Lake Hydraulic Residence Time as Hydrologic Management Guidance for Sustaining Lake Development (Case Study: Lake Edku, Egypt)

Lake Edku is one of the northern Nile Delta lakes in Egypt. It suffers from a high level of eutrophication. Lake Edku suffers from pollution from a variety of sources, including municipal and agricultural waste. This study presents a simulated model for a hydrology system that provides a challenge in predicting hydraulic residence time or how water contaminants circulate over the time. Hydraulic residence time is realized as a measure of how rapidly water quality will be affected by changes in pollutant loadings. A hydrological model was created to predict the hydraulic residence time for Edku Lake using a modular three-dimensional finite-difference groundwater flow model called “MODFLOW”. The model revealed that the accurate hydraulic residence time for Lake Edku is 14, 25, 20, and 10 days for autumn, winter, spring, and summer correspondingly, with a 17.25-day yearly average. However, this study presents many challenges in understanding how hydraulic residence time is determined by considering the interaction between surface water and subsurface water. Lake hydraulic residence time calculations are considered a useful water quality management tool in preparing the proceedings and solution scenarios that in turn will contribute to lake restoration efforts.