For many years, mechanical dredging has been the solution for dying ponds, lakes, retention basins, and rivers. Dredging removes sediment, some excess nutrients, pollutants and organic matter. By increasing the depth in this way, weed growth is discouraged, water temperature lowered and oxygen levels may be increased. Although mechanical dredging can help in these ways, it only solves part of the problem, and causes other issues.
Mechanically removing sediment is extremely disruptive to the aquatic ecosystem, not to mention costly transportation of the sediment to a landfill or other site.
Removing sediment and organic matter also removes the plants and animals of the bottom-dwellingcommunity, which form the basis of life for higher animals. Furthermore, mechanical dredging does not often consider what the natural contours of a waterway should be. Near-shore areas are deepened, eliminating shallow habitats, spawning and rearing grounds, changing natural flow patterns and precluding recreational uses such as swimming. The sudden increase in turbidity further degrades water quality, stressing fish and other organisms, sometimes fatally. The changes in light patterns throw off reproductive cycles. It can take months for the water to settle down, and in the end, the system is still completely unbalanced.