Figure 5.

Ecological-response trajectories in upstream, reservoir, and downstream reaches following dam removal. Three hypothetical trajectories are presented for each location, with rationale that explain why these alternative trajectories might emerge. The vertical line on each plot indicates the time of dam removal, and the horizontal line represents the ecological condition that existed prior to dam construction. Recovery to predam conditions are unlikely if natural flow, temperature, sediment, and nutrient regimes remain altered by other dams, if reservoir sediment contains contaminants, and if nonnative species are present. The colored sections of the trajectories indicate the short-term (orange) and long-term (yellow) ecological responses to dam removal.