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作 者:杜俊[1,2] 师长兴[1] 张守红[1,2] 张鸾[1,2]
机构地区:[1]中国科学院陆地水循环及地表过程重点实验室,中国科学院地理科学与资源研究所,北京100101 [2]中国科学院研究生院,北京100049
出 处:《地理科学进展》2010年第1期15-22,共8页Progress in Geography
基 金:水利部公益性行业科研专项(2007SHZ0901034)
摘 要: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。The upper Yangtze River is the main sediment source of the Yangtze River basin and its sediment yield is closely related with its ecological environment. In recent decades, as human activities intensified strongly, sediment yield in the upper Yangtze River underwent profound changes. Using annual runoff-sediment records in the period of 1956-2007, this paper made a quantitative analysis of characteristics and causes of changes in sediment discharge of main stream and tributaries of the upper Yangtze River in different periods based on double mass curves and empirical models. Our findings are: 1. The relationship between runoff and sediment load of the main stream and tributaries of the upper Yangtze River had obvious phase characteristics, which reflected the impacts of different kinds and intensities of human activities on fluvial sediment yield and transport. The sediment discharge of the upper Yangtze River in 1994-2002 reduced 143 million tons per year and the contribution from human activities accounted for 91.2%. The main decrease was from the Jialing River. The sediment load in 2003-2007 was lowered by 450 million tons per year, of which 14.1% was induced by the reduction of runoff, 39.8% by sustaining human activities appearing in the earlier period, and 46.2% by sediment trapping in the Three Gorges Reservoir and by the decrease of sediment load in the Jinsha River. 2. The sediment discharge of the Jinsha River in the period of 1983-2000 increased by 48 million tons per year, of which 74.7% was associated with human activities, mainly construction of projects. In the period of 2001-2007, the annual sediment load of the Jinsha River was reduced by 118.3 million tons per year, all due to human activities, including various types of reservoirs among which Ertan Reservoir was the biggest one, soil and water conservation practices and decrease of sediment yield from construction projects. 3. The sediment load of the Jaling River decreased by 82.7 million tons per year in 1985-1993, of which 81.4% was relate
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