Water quality is essential for sustainable crop production. In this work, qualities of surface water in Dakahlia Governorate, north Nile Delta, Egypt was assessed. Main canals and drains were extracted from topographic maps. Twenty-two geo-referenced water samples were collected and analyzed. Permeability index (PI), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), magnesium adsorption ratio (MAR) and total hardness (TH) were calculated. Results indicated significant (P < 0.05) pH and EC increases in drains compared with canals. However, pH levels remained safe, while salinity showed different categories. Concentrations of Al, B, Cd, Cr, Co, Cu, Fe, Mn, Ni, V and Zn remained within the safe limit, while As, Mo and Se posed potential hazards in few localities. The PI indicated moderate quality for canals, while moderate to suitable quality for drains. The SAR indicated suitable quality for canals, while suitable and moderate quality for drains. The RSC showed safe to doubtful limit for canals, while safe to unsafe levels for drains. Canals water satisfied the standard level for MAR, except one sample, while only one drain sample was within the safe limit. The TH ranged from slightly hard to hard in canals, and from hard to very hard in drains. Integrating the above mention criteria, the water quality index (WQI) was developed. The WQI revealed that quality of canals water was excellent and good, while drains showed higher variations with ranging from excellent to very poor. The WQI and GIS provide a comprehensive vision for water condition, and should be considered in periodic monitoring of water quality. |
