Biodiversity

(An excerpt from Silenced Rivers: The Ecology and Politics of Large Dams, by Patrick McCully) "You fish people are very skilful in getting these fish into cans. Cannot you be just as skilful in getting these fish to be raised up over a dam?" - Comment at public hearing on a proposal for the first dam on the mainstream of the Colombia River, 1924 The annual run of adult salmon and steelhead trout in the huge Columbia River basin — which covers an area larger than France — is estimated to have averaged between 10 and 16 million fish before non-native settlers first arrived

An excerpt from the book Rivers for Life: Managing Water for People and Nature, which explores the unhealthy state of the world’s rivers following decades of industrial damming, diversions and other insults, and describes the tools and techniques that could be used to restore them back to health. The following excerpt, from the book’s last chapter, asks the tough questions: What will it take to change our destructive ways before it is too late? No generation before ours would have asked the question posed in this title. It has an ominous ring: how can it possibly be up to us to save

Low flows below dams killed thousands of salmon on the Klamath in 2002 The environmental consequences of large dams are numerous and varied, and includes direct impacts to the biological, chemical and physical properties of rivers and riparian (or "stream-side") environments. The dam wall itself blocks fish migrations, which in some cases and with some species completely separate spawning habitats from rearing habitats. The dam also traps sediments, which are critical for maintaining physical processes and habitats downstream of the dam (include the maintenance of productive deltas, barrier