Teaching Geography: Workshop 8
Global Forces / Local Impact
Workshop 8 Interactive Activity
This activity requires Shockwave.
The following activity presents GIS map data that you can manipulate in order to better understand the forces acting on the Columbia River basin.
The Columbia River basin is an area that includes the Columbia River and its branches. Dams on rivers in the basin have taken a toll on the salmon population. As young salmon, born wild or in fisheries upriver, make their way out to sea, they run the very real risk of being killed in the spinning blades of the turbines generating hydroelectricity. For adult salmon returning to spawn, the dam presents an insurmountable barrier in their journey upriver.
One of the dams in the Columbia basin is the Bonneville dam. At 77 feet high, it would be an impossible barrier for migrating salmon if it weren't for two critical features.
The first feature is rotating screens in front of the turbines. The screens deflect the young salmon up and away from the spinning blades. The second feature is fish ladders located on the sides of dams. The ladders guide the young salmon down the sides of the dam and help adults gradually make their way up and around the concrete barriers.
At the Bonneville dam, returning adult salmon making their way up the fish ladder pass a glass window, behind which sit biologists who count each mature steelhead, Chinook, and sockeye in order to monitor the salmon population.
Click BEGIN to explore the Columbia basin and the effects of dams on the salmon population using GIS.