Dunne overland flow

Dunne overland flow is a mechanism that generates surface runoff. It occurs when the water table is shallow or an impeding layer is present near the surface, and precipitation rates are lower than the soil's saturated hydraulic conductivity. In this scenario, surface saturation happens because the water table rises. Ponding and subsequent overland flow occur when the soil can no longer store additional moisture. This process is more common in areas near channels where water tables are shallowest. This differs from Horton overland flow, which happens when rainfall exceeds the soil's saturated hydraulic conductivity, leading to saturation from the surface downward.1