Intro > Classification > Riverine > Low-Gradient Backwater

Low-Gradient Backwater
Wetland Class: Riverine
Wetland SubClass: Low-Gradient Riverine
Detailed Description: Low-Gradient Backwater

Introduction Low-gradient backwater wetlands occupy sites that flood frequently (1-5-year flood frequency), but flooding is primarily by slack water, rather than by the high-velocity flows that predominate in overbank flood zones. Backwater flooding usually occurs when mainstem streams are in high stages, impeding the discharge of tributaries and causing them back up onto their floodplains. This results in sediment accumulation and ponding that persists long after water levels have fallen in the stream channels. Many sites that were subject to backwater flooding in historic times are now protected by levees. Wetlands on these altered sites are classified as flats. Backwater sites that flood for long durations and are very poorly drained are usually dominated by overcup oak and water hickory. Less flooded sites are often dominated by Nuttall oak or willow oak, and the driest backwater sites may have species such as water oak, cherrybark oak, and shagbark hickory as important components in the overstory. Low-gradient backwater systems are extensive in the Delta, Coastal Plain, and Lower Arkansas River Valley. They can be visited within the Wildlife Management Areas that are located near major rivers. For more details on the Low-Gradient Backwater, click here.

Basemap adapted from ©1995 Ray Sterner

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