**Overview** - Overland flow (surficial runoff or quick flow) occurs when excess rainwater, meltwater, or water from other sources runs off over the surface of the land. - It transports water, solutes dissolved in water, and particulates from the land to surface to waterways quickly. - Highest risk to water quality due to minimal interaction with the landscape assuming there is a contaminant source from land use. Primary pathway for soil erosion and transport. - The majority of contaminant losses from a property can occur over a small number of these events during the year. - In agricultural areas due to our land use activities, nutrient-rich sediment, and microbes are concentrated at the land surface or within the upper soil horizon making the contaminant readily available for transport if overland flow occurs. - Large contaminant load contributions to waterways occur when there has been a long time between overland flow events, particularly over the drier months. - Areas that are prone to overland flow, can deliver frequent discharges of relatively smaller contaminant load that can have just as much impact on water quality, if not more, than one large event.