Hidden Risks to Sustainable Operation of Water Systems: Suffosion Process Triggered by Pipe Leakage

Abstract

Failures and leakages in water distribution pipelines affect the sustainable operation of water supply systems. While water losses caused by leaks are widely recognized, their impact on soil stability and internal erosion processes remains insufficiently investigated. This study examines water flow velocity distributions in soil around leaking water pipes regarding suffosion risk. Numerical simulations were performed using the FEFLOW software for four scenarios combining two pipe diameters and two internal pressure levels. Each scenario assumed circumferential leakage with continuous water outflow into the surrounding soil. The numerical model was validated through field experiments conducted on four experimental setups. The simulation results showed that flow velocities near the pipe exceeded critical values in all scenarios, indicating a risk of suffosion. Although hydraulic pressure and leakage area significantly affected local flow velocities, their influence on the extent of the potential suffosion zone was negligible. In all cases, the zone where critical velocities were exceeded extended more than 1.5 m from the leakage location. The results highlight the importance of considering suffosion risk in the operation and risk assessment of sustainable water supply systems. They also indicate that this hazard should be taken into account during the design stage, particularly when selecting pipeline routes and assessing ground conditions.