We did not resolve anything in that meeting, but the discussion left me wondering to what extent the salmon problem could be attributed to any one human activity. Dam breaching, the removal of the four Lower Snake River dams, has been a controversial proposal in the region for several years. It was initially proposed by environmental groups, but various federal agencies have become involved in scientific studies about the impacts of dams and possible ways of mitigating those impacts. As a science fellow, I felt I could give the senator an overview of the science used in making policy about the dams. As a geologist, I grew concerned that the debates on fish population models were obscuring some important issues.
Geologists are familiar with the idea that dams store sediment and cause changes in river channels.
But government studies of the dams contained little discussion of what would happen to the stored sediment or the river channel if the dams were breached. Nor did they recognize that, ironically, breaching the dams could initially have an adverse effect on the salmon as the river system adjusted to a new equilibrium. Thus the issue that would probably be the first to catch a geologist's attention is nowhere on the radar screen in the policy debate. I kept returning to the lobbyists' graph. The decline in salmon populations correlates in time not only to dam construction, but also to other major changes in the Pacific Northwest.