustainability considerations are most Therefore, the aim of this study important in this region where water is to evaluate the groundwater quality is common of critical economical and of El-Dakhla oasis and assess its suit- social significance. About 85% of ability for irrigation. these waters are used in agriculture Materials and Methods (MWRI, 2014). This study was conducted on The quality of groundwater is El-Dakhla Oasis, New Valley Gover- considered as important as its quan- norate, Egypt, which bounded by tity. So, the chemical analysis of wa- longitudes of 28° 30` to 29° 30` E and ter is very important. Groundwater latitudes of 25° 11` to 26° 00` N. It quality is affected by the seasonal and covers an area of about 100 km2.

Abdelrazek, et al., 2017 http://ajas.js.iknito.com/ About 144 groundwater samples were ions were carried out in the Labora- collected from wells distributed in tory of Agricultural Research Station, eleven transects representing the El-Kharga, New Valley, Egypt. So- study area (Fig., 1) to assess their dium and potassium concentrations quality and suitability for irrigation. were determined using a flame pho- Each sample was situated using the tometer while calcium and magne- Global Position System (GPS). The sium concentrations were determined distance between each two conse- by EDTA titration. Chloride was es- quent transects was 4.5 to 6 km. timated using silver nitrate titration The electrical conductivity of and bicarbonate was measured with each water samples (ECw) was meas- acid-base titration. Sulphate was de- ured in-situ using a portable EC me- termined using a spectrophotometer ter. The chemical analyses for major (Jackson, 1973).

Fig. 1. A location map of groundwater samples

Irrigation water quality parame- and corrosivity ratio (CR) were calcu- ters such as sodium adsorption ratio lated using establi