3.1.5. Drains discharging to Lake MariutAll drains discharging to Lake Mariut showed no significant trends in water quality over time. A high P value(P = 0.267, 0.137 and 0.474 for El Umum Drain, EL Qalaa Drain and West Nubaria Drain, respectively; Table 3)suggests that year of measurement is having a small impact on water quality of those drains. In addition, temporalchanges in year of measurement can explain only 13.40, 22.80 and 6.60% of the temporal variability observed in theWQI respectively (Table 3).WQI of EL Qalaa Drain is rated as poor; this has been reported in by Shreadah et al., 2014. On the other hand,WQI of El Umum Drain fluctuated from marginal to fair in. The best drain that has high score of water quality is WestNubaria Drain which, WQI can be mostly rated as fair (Fig. 8).