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Introduction How Rivers Run Stories Value Of A River What We Can Do
Connections of a River - Connectivity
Longitudinal disconnects (pg 7 of 9)

Most longitudinal disconnects, however, are human caused. These may take obvious form, such as dams or diversions of flow for power generation. Disconnects may be more subtle. For example, juvenile salmon in the Columbia River system perish in their downstream run to the sea in the turbines of the hydropower dams. They also have difficulty navigating through slow-moving water in the large reservoirs.




The ecological consequences of fragmenting a stream with physical barriers include:

  • Blocking fish movement and migration
  • Blocking the downstream movement of sediment
  • Disrupting nutrient and energy spiraling
  • Modifying thermal and flow regimes, often to the detriment of existing species

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