Impact of dams on Yangtze River sediment supply to the sea and delta intertidal wetland response
Impact of dams on Yangtze River sediment supply to the sea and delta intertidal wetland response
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DOI：
10.1029/2004jf000271
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发表时间：
2005-09
影响因子：
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通讯作者：
Shi-lun Yang;Jing Zhang;J. Zhu;Joseph P. Smith;S. Dai;A. Gao;P. Li
中科院分区：
文献类型：
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作者：
Shi-lun Yang;Jing Zhang;J. Zhu;Joseph P. Smith;S. Dai;A. Gao;P. Li
[1]在估算水库泥沙淤积量的基础上，分析了长江流域5万座水坝对泥沙供应和潮间带湿地响应的影响。水库总蓄水量为200 × 109 m3，占长江年径流量的22%。水库泥沙淤积率由1950年的100万t/a增加到2003年的850万t/a以上。虽然产沙量增加了更广泛的流域土壤侵蚀，总的河流泥沙排放率显示出强烈的下降趋势，从20世纪60年代末至2003年，可能是由于大坝建设。因此，三角洲前缘潮间带湿地的总增长率急剧下降。潮间湿地的生长速率与河流泥沙供给之间存在着显著的相关性，这表明河流泥沙供给是三角洲湿地年际至年代际演变的主导因素。对潮间湿地生长速率与泥沙供应量的回归分析表明，当河流输沙率达到<263 × 106 t/yr的阈值水平时，三角洲前缘潮间湿地退化。由于三峡大坝和其他新大坝的建设，长江的输沙量很可能在未来几十年内减少到150 × 106 t/年以下。因此，除非现行的管理政策得到调整，否则长江三角洲潮间带湿地将出现急剧衰退。
[1] On the basis of estimates of sediment accumulation in reservoirs, the impact of 50,000 dams on sediment supply and intertidal wetland response in the Yangtze River catchment is examined. The total storage capacity of reservoirs is 200 × 109 m3, or 22% of the Yangtze annual runoff. The sediment accumulation rate in reservoirs has increased from ∼0 in 1950 to >850 × 106 t/yr in 2003. Although sediment yield has increased with broader soil erosion in the river basin, the total riverine sediment discharge rate shows a strong decreasing trend from the late 1960s to 2003, likely due to dam construction. Consequently, the total growth rate of intertidal wetlands at the delta front has decreased dramatically. A significant relationship exists between intertidal wetland growth rate and riverine sediment supply that suggests riverine sediment supply is a governing factor in the interannual to interdecadal evolution of delta wetlands. Regression analysis of intertidal wetland growth rate and sediment supply shows that intertidal wetlands at the delta front degrades when the riverine sediment discharge rate reaches a threshold level of <263 × 106 t/yr. Owing to the construction of the Three Gorges Dam and other new dams, the sediment discharge rate of the Yangtze River will most likely decrease to below 150 × 106 t/yr in the coming decades. Therefore unless current management policies are adjusted, drastic recession of Yangtze River delta intertidal wetlands can be expected to occur.