A thorough understanding of fine particles clogging mechanisms is one of the critical issues during artificial recharge. This study was conducted to examine the effects of solution ionic strength (IS) and flow velocity on colloid transport and deposition in saturated porous media. Column transport experiments were carried out with different flow rate at various solution IS. These experiments were designed to obtain the long-term breakthrough curves (BTCs) in order to determine parameters by Hydrus-1D modeling. The results indicated that the BTCs were rising with increasing flow rate at given solution IS during attachment stage and values of key parameters. The results showed that these parameter values were controlled by the effects of solution IS at given flow velocity conditions and the parameter value increases with the increase of ionic strength. The effect of flow velocity was more significant for the chemical conditions when IS equaled to 30 and 50 mmol·L-1. An explanation for these observations was obtained from extended interaction energy calculations that considered chemical heterogeneity on the sand surface. Interaction energy calculation showed that the size of the energy barrier to attachment in the primary minimum (ΦT) reduced with increasing IS. The enhanced residence time available at low flow velocity allowed the bacteria to gain enough thermal energy to overcome the strength by realizing a primary minimum attachment. In addition

the hydrodynamic torques were small at microscopic roughness locations and grain-grain contacts. Therefore

a subsequent increase in flow velocity followed by retention phase had a negligible effect on the particles deposited at these favorable attachment locations. Hence

this study provided a very systematic experimental and theoretical evidence that the colloidal retention depended on the chemical feature and the flow velocity. On the whole

the migration and retention behavior of colloidal particles during the recharge process was mainly controlled by the ionic strength. However

the hydrodynamic characteristics interrupted the control of ionic strength. During the artificial recharge engineering

the two factors should be considered together to against the clogging.