Impact of irrigation modernization and high Aswan Dam inflow on Nile water system efficiency and water reuse in Egypt

Irrigation Modernization is promoted to save water in many countries, because of its proven achievement of higher efficiencies on the field level. However, the potential of irrigation modernization in achieving water savings on the basin level is contentious. Whether it also improves the Nile basin system efficiency is studied in this paper by simulating Egypt's Nile River water balance using the River Basin Simulation Model (RIBASIM-Delwaq) under regular, high, and low inflow conditions. In addition, the impacts of three irrigation modernization strategies (all canals lined, drip irrigation on all agricultural land, all canals lined and drip irrigation on all agricultural land) were investigated for the system efficiency, water reuse, and outflow to the Mediterranean. The results show that the Nile Basin system efficiency in Egypt is very high under the baseline conditions reaching up to 75.6 % due to formal and informal water reuse activities. This leaves little room for modern irrigation strategies to achieve higher system efficiencies; 75.6 %, 78.5 %, and 77.0 %, respectively. The paper concludes that modern irrigation will not increase system efficiency or the outflow to the Mediterranean significantly, however, it will reduce official and unofficial water reuse by allowing farmers to receive more water from canals instead of drains and shallow groundwater. • Nile system efficiency is very high (75.6 %) under baseline conditions. • Irrigation Modernization (IM) doesn’t increase Nile system efficiency significantly. • IM doesn’t change Outflow to the Mediterranean significantly. • IM decreases water reuse on the command area and system levels. • Economic and Environmental Impacts are key in IM comprehensive assessment.