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UserName: Wijit Dharmawardene
From: wdharmaw@env.gov.ab.ca
Category: Advice
Date: 4/27/99
Time: 10:39:00 AM
Remote Name: 129.128.153.50
Questions by Brendan Ahren:
Question 1 on Scenario Without Dams: Dams are built when a need for a dam is identified. Some typical needs are, water supply, flood control, water for farming and stockwatering, development of a renewable source of power - hydro power, habitat enhancement, improvement of water quality, etc,. Dams provide very useful benefits to present day society. For example the City of New York draws over 1.2 billion gallons of water daily from its water supply dams. NYPA provides hydro power for energy needs. Some cities like Los Angeles, Phoenix, and Las Vegas depend on dams for water supply and power, for a good part of their requirements. There are no other economically viable alternatives to supply water and power to these cities in the volumes that are required. It would be difficult imagine any kind of scenario or existance for these cities without power or water supply. Please visit the website maintained by USCOLD( http://www.uscold.org, and the " Ask an Expert" question page by the Canadian Dam Association (http://www.cda.ca) for more information on the benefits from dams.
Question 2, Enenvironmental Impact: The impact on the sorroundings depends on the type of dam. Generally, only water storage dams affect the ecosystem to any significant degree. Run of river type dams and flood control dams have hardly any impact on the environment. However, during the planning, design, and consruction of a dam steps are taken to minimize and mitigate its environmental impacts. Some of the environmental impacts you may have read about in the media, are largely from dams built in the early part of this century. Again, during the re-licensing of these dams their environmental impact is assessed and action is being taken to mitigate them. Some of these older dams are also slated for decommissioning depending on their net environmental impact and benefits. Of the over 77 - 80,000 dams in USA only a few have adverse environmental impacts associated with them.
Question 3, on Hydro EnergY: Hydro energy is the cheapest renewable energy presently available. Most other abundantly available fuels like coal, gas, or oil also have environmental impacts like greenhouse gas emissions as well as from the mining and drilling processes associated with their supply. They are also non renewable forms of energy. The volume of greenhouse gas emissions associated with one 1 kWh of hydro energy is insignificant compared to that produced by fossil fuels. Nuclear energy also has problems associated with safety, disposal of nuclear waste and is nonrenewable. Currently in the US the cheapeset rates for power are in the Northeast and in the Pacific Northwest, both areas depend on hydro power.
Question 4, on Water Shortages: The water shortages in the souhthern states are due to population increase, and also their natural arid climate. Dams have provided water and power to these areas to sustain their current population, agriculture and industy.
Question 5, on what a Student Should Do: A concerned student should read up on all aspects of the dam debate - benefits and adverse impacts, and form plan of action for the future.