Sediment oxygen demand and its effect on dissolved oxygen in a cutoff meander of the Kaskaskia River

This study was designed to assess the relationship of sediment oxygen demand and dissolved oxygen in a cutoff meander of the Kaskaskia River. The results of the study should be useful to agencies such as Departments of Conservation, Corps of Engineers and the Environmental Protection Agency when assessing the impact of stream channelization on cutoff meanders of channelized streams. Cross-sectional profiles were used to determine area and total water volume in the meander. When stagnant or no-flow conditions prevailed, anoxic conditions created by sediment oxygen demand were observed in a significant part of the water in the meander. When no-flow conditions prevailed during summer months, as much as 25% of the water in the meander became anoxic while 65% fell below 5.0 mg/l. Sediment oxygen demand rates were more closely related to temperature than to sediment consistency or benthic macroinvertebrate numbers. Ambient sediment oxygen demand measured during the summer was almost three times greater than demand measured during the fall. While sediment oxygen demand in the channelized portion of the river was higher than in some stations in the meander, reaeration resulting from flowing water in the channel was sufficient to prevent anoxic conditions from developing.U.S. Department of the InteriorU.S. Geological SurveyOpe