Wetland Flat

Wetland Flat

—a level or near-level wetland area that is not fed by water from a river channel, and which is typically situated on a plain or a bench. Closed elevation contours are not evident around the edge of a wetland flat.

This HGM Type was added to the Classification System in order to provide a way of classifying wetland areas on flat land (often on a coastal plain) that are not in any way connected to the drainage network (i.e. there are no river channels flowing into, out of, or through the system), and for which none of the other HGM Types seem to be appropriate.

The primary source of water for a wetland flat is precipitation, with the exception of wetland flats situated on a coastal plain where groundwater may rise to or near the ground surface. Dominant hydrodynamics in wetland flats are bidirectional vertical fluctuations, with weakly developed multidirectional horizontal water flows present in some cases. Water typically exits a wetland flat through evapotranspiration and infiltration.
Wetland flats are characterised by the dominance of vertical water movements associated with precipitation, groundwater inflow, infiltration and evapotranspiration. Horizontal water movements within these wetlands, if present, are multi-directional, due to the lack of any significant change in gradient within the wetland.

It is important not to confuse Wetlands Flats with Floodplain Flats.

Posted on February 8, 2023 09:19 PM by tonyrebelo