Ecological Threat to Lakes and Reservoirs

Definition

Lakes and reservoirs hold about 90% of the world’s fresh surface water. According to the discussions at the 9th International Conference on the Conservation and Management of Lakes held in Shiga, Japan, in 2001, warning was given of some one billion people being at risk from overuse, water withdrawals, and pollution of these water bodies. Similar warnings were given at the 3rd World Water Forum at the Kyoto Conference in 2003.

The principal threats worldwide appear to be:

• Accelerated eutrophication, which affects 54% of the lakes in the Asia-Pacific region, 53% in Europe, 28% of those in North America, and 41% of those in South America

• Chemical pollution, which is the second most commonly cited threat to lakes

• Alien plant and animal species, either introduced into lake environments in the ballast water of ships, as part of the aquarium trade, from small boats traveling between lakes, or in bait and by escaping from aquaculture, with some intentionally introduced to boost...