This system includes shallow freshwater water bodies found in small depressions gouged into basalt by Pleistocene floods. These are found throughout channeled scablands of the Columbia Plateau in Washington's eastern Columbia River Gorge. They typically occupy the bottom of a basalt cliff (1-20+ m tall) lined circular or linear depression. Characteristic shoreline vegetation lining the aquatic environment is an emergent marsh that includes species of Scirpus and/or Schoenoplectus, Typha, Juncus, Potamogeton, Polygonum, Nuphar, and Phalaris. This system may also include areas of relatively deep water with floating-leaved plants (Lemna, Potamogeton, and Brasenia). Woody plants, including Populus tremuloides, Salix exigua, Crataegus douglasii, or Rosa woodsii, are present adjacent to more northerly potholes. Ponds are within Artemisia shrub-steppe and Pinus ponderosa savanna or woodland. The wetland vegetation occupies a narrow zone (0.5-10 m) between open water and upland vegetation.
Information Source: http://www.natureserve.org/explorer/