Upper Midwest Environmental Sciences Center
Cumulative impacts of river engineering, Mississippi and Lower Missouri rivers
Pinter, N., A. A. Jemberie, J. W. F. Remo, R. A. Heine, B. S. Ickes. 2010 Cumulative impacts of river engineering, Mississippi and Lower Missouri rivers. River Res. Applic. 26: 546–571.
The goal of this study was to construct a large, data-rich model to test hydrological responses to engineering modifications on over 3200 km of the Mississippi and Lower Missouri Rivers. We compiled model explanatory variables from a geospatial database quantifying construction of all bridges, wing dikes, bendway weirs, levees, artificial meander cutoffs, channel constriction and navigational dams over the past 100–150 years. Response variables were derived from 68 rated and un-rated hydrologic stations in the study area, with responses analysed across a range of discharges from within-channel flows up to moderate floods. Correlation analysis, multiple linear regression and stepwise regression analyses document strong and consistent responses to construction history, both in individual reach-scale models and systemwide. Meander cutoffs are associated with degradation and acceleration of flow that has reduced stages across the full discharge range. Navigational dams on the Upper Mississippi River increased low-flow stages and flood levels to a lesser extent, with little or no post-dam change. One of the strongest signals was the hydrologic response to wing-dike construction, which resulted in large back-water increases in stage upstream of wing dikes and mixed effects downstream, including the overlapping effects of incision and velocity losses. Levees were associated with local flow concentration, overbank storage loss and floodplain conveyance loss depending on reach-scale conditions. The results presented here (1) quantify incremental and cumulative hydrologic responses to a range of engineering activities and (2) provide an empirical tool for verifying and assessing hydraulic and other models of river-system change. Copyright © 2009 John Wiley & Sons, Ltd.