From 1850 to 1950 open water decreased from . From 1950 to 2005 the amount of open water decreased to . When the Atchafalaya Basin flow plan was implemented (1950–1974), 30 percent of the total Atchafalaya River flow was designated to be directed off the main channel, 15 percent to the east and 15 percent to the west side. As a result of the Atchafalaya River channel bed incision, in the early 21st century the flow distribution is 13 percent of the total flow, with a flow distribution of 7 percent to the east side and 6 percent to the west side as reported by the USGS. This decrease in flow across the floodplain, in conjunction with high organic deposition from trees and floating vegetation and high water temperature, has resulted in large areas of low-dissolved oxygen water. Where once the water was black (1850), the water became brown (1927). Where the water was formerly brown (1927), it is now black (2009).