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Intro > Classification > Depressions > Valley Train Pond
Valley Train Pond
Wetland Class: Depressions
Wetland SubClass: Isolated Depression
Introduction: Valley Train Pond
Landscape Setting and Hydrology
Valley train ponds are isolated wetlands associated with glacial outwash deposits (also called "valley train" deposits) in the Delta Region. They form in very shallow basins on terraces, where the basins are in fact parts of ancient braided channel systems that once carried meltwater from the continental glaciers that covered much of Missouri, Illinois, and other areas to the north. The channel systems are now shallowly buried under more recent soil deposits, but they may form extensive, interconnected subsurface networks of sandy material that collect and move shallow groundwater over large areas. Valley train ponds occur where this groundwater appears at the surface. Vegetation
Plant species in the valley train ponds are similar to those found in floodplain systems, but the characteristics of individual wetlands vary. They may include deep swamp species typical of floodplain depressions as well as species more typical of better-drained areas along mid-gradient streams. The species typical of better-drained sites, such as cottonwood, sycamore, and river birch, are usually found on deep sand bars that formed within the old channel systems. Those sand bars exist today as low sandy mounds within the swamp basins. Characteristic Plants
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| Betula nigra | river birch | | Carya aquatica | water hickory | | Carya ovata | shagbark hickory | | Diospyros virginiana | persimmon | | Fraxinus pennsylvanica | green ash | | Gleditsia aquatica | water locust | | Platanus occidentalis | sycamore | | Populus deltoides | cottonwood | | Quercus lyrata | overcup oak | | Quercus palustris | pin oak | | Quercus phellos | willow oak | | Taxodium distichum | baldcypress | | Ulmus americana | American elm | |
| Ampelopsis arborea | peppervine | | Boehmeria cylindrica | false nettle | | Brunnichia ovata | ladies’ eardrops | | Saururus cernuus | lizard's tail |
Distribution
Valley train ponds have been described on outwash deposits between the White River and Crowley's Ridge, and in the St. Francis River lowlands. Remnant examples of this wetland type may be found within some of the Wildlife Management Areas in that part of the state.
Other Isolated Depression Community TypesMountaintop Depression
Sand Pond
Sinkhole
Unconnected Alluvial Depression
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