Wetlands depressional

Prairie potholes are characterized as depressional wetlands often found in the upper Midwest including North Dakota, South Dakota, Minnesota, Iowa, and Wisconsin. Hydrology is controlled by snowmelt and rain during spring, which fills low-lying areas forming concentric circles. 

Vernal pools are small depressional wetlands that range in size from small pockets saturated with water to shallow lakes. These wetlands are found in gently sloping grassland landscapes with Mediterranean climate, such as in the West Coast. Many of these wetlands in California have been drained for development. During any given single season, these wetlands may fill and dry several times. The subsurface is either bedrock or a clay layer that helps to hold the water. 

Surface inflow and outflow are seasonally dependent on the position of wetlands on the landscape and precipitation. If the source of water is from surface inflow, the wetland would likely to be a riparian or riverine wetland. If the groundwater is the major input, the wetland would likely be a depressional wetland. 

Playas are ronnd depressional areas on the landscape fed by fresh water from rainfall. These wetlands occnr in sonthem high plains, including areas in West Texas, Oklahoma, New Mexico, Colorado, and Kansas. Some of these wetlands accumulate salts as water from underlying aquifers supplying salt percolates upward through the soil profile. These wetlands are formed seasonally and may stay flooded during the wet season and dry out during the remainder of the year. 

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See also in sourсe #XX -- [ ]

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