Enhancing Water Quality and Agricultural Resilience through Riverbank Filtration: A Case Study from the Nile River, Egypt 

  Projected climate changes in arid and semi-arid regions, such as reduced aquifer recharge capacity and altered riverine hydrography, pose significant challenges to water supply, particularly in the Nile River basin in Egypt. Riverbank Filtration (RBF) offers a sustainable, cost-effective water treatment technology that enhances the quality of water abstracted from polluted rivers. By installing abstraction wells along riverbanks, RBF supports agricultural resilience and climate adaptation by providing a stable and reliable water source during extreme events. This study evaluates a full-scale RBF site in Akhmim City, consisting of four vertical wells located 50 meters from the Nile River bank. Samples were collected from both the RBF wells and the Nile River during a period of extreme precipitation in November 2016, which significantly affected the river’s water quality. Key parameters analyzed included turbidity, dissolved oxygen, total suspended solids, total organic carbon, pH, electrical conductivity, bacterial counts, and coliform levels. Results showed that while Nile River turbidity ranged from 5–25 NTU, with potential hundred-fold increases during flash floods, RBF wells consistently maintained turbidity below 5 NTU. Similarly, bacterial counts in Nile water exceeded 55,000 CFU/100 mL during the event, compared to less than 2,100 CFU/100 mL in RBF water. The pH of Nile water was measured at 8.6, compared to 7.5 for RBF filtrate. These findings indicate that RBF significantly improves both physical and microbiological water quality, meeting national irrigation water standards. Moreover, RBF not only enhanced the quality of ambient groundwater but also effectively purified Nile water, making it a viable alternative to conventional surface water treatment plants. This study highlights the cost-effectiveness and reliability of RBF as a treatment solution in the Nile Valley, offering an adaptable and sustainable approach to mitigating the impacts of climate change while supporting agriculture and water security.Keywords: Climate change, Arid and semi-arid regions, Nile River, Riverbank filtration, Aquifer recharge, Water quality, sustainable water treatment.