Improving water resources management efficiency under arid regions conditions based on simulation model technique

Water scarcity is a key obstacle to sustainable development, particularly in arid countries like Egypt, where limited freshwater resources pose challenges to agricultural activities. This study evaluates water management plans applied to the Western Nile Delta, using the so-called SIWARE (SImulation of Water management of Arab Republic of Egypt) model, to analyze irrigation scenarios under varying freshwater availability. The model utilizes diverse input datasets, including daily meteorological data (rainfall, temperature, solar radiation, wind speed, and humidity), irrigation schedules, crop patterns, soil properties, and water salinity levels. It explores the impacts of reusing drainage water on soil salinity, crop yield, and sustainable irrigation practices. The results provide useful information on the potential spatial distribution of drainage water reuse and its associated salinity risks. About 835.9 million cubic meters/year (MCM/year) of drainage water were reused unofficially by farmers, with 86% classified as medium salinity (0.75–2 dS/m). Under the scenario of 30% reduced availability of fresh water, unofficial reuse decreased to 802.2 MCM/year. Average soil salinity was 2.55 dS/m, with a range from 1 to 7.57 dS/m; higher salinity levels were found in the northern and western coastal areas. About 533,000 feddans were mapped as having a moderate degree of salinity (2–4 dS/m). Drainage water from the Edko and Umom drains has substantial reuse for crop-tolerant salinity up to 2,000 ppm. Nearly all water from the Edko drain meets reuse standards, and 60% of Umom drainage water is suitable. Under reduced freshwater scenarios, reusability remained for the Edko drain but reusable water from the Umom drain declined to 48%. This study re-emphasizes the need to integrate drainage water reuse into water resource management plans. Enhanced adaptation tactics and irrigation techniques are crucial to address salt issues and water scarcity, hence maintaining the long-term sustainability of agriculture in the Western Nile Delta.