Assessment of Water Losses in Cracked Concrete-Lined Canals

The efficiency of water delivery in irrigation canals is critical for water conservation in arid regions such as Egypt. Canal lining is a key strategy to reduce conveyance losses, particularly seepage. However, the presence of cracks in these linings can significantly reduce their effectiveness, leading to substantial water losses. This study integrates dimensional, experimental, and numerical analyses to assess seepage losses in deteriorated concrete-lined canals. A total of 54 experiments were conducted to investigate the influence of crack configuration, underlying soil characteristics, lining thickness, and canal water depth on seepage losses. The results indicate that water loss is highly sensitive to crack density—defined as the ratio of total crack surface area to the wetted surface area of the canal lining—and the hydraulic conductivity of the underlying soil. In sandy soils, bed cracks were identified as the dominant pathway for water loss, accounting for up to 75% of total water loss, compared with 29% in clay soil. Increasing the lining thickness by one-third reduced seepage losses by up to 17% in intact linings and by 7%–9% in cracked linings in sandy soils. A calibrated SEEP/W model based on the experimental data showed good agreement with the experimental results ( R 2 = 0.96 ) and successfully reproduced seepage behavior under both intact and cracked conditions. In addition, a practical assessment criterion was developed to evaluate lining conditions based on crack density and seepage in lined canals. This criterion enables systematic identification of high-risk canal reaches and provides a practical basis for prioritizing maintenance and rehabilitation interventions under limited water and financial resources in arid regions.