Framework / Assessment USDI Indicators of Rangeland Health (2000) Summary Flow patterns are the path that water takes (i.e., accumulates) as it moves across the soil surface during overland flow. Overland flow will occur during rainstorms or snowmelt when a surface crust impedes water infiltration, or the infiltration capacity is exceeded. These patterns are generally evidenced by litter, soil or gravel redistribution, or pedestalling of vegetation or stones that break the flow of water. Interrill erosion caused by overland flow has been identified as the dominant sediment transport mechanism on rangelands.