This is from Waterforum Digest 363

Date: Wed, 7 Mar 2001 22:47:10 -0500
From: "Laurie Duker" <[log in to unmask]>
Subject: Re: World Water Resources
Regarding the impact of damming on water quality and quantity, visit
LakeNet's website at http://www.worldlakes.org. The pages on Water
Diversion provide a discussion of the problem, promising strategies, photos
and links. Water diversion is having a devastating effect on innumerable
lakes around the globe, the largest being the Aral Sea, which has lost 2/3
of its volume. Fisheries at the Aral Sea have been completely destroyed.
The website also has information on more subtle impacts of damming on water
quality, including the possible deoxygenation of lake waters below dams due
to a reduction in sediments that under natural circumstances would create
deep currents which mix oxygen into the lake water. A study at Lake Geneva
suggests that dams above the lake are starving the lake of oxygen, leading
to toxic phosphates and heavy metals being released from lake soils.
Laurie Duker
Conservation Director
LakeNet