such flats had reached 10,000 km. The type of desertification caused by year-round pasturing of cattle has been termed the most devastating in Central Asia, with the gravest situations in Turkmenistan and the Kazakh steppe along the eastern and northern coasts of the Caspian Sea. Wind erosion and desertification also are severe in settled areas along the Garagum Canal; planted windbreaks have died because of soil water-saturation and / or salinization. Other factors promoting desertification are the inadequacy of the collector-drainage system built in the 1950s and inappropriate application of chemicals. The Aral Sea Turkmenistan both contributes to and suffers from the consequences of the desiccation of the Aral Sea. Because of excessive irrigation, Turkmen agriculture contributes to the steady drawdown of sea levels. In turn, the Aral Sea's desiccation, which had shrunk that body of water by an estimated 59,000 square kilometers by 1994, profoundly affects economic productivity and the health of the population of the republic. Besides the cost of ameliorating damaged areas and the loss of at least part of the initial investment in them, salinization and chemicalization of land have reduced agricultural productivity in Central Asia by an estimated 20–25%. Poor drinking water is the main health risk posed by such environmental degradation. In Dashhowuz Province, which has suffered the greatest ecological damage from the Aral Sea's desiccation, bacteria levels in drinking water exceeded ten times the sanitary level; 70% of the population has experienced illnesses, many with hepatitis, and infant mortality is high. Experts have warned that inhabitants will have to evacuate the province by the end of the century unless a comprehensive cleanup program is undertaken. Turkmenistan has announced plans to clean up some of the Aral Sea fallout with financial support from the World Bank. Chemical pollution The most productive cotton lands in Turkmenistan (the middle and lower Amu Darya and the Murgap oasis) receive as much as 250 kilograms of fertilizer per hectare, compared with the average application of thirty kilograms per hectare. Furthermore, most fertilizers are so poorly applied that experts have estimated that only 15–40% of the chemicals can be absorbed by cotton plants, while the remainder washes into the soil, and subsequently into the groundwater. Cotton also uses far more pesticides and defoliants than other crops, and application of these chemicals often is mishandled by farmers. For example, local herdsmen, unaware of the danger of DDT, have reportedly mixed