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利用1956-2007年径流—输沙序列,分期定量研究了长江上游近期主要干支流输沙变化及其原因,结果显示:①长江上游1994-2002年输沙量减少1.43亿t/a,人为减沙占91.2%,主要来自嘉陵江措施减沙;2003-2007年减沙4.50亿t/a,径流减沙占14.1%,前期持续的人类活动减沙占39.8%,三峡水库蓄水拦沙、金沙江措施减沙等新增人为减沙占46.2%。②金沙江1983-2000年输沙量增加0.48亿t/a,人为增沙占74.7%,主要是工程增沙;2001-2007年输沙量减小1.183亿t/a,全部为人为减沙,包括二滩等各型水库拦沙、水保减沙和工程增沙减少。③嘉陵江1985-1993年输沙减少0.827亿t/a,人为减沙占81.4%,主要人为减沙包括农村社会经济因素变化导致的土壤减蚀和水库拦沙;1994-2007年输沙量减少1.285亿t/a,其中自然径流减沙占29.6%,前期持续人类活动减沙占42.1%,宝珠寺等新增水库拦沙和水保减沙占23.4%,另有4.9%的人为减水减沙。
Using the sequence of runoff and sediment transport from 1956 to 2007, the change of sediment transport and its causes in the main upstream and downstream of the upper reaches of the Yangtze River were studied by stages. The results showed that: (1) Sediment discharge decreased by 143 million t / a from 1994 to 2002 in the upper reaches of the Yangtze River, Accounting for 91.2% of the total sand, mainly due to sediment reduction by Jialing River measures; 450 million t / a of sediment reduction in 2003-2007, 14.1% of runoff and sediment reduction, 39.8% of sediment reduction in the previous period, Sediment reduction and other new sediment reduction measures accounted for 46.2%. ② The sediment discharge increased by 48 million t / a from 1983 to 2000 in the Jinsha River, accounting for 74.7% of the man-made sediment discharge, mainly due to the increase of sediment; the sediment discharge in the period from 2001 to 2007 decreased by 118.3 million t / a, all of which were man-made sediment reduction , Including various types of reservoirs such as Ertan retaining sediment, sediment reduction and water and sediment reduction projects. ③ Sediment transportation in Jialing River decreased by 82.7 million t / a from 1985 to 1993, accounting for 81.4% of the total man-made sediment discharge, and mainly from man-made sediment reduction including soil erosion reduction and reservoir sediment reduction due to changes in rural social and economic factors. Sediment discharge decreased from 1994 to 2007 1.285 trillion t / a, of which 29.6% were runoff from natural runoff and 42.1% from the previous human activities, and 23.4% from newly added reservoirs such as Baozhusi Reservoir and sand and sediment reduction. Another 4.9% were man-made water-reducing Sediment reduction.