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Scope/Content: Abstract: Glines Canyon Dam impounds about 8.5 m m3 of mixed grain size sediment in the Lake Mills delta. It is hypothesized that, up to a certain point, an increase in the magnitude and rate of dam removal (base level lowering) will result in increased volumes and rates of delta erosion and progradation into the reservoir. Beyond this point, though, it is unclear whether these volumes and rates will continue to increase at the same rate or whether negative feedback mechanisms will act to reduce the rates, and maybe even the total volumes, at which sediment is prograded. Negative feedback may occur if sediment is prograded progressively more quickly and further into the reservoir in the early stages of response to progressively larger increments of dam removal, thus increasing the ?y component of bed slope change more quickly than the ?x component decreases due to the upstream migration of incision. If so, the rate at which bed slope decreases may increase significantly, thus decreasing the flow's ability to erode sediment and causing more rapid system stabilization. Further, if progressively larger increments of dam removal cause more lateral channel movement to occur in the early stages of adjustment, this might recruit more gravel from the delta terrace deposits, thus enabling more of the channel to armor more rapidly and more completely than with smaller increments of removal. Finally, the armoring process will be exacerbated if the rate at which bed slope decreases does increase significantly, since a rapid decrease in slope will cause a rapid decrease in boundary shear stress and thus decrease the likelihood of gravel movement. A series of dam removal experiments was performed in a scaled physical model, which was built and operated at the St. Anthony Falls Laboratory, in order to address these research hypotheses.