|Rehabilitation of a Severed Meander Bendway: Effects of Flow Augmentation - Abstract
Seasonal flooding of riverine backwaters is important for maintaining diverse aquatic habitats. Anthropogenic impacts have reduced frequency and duration of such flooding at many sites. This study, conducted in a 2.5-km-long severed meander bendway adjacent to the Coldwater River in Tunica County, Mississippi, compared water quality during a late summer 30-day flow augmentation period to 28-day pre-treatment and 26-day post-treatment periods. Flow augmentation (simulating backwater flooding) consisted of pumping 0.35 cubic meters per second from the main channel of the river into the upstream end of the severed bend. In-situ parameters (temperature, pH, dissolved oxygen, conductivity) were measured every 30 min at two of three sites. Solids (total dissolved and suspended) and nutrients (phosphorus and nitrogen) were measured at all three sites and inflow every 3-5 days. Decreases in amplitude of diel cycles in temperature, dissolved oxygen, and pH were observed with augmentation. Changes in patterns of solids (dissolved and suspended) and nutrients (nitrates, nitrites ad soluble orthophosphates) were also associated with induced flow. Total phosphorus and ammonium patterns were more complex due to utilization by autotrophs (measured as chlorophyll a). Flow augmentation stabilized water quality and improved habitat for aquatic biota.