ABOUT EROSION
 Landslides, clear-cut, strip mines & floods...
These environmental scars are an assault on our environmental consciousness. At their onset, they are cause for alarm-left unchecked; their effects can be devastating.
Erosion and sedimentation cause both environmental and economic impacts. Eroded soil contains nitrogen, phosphorus and other nutrients, which reduce water clarity, trigger algae blooms, deplete oxygen, and kill fish. Increased sediment deposits in channels lead to increased stream bank erosion which destroys streamside vegetation, and aquatic and wildlife habitat.
Excessive sedimentation reduces reservoir storage capacity, which requires frequent and costly dredging and removal. Erosion also severely diminishes the ability for the soil to support plant growth. Ironically, in many cases it is plant growth that has the strongest capacity to halt the process.
 One of the most important impacts of erosion and sedimentation in the Pacific West is the reduction of aquatic habitat and spawning habitat for already declining fisheries. Trout and salmon require a high quality environment free of silt and mud in order for successful reproduction to occur.
Siltation of salmon streams can kill eggs and fry because of insufficient oxygen or inadequate removal of waste products (carbon dioxide and ammonia). Sediment can also form a physical barrier to fry emergence by blocking the route of movement from the gravel.
Accumulation of sediment in the gravel reduces the number of aquatic insects available for fish food. Siltation alters the stream bottom physically, causing an elimination or reduction of these organisms. In general, sedimentation reduces both the kinds and numbers of organisms and populations in a stream. The general health of the aquatic habitat is affected and deterioration of habitats in turn produces less fish. This can have a profound effect on the economics of fisheries as well as wildlife species depending on this food source.
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