An Alternative Hydrograph for the Missouri River Based on the Precontrol Condition

Abstract

The Missouri River and its tributaries have been impounded and channelized, and their hydrographs, sediment and organic matter dynamics, and floodplain connectivity have been altered, adversely impacting native fish and wildlife and leaving many species with an uncertain future. Using stage and discharge data collected prior to dam construction, we defined the precontrol hydrograph and compared it with the present hydrograph and with hydrographs proposed by the U.S. Army Corps of Engineers. We offer an alternative to present operations based on the precontrol percentage of total annual discharge for each day of the year, averaged monthly. Our model may be used to restore the seasonality of flow and to minimize discharge peaks until floodplain planning and management can provide a public corridor contiguous to the river to allow reestablishment of high discharge.