洞庭湖泥沙沉积与土壤侵蚀

洞庭湖是一个吞吐型的过水湖泊,其泥沙沉积量大,1951～1983年累计沉积泥沙约48.07亿t,年平均沉积1.5亿t。泥沙沉积于汛期,多为长江冲积物。严重的泥沙淤积,反映出长江中上游地区土壤侵蚀十分强烈。泥沙沉积灾害发生在湖区,突出表现为洪涝、土壤潜育化和血吸虫感染。侵蚀灾害发生在山丘区,它导致土壤退化和滑坡、泥石流灾害加剧。加强长江上游水土流失重点防治和中上游防护林工程体系建设,提高人均产值,消除或减轻人口增长对生态环境造成的压力,可从根本上控制土壤侵蚀和泥沙沉积灾害。

Soil Erosion and Sediment Deposition in Dongting Lake

Dongting Lake is an alternately filled lake with large amount of sediment deposition. Sediment deposited from 1951 to 1983 added up to about 4807 million tons with an average sediment deposition of 150 million tons per year. The sediment deposited mainly in the flood season, of which, majority were alluvial deposits coming from the Yangtze River. Serious silt accumulation reflects the intensive soil erosion in the upper and middle Yangtze River. The disasters due to silt deposition took place in the lake area and mainly expressed in flooding, soil gleization and snail fever. Soil erosion took place in mountainous area and led to soil deterio-ration and the sharpenness of slide and debris flow. Strengthening the prevention of soil loss in the key areas in upper Yangtze River basin and the establishment of forest system in the upper and middle basin, increas-ing per capita output and eliminating or lessening the pressure of population growth on the ecologic environ-ment can basically put the disasters ,due to soil erosion and sediment deposition under control.