Spatiotemporal Hydrochemical Evaluation and Quality Assessment of Drainage Water Compared to Canal Surface Water in the Middle Nile Delta, Egypt

The aim of the present chapter is to assess the spatiotemporal variability in the hydrochemistry of the main surface water streams (drains and canals) in the middle Nile Delta and their suitability for drinking, irrigation, and fish farming usage based on the hydrochemical data. To perform this target, physicochemical parameters were measured during winter and summer seasons (2016) in water samples collected from two main irrigation canals (Mit-yazed canal, four stations, and Qudaba canal, five stations) and two main drains (Janag drain, four stations, and El-Gharbia main drain, five stations). These stations were arranged from south to north along the flow system of each stream. The field-measured salinity and the analyzed major ions showed an obvious increase along the flow path from south to north. Trace element spatial distribution showed different trends depending on the source of water, the intersection of the studied stream with another, the local urban conditions, as well as the effect of the seawater invasion. The sample hydrochemical types and the cluster analysis reveal an obvious temporal difference between winter and summer seasons for each water body. The water suitability for different uses is better in summer than in winter due to the low water input to the streams during winter. The water of the irrigation canals was suitable for drinking, irrigation, and fish farming either in winter or in summer. Compared to water quality in irrigation canals, drains’ water quality is of medium quality according to IWQ index (except sample 5 of El-Gharbia main drain which is of low quality) and plotted in the unsuitable and high-salinity fields in Wilcox and USSL classification diagrams, respectively. P, N, Mn, Zn, and Fe were above the permissible limits in drain water for fish farm irrigation.