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What are people doing to improve the impact of dams?
Seattle City Light (#) is
voluntarily raising river flows downstream of the Ross Dam on Skagit Rive to
save salmon nests downstream. Read more in the Dam News!
Lower
Snake River (#) dams have done the same, helping spring migration of
endangered fish like chum and steelhead, species of salmon.
Five small dams in California will be decommissioned, flows will be
increased, fish ladders will be enlarged, and screens will be placed on
turbines to help runs of winter, spring, fall, and late-fall chinook and
steelhead on Battle Creek. Fish often must pass through turbines (which make
electricity) to pass a dam. The fish are disoriented when they emerge and
cannot continue on their journey.
The Flat Rock Dam in Philadelpha County, PA (#) will soon have new fish
ladders to help shad, striped bass, and other fish travel up the Schuylkill
River. The dam, a 21 ft-high concrete gravity dam, was built in 1977 for
recreation purposes. A budget of $21.8 million has been allocated for
the project, which is estimated to bring in $2.5 million in
fishing trip revenues once it's complete.
PR Newswire:
PA Dept of Envr Protection press release, 6/11/99
Two dams are going down near Portland, Oregon: Marmot Dam (Marmont in the
National Inventory
of Dams (#)) on the Sandy River and Little Sandy Dam on the Little Sandy
River. The Marmot is 87 years old
and 40 feet high and supplied water and hydroelectric power (type other). The
breach (*) of these dams will allow for passage of salmon and steelhead,
prompted by the listing of theses fish as threatened species. The project cost
projection is $10 million and should take 2 years. It is reported that the
structures will actually be removed.
Read about more problems and solutions in the Dam News!
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What's your opinion on the societal impact of dams? |
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Authorities, politicians, and engineers have to take both the advantages and disadvantages
into account when planning a dam
or considering its decommission. If a dam is being built, they also have to consider what type of dam
should be built. The design of the dam, the size
and shape, must also be considered, and is usually dealt with by the Civil Engineers.
There are many different types of dams, as we
noted earlier. We'll tell you about four types of dams. |
What are some different
types of dams?
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