Cooperative Fish and Wildlife Research Units Program: Missouri
Education, Research and Technical Assistance for Managing Our Natural Resources

Stream flow is a critical, yet complex driver of ecological processes in streams. Numerous studies have attempted to identify metrics that best represent hydrological alteration caused by dams, diversions, withdrawals, land use, and other anthropogenic activities (e.g., Poff et al. 1997; Olden and Poff 2003). However, there is still no consensus on how these hydrologic indices are linked to ecological processes and, in particular, fishes. In addition, the science related to ecological/environmental flows is rapidly evolving and many studies/case histories may not be published or are currently being conducted. Although these results may be preliminary, the knowledge gained from even these preliminary studies will aid in the management of stream flows in Missouri. Recent research in Missouri has developed tools useful in determining ecological flows. Kennen et al. (2009) classified Missouri streams into five stream types, and also developed the Missouri Hydrologic Assessment Tool (MOHAT) which can be used to establish a hydrologic baseline and help aid in the development of ecological flow standards. This work was subsequently tested and refined by Tracy-Smith et al. (Unpublished report), who made recommendations for improving the MOHAT, and identifying a period of record (1955-1975) that could potentially be used as baseline for future comparisons. However, there are still substantial improvements that need to be made to MOHAT, and to our understanding of how hydrological alteration is linked to biological integrity of streams.