Assessing the Agricultural Drainage Water with Water Quality Indices in the El-Salam Canal Mega Project, Egypt

The water quality index (WQI) is considered one of the most promising methods for the classification of water quality (WQ), which also contributes to water resource management. This study adopted the irrigation WQ index (IWQI) and an analogous index based on a fuzzy logic approach, namely, the fuzzy logic water reuse index (FWRI) to assess the water quality in the El-Salam canal project in Egypt where agriculture drainage water (ADW) is expected to be reused for irrigation. Simulated WQ data using a one-dimensional hydrodynamic model indicated that the WQ deteriorated towards the downstream of the canal due to the polluted water discharged from canal feeders (e.g., the El-Serw and Bahr Hadous drains). The comparison of the FWRI and IWQI indices showed that the FWRI was more sensitive to variations in the WQ parameters compared to the IWQI. In contrast, the Z-test indicated that the indices have different statistical properties. Moreover, a chi-square test (X2) illustrated that the FWRI and IWQI values can both reasonably explain the current situation. However, the FWRI was more relevant to the official classification than the IWQI. Overall, the FWRI proved its capability and accuracy for the assessment of water quality in the El-Salam canal.