Países desarrollados desmantelan represas y países subdesarrollados las fomentan indiscriminadamente
In the U.S., where the rate of decommissioning of old dams is greater than the rate of building new, the debate is perhaps as strong as in India, but qualitatively different, as India along with China are the countries where more dams are built today.
LOS PAÍSES DESARROLLADOS DESMANTELAN LAS GRANDES REPRESAS, LOS TERCERMUNDISTAS LAS CONSTRUYEN FUERA DE MINIMA PLANIFICACIÓN.
Represa Elwah - será desmontada en 2014, está cerca de Port Angeles, Washington. Será desmantelado para permitir la migración y los flujos de peces. Esta cosa fea fue construida alrededor de 1914, se desmantelará a un costo de 300 millones de dólares. Se encuentra ubicada en el Parque Nacional Olimpic.
Elwah Dam - to be dismantled by 2014 - Elwha Dam is near Port Angeles, Washington. It will be dismantled to provide open river for fish flows. This ugly thing was built around 1914, but should be gone around 2014 at a cost of $300 million. It is located in Olympic National Park. www.flickr.com/photos/50087332@N00/2265785208/
Desmantelamiento de la represa milltown.
Dam Removals Open Way for Cultural and Habitat Restoration
Dam Removals Open Way for Cultural and Habitat Restoration Posted on October 22, 2010
The beginning of the removal of the Milltown Dam. blogs.nationalgeographic.com/blogs/news/chief...
LA INICIATIVA DE GRANDES REPRESAS SE TOMA SOBRETODO POR CRITERIOS ELECTORALES O POR LA “TAJADA OBLIGADA” DE LAS GRANDES OBRAS PUBLICAS
EL PROBLEMA SOCIOAMBIENTAL “SE PATEA PA´DELANTE” Y LOS QUE RECIBAN LA POSTA EN EL GOBIERNO “YA PUÉS…QUE VEAN!!!”
Entre las alternativas a las grandes represas, se tiene los sistemas descentralizados de suministro de agua y energía en pequeña escala, el aumento de la eficiencia en el suministro y en los usos finales y manejo de la demanda. Frecuentemente se ha escogido construir represas cuando otras opciones podrían alcanzar los objetivos de agua y energía a un costo inferior, o brindar los beneficios de un desarrollo mas sustentable y mas equitativo.
Las cuestiones que se plantean en torno a las represas son las mismas que se plantean en torno al agua, al modo en que se toman decisiones relacionadas con el agua, y a como se evalúa la contribución que un proyecto hace al desarrollo.
Los problemas están todos relacionados con el impacto que tendrá la represa sobre el curso del río; con los derechos de acceso al agua y a los recursos del río; con la posibilidad de que la represa desarraigue los asentamientos existentes, afecte la cultura y los medios de subsistencia de las comunidades locales, y reduzca o degrade los recursos ambientales; y también con la cuestión de si la represa representa la mejor inversión económica de fondos y recursos públicos.
El debate es en parte acerca de lo que ocurrió en el pasado y continúa ocurriendo hoy, y en parte acerca de lo que pueda suceder en el futuro si se construyen más represas.
En algunos países, está impulsado fundamentalmente por preocupaciones sociales y ambientales específicas; en otros, por consideraciones más amplias en materia de desarrollo.
En Estados Unidos, donde la tasa de desmantelamiento de viejas represas es mayor que la tasa de construcción de nuevas, el debate es quizá tan intenso como en la India, pero cualitativamente diferente, puesto que la India junto con China son los países donde más represas se construyen hoy en día.
Existen opciones para satisfacer las necesidades de agua y energía, que a menudo han sido ignoradas a pesar de ser mejores más baratas y benignas que las grandes represas.
