The depth to saturated soils will always be nearer the surface due to the capillary fringe. The major portion of the root zone is that portion of the soil profile in which more than one half of the plant roots occur. In some heavy clay soils, water may not rapidly accumulate in the hole even when the soil is saturated. If water is observed at the bottom of the hole but has not fiLLed to the 12-inch depth, examine the sides of the hole and determine the shallowest depth at which water is entering the hole. When applying this indicator, both the season of the year and preceding weather conditions must be considered .
Watermarks are most common on woody vegetation.
When several watermarks are present, the highest reflects the maximum extent of recent inundation. This indicator is most likely to be found adjacent to streams or other sources of water flow in wetlands, but also often occurs in tidal marshes. This evidence may remain for a considerable period before it is removed by precipitation or subsequent inundation. Sediment deposition on vegetation and other objects provides an. indication of the minimum inundation level. Scouring is often evident around roots of persistent vegetation.