Tens of thousands of old dams in the eastern U.S. no longer power machinery, but they still hold the toxic legacy of the agricultural and industrial expansion of non-indigenous settlers. A team of Earth scientists has found that, as the decrepit dams are removed, they release stores of lead, phosphorus, copper and other chemicals into the Chesapeake Bay and other waterways.
Even small streams could be turned into a source of water power for grist, flour, saw, and other types of mills. Sediment samples from mill ponds behind dams in Cumberland County, Pennsylvania, showed the march of development across the area. During the 18th century, iron ore mining and paper mills began to deforest the region. The runoff left sand deposits in the ponds with traces of iron slag and charcoal. Â From: Old dams hold a toxic legacy,Â Analysis byÂ Tim WallÂ ,Â Fri Oct 19, 2012 07:54 AM ETÂ http://news.discovery.com/earth/old-dams-hold-a-toxic-legacy-121019.html#mkcpgn=rssnws1
The current talk about removing the Mactaquac dam begs the question … What does lurk beneath the surface and what energy losses will we incure? Perhaps its time to rethink conventional environmental management? Art MacKay
OPINION: Removing dams .. beware the toxic legacy beneath the beauty.