DESMANTELAMIENTO DE REPRESAS (DAMS DISMANTLE)
Centuries-old dams is removed from Musconetcong River | NJ.com 25 Feb 2009 … The dam dismantling, which began Feb. 11, was completed Monday. … to preserve and restore aquatic habitats in the United States, …www.nj.com/…/centuriesold_dams_removed_from.html –
Dam Decommissioning | International Rivers Currently, the United States – with some 74000 dams (most of which are … around the country have launched campaigns to dismantle dams in their communities, … When the cost of maintaining an old dam exceeds the receipts from power …www.internationalrivers.org/node/571 –
EXPLORER; Dams Go Down, Uncorking Rivers For Kayakers – New York Times 9 Aug 2009 … In the 1950s and ’60s, a dam went up in the United States every six … River by river, old dams are being dismantled at a rate of about 40 …
query.nytimes.com/gst/fullpage.html?res…sec…all -
How to Fix Our Dam Problems | North America > United States from … His concerns are widely shared in the United States-not to mention in dry Australia, … in the Klamath River drainage 22 dams were dismantled at a total cost of $3000. ….. How many old dams are we talking about repairing or removing? …
http://www.allbusiness.com/government/…/10635450-1.html -
News briefing: 8 October 2009 : Nature News 6 Oct 2009… producer of academic research papers in the world behind the United States, … The excerpt was released on 6 October to coincide with United Nations … old dams should be dismantled (dismantling dams) all over the world. … Dismantling dams, on the contrary, is the simplest, if not the only … http://www.nature.com/news/2009/091007/full/461702a.html -
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Overview of Dam Decommissioning
www.crrel.usace.army.mil/.../overview.htm
Overview of Current Dam Decommissioning Activities,
a power point presentation by Kate White.
Engineering and Ecological Aspects of Dam Removal—An Overview.
(Jock Conyngham, J. Craig Fischenich, Kathleen D. White)
Definition of Dam Decommissioning:
Dam decommissioning is the range of options for dams that are no longer useful. These options range from the staged removal of dam structures, to partial modification. There is no generic approach to dam decommissioning and river restoration. A solution is needed that addresses the particular characteristics of each dam and river.
Dam Dismantling:
Kenebec River before (left) and after (right)
the removal of Edwards Dam
This is the most dramatic option, involving the complete dismantling of all physical barriers to stream flow. The intention here is to fully restore the natural flow of the river, including peak flows and seasonal flooding. This would also enable fish passage and the transport of gravel and organic debris downstream. Dam removal can sometimes be immediate, but more often it is staged in a cautious, risk-averse way to avoid unwanted release of the sediments that typically accumulate behind old dams.
Reasons that Dams are No Longer Useful:
•Public Health and Safety Concerns:
FEMA estimates 58,000 (85% of NID) large dams will exceed their design life span by 2020. ASCE reported 61 dam failures and 520 incidents, 2100 structures classified as unsafe (2001). High cost to repair (plus liability).
Ecological:
Failure of efforts to restore threatened and endangered or economically and ecologically significant species affected by the dam. Alternatives to dams may now be available.
Socioeconomic:
Community contexts and values have changed.
Partial Dam Dismantling:
This option alters the dam structure, restores flow, and permanently changes the dam's original function. However, some of the dam may be left intact, recognizing that complete removal of dams may not always be the best option for a river. For example, remnant structures may serve to stabilize reservoir sediment, or provide a limited buffer against flooding. Also, partial alteration helps to avoid the expense of complete removal. Dam decommissioning can provide these benefits while still achieving the ecological objectives of improved fish passage and greater in-stream flows.
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Costs of Dams
http://www.crrel.usace.army.mil/sid/Dam_decom/pdfs/Overview_Dam_Decommissioning.pdf
•Ecosystem impacts•
Water quality impacts•
Legal and financial liability•
Safety•
Maintenance requirements for structure, headpond, associated erosion•
Impacts on T&E populations•
Recreation associated with unregulated hydrography an ecological integrity•
Archaeological and aesthetic impacts
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