Rapid siltation

Rapid siltation of lakes is the result of soil erosion accelerated by the overuse of farming and grazing lands, deforestation, the over-harvesting of fuelwood, and other imprudent land uses in lake catchment areas.

This is a very serious problem facing many lakes and reservoirs in China, India, Africa, and other less developed countries. Particularly alarming is the fact that cultivated fields and pastures, which have been sustainably used as more or less stationary semi-natural systems for centuries, are being devastated almost irreversibly by overuse. Overpopulation, as well as the residents' strong desire for more cash income to buy imported industrial products, has encouraged the abandonment of traditional sustainable methods of land use. The same situation is causing desertification in arid regions and forest destruction in the humid tropics.

The silt load of lake water, indicated by the concentration of suspended solids, is significantly correlated with the area of cultivated land per lake water volume in lakes in humid/subhumid climates, as illustrated in figure 3.3. A correlation in the arid zone could not be detected owing to the scarcity of available data.