This lecture covers the hydrological cycle, focusing on soil water balance, including groundwater recharge, evaporation, and evapotranspiration. It explains the concepts of water content, mass balance, and steady state in soil. The lecture also delves into infiltration processes, such as capillary rise and infiltration capacity, discussing different soil types and their influence on water infiltration. Additionally, it explores steady-state water profiles and the impact of rain intensities on infiltration.