UNDERSTANDING AND PREDICTING THE IMPACT OF AGRICULTURE ON THE ENVIRONMENTAL INTEGRITY OF MANAGED WATERSHEDS
Location: Water Quality and Ecology Research
Title: Effects of artificial flooding on water quality of a floodplain backwater
Submitted to: River Research and Applications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2011
Publication Date: December 19, 2012
Citation: Lizotte Jr, R.E., Shields Jr, F.D., Knight, S.S., Cooper, C.M., Testa III, S., Bryant, C.T. 2012. Effects of artificial flooding on water quality of a floodplain backwater. River Research and Applications. 28:1644-1657. DOI: 10.1002/44a.1553.
Interpretive Summary: We measured the effects of a late summer artificial flooding event on water quality in a river floodplain backwater (severed meander bend) along the Coldwater River in Tunica, County, Mississippi, USA. Flooding affected water temperature, oxygen, acidity, nutrients, and algae. Flooding stabilized and improved overall water quality for aquatic plants and animals and can be used to restore river floodplain backwater habitats. These findings are of interest to land managers and scientists interested in riverine aquatic ecosystem restoration and management.
Seasonal flooding of riverine backwaters is important in maintaining diverse aquatic habitats, but anthropogenic impacts have reduced the frequency and duration of such flooding. This study, conducted in a 2.5 km-long shallow floodplain severed meander backwater adjacent to the Coldwater River in Tunica County, Mississippi, USA, compared water quality during a late summer 30-day artificial flooding period to 28-day pre-flood and 26-day post-flood periods. Flooding was simulated by pumping 0.22 to 0.35 m3 s-1 from the river into the upstream portion of the backwater. In-situ parameters (temperature, pH, dissolved oxygen, conductivity, and fluorescent chlorophyll) were measured every 30 min at one site within the backwater. Solids (dissolved and suspended) and nutrients (phosphorus and nitrogen) were measured at three sites in the backwater and in the river every three to five days. Decreases in the amplitude of temperature, dissolved oxygen and pH diel cycles within the backwater were observed during flooding. Changes in patterns of solids and nutrients were also associated with flooding. Complex patterns in phosphorus and nitrogen emerged due to utilization by autotrophs (measured as chlorophyll) and seasonal changes. Artificial flooding in a shallow floodplain water body stabilized and improved water quality for aquatic biota and is a viable method for habitat rehabilitation in these systems.