Running head: IMPACT OF DAMS ON ANADROMOUS FISH

The Impact of Hydropower Dams on California's Populations of Anadromous Fish: What Can be done to mitigate the Dams Effects and Restore California's Watersheds.
Russell Cole
Western Governors University The Impact of Hydropower Dams on California's Populations of Anadromous Fish: What can be done to mitigate the Dams Effects and Restore California's Watersheds.

The indigenous people of California were completely dependent on the seemingly infinite quantities of salmon and steelhead that annually returned to their coastal rivers. Upon their arrival, European settlers soon developed a commercial fishing industry, which supported them very well. Today, however, that never-ending
It was obvious that a large dam would impede the migration of fish attempting to return to their breeding areas. On many of the dams no attempt was made to include a fish passage, such as a fish ladder. Many of these dams were simply too tall to incorporate a system of fish passage and therefore designers accepted the fish impediment as unavoidable. With anadromous fish unable to return to much of their critical habitat, the next question to be asked should have been, what effects would the dams have on the section of river below the dam known as a tail water? With dam operators determining downstream flows, based on various water demands or electricity producing needs, would fish be subjected to extremes of either too much or too little water? Additionally, would the quality of the water being released from the dam be substandard in areas such as water temperature and clarity? Water released from the top of a reservoir in summer can warm a river to temperature ranges above those usually found in free flowing streams, higher temperatures that can be harmful, if not fatal to salmonids. Sediments, which quickly build up behind dams, are also released into the tail waters. This sedimentation of rivers has profound effects on its ecosystem, the killing off of macroinvertabrates, the main food source of salmonids, and the