Ex post impact assessment of Marwa rehabilitation on irrigation performance under water scarcity in Egypt

Egypt faces growing water scarcity due to population pressure and inefficient on-farm irrigation practices. Improving on-farm water-use efficiency is essential for sustaining agricultural productivity. This study assesses the long-term impacts of rehabilitating on-farm ditches (Marwas) serving 3-5 acre farms in the Hafez El Sharkeya Canal command area, Menia Governorate, five years after implementation. A combined technical and socio-economic assessment was conducted using hydraulic measurements, geometric surveys, and interviews with 40 farmers (20 beneficiaries and 20 non-beneficiaries). Results showed that rehabilitated Marwas with uniform, prismatic cross-sections facilitated better water conveyance and consistently met peak summer demand, while unimproved ones suffered from water losses and weed proliferation. Application efficiency for wheat increased from 50-60% in unimproved to 63-89% in rehabilitated Marwas. Water use efficiency increased from 0.59-0.69 in unimproved fields to 0.72-0.87 in rehabilitated systems. Water productivity for wheat was higher in rehabilitated Marwas (1.75 kg/m³) compared to unimproved ones (0.93 kg/m³). More than 80% of surveyed farmers preferred rehabilitated Marwas, citing reduced irrigation time, lower maintenance costs, and improved land utilization. The findings indicate that Marwas rehabilitation is associated with improvements in hydraulic performance, equity in water distribution, and greater farmer satisfaction with water delivery. The results offer relevant insights for efforts aimed at improving water-use performance in similar smallholder irrigation systems. However, broader multi-season and multi-location studies remain necessary before drawing generalized conclusions at the national scale.