The new Funan Techo Canal in Cambodia’s low-lying Mekong Delta faces significant salinity intrusion,threatening agricultural irrigation on both banks of the river.It is necessary to assess the extent and distribution of saltwater intrusion of the newly constructed canal and propose effective countermeasures.The three-dimensional hydrodynamic-salinity model of Funan Techo Canal is built using MIKE3 to systematically analyze saltwater intrusion patterns both without mitigation and with the operation of a ship lock.The results indicate that salinity intrusion is primarily driven by tidal dynamics and density gradients.The maximum intrusion distance of the 1 psu isohaline exhibits an inverse logarithmic relationship with the upstream freshwater discharge.At a low inflow Q=1 m3 /s,the 1 psu saltwater intrudes up to 25.2 km,this distance is significantly reduced to 12.5 km when the inflow increases to Q=20 m3 /s.The implementation of a ship lock can control upstream water levels and follow specific gate operation sequences to block seawater effectively.It markedly suppresses the intrusion distance and reduces salinity concentrations.After six months of ship lock operation,the 1 psu intrusion distance is limited to just 6.6 km,and the salinity at the lock head decreases from 27 psu to 5.5 psu.Therefore,the ship lock is identified as the key engineering measure for salinity control.Its operation,combined with upstream water level and flow regulation,can synergistically ensure the security of freshwater resources along the canal.