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引用本文:李茂田,孙千里,王红,刘演,赖小鹤.长江流域水库"过滤器效应"对入海溶解硅通量的影响.湖泊科学,2014,26(4):505-514. DOI:10.18307/2014.0403
LI Maotian,SUN Qianli,WANG Hong,LIU Yan,LAI Xiaohe.The filter effect of big reservoirs on dissolved silicate flux decrease in the Yangtze River drainage basin. J. Lake Sci.2014,26(4):505-514. DOI:10.18307/2014.0403
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长江流域水库"过滤器效应"对入海溶解硅通量的影响
李茂田1, 孙千里1, 王红1, 刘演2, 赖小鹤1
1.华东师范大学河口海岸学国家重点实验室, 上海 200062;2.华东师范大学地理系, 上海 200062
摘要:
根据1960-2000年间长江大通水文站记录的水、沙以及硅、氮、磷等数据,结合1954-2006年间长江流域库容大于108 m3的162座水库的库容、上游径流量、总磷等数据,利用Vollenweider模型分析了水库"过滤器效应"对入海溶解硅(DSi)通量的影响.结果表明:1)1990s相比1960s,长江入海DSi通量下降了约1.85×106 t/a,减少了大约25.3%;入海DSi通量的下降与流域径流波动、入海悬沙通量下降以及溶解无机氮通量的增加紧密相关.2)流域水库明显改变径流的自然过程,增加径流的滞留时间,流域90%以上的水库对上游径流的滞留时间超过0.05年,水库产生显著的DSi"生物过滤器"效应.模型计算显示流域大型水库对DSi的累计滞留量可达0.85×106 t/a,占年均入海DSi通量(1990-2000年)5.4×106 t的15.7%,是入海DSi通量减少量(1.85×106 t/a)的45.9%.3)根据保守估计,流域162座大型水库内泥沙累计淤积量达6.75×108 t/a,不仅使悬沙入海通量显著下降,而且造成大量颗粒吸附的外源和内源DSi颗粒沉淀,这对入海DSi通量减少也起到重要贡献.但目前对水库"泥沙过滤器"的滞留机理并不清楚,需要展开进一步的研究.
关键词:  长江流域  水库  沉积过程  溶解硅  滞留效应
DOI:10.18307/2014.0403
分类号:
基金项目:国家自然科学基金项目(41271520);崇明岛地质公园保护项目(48102860)联合资助
The filter effect of big reservoirs on dissolved silicate flux decrease in the Yangtze River drainage basin
LI Maotian1, SUN Qianli1, WANG Hong1, LIU Yan2, LAI Xiaohe1
1.State Key Laboratory of Estuary and Coastal Research, East China Normal University, Shanghai 200062, P. R. China;2.Department of Geography, East China Normal University, Shanghai 200062, P. R. China
Abstract:
Correlation method based on the historical hydrology(1960-2000) of Datong station and famous Vollenweider model based on historical dam capacity, upstream discharge and total phosphorus records(1950-2006) were used to examine the filter effect of big reservoirs on dissolved silicate(DSi) flux decrease in the Yangtze River drainage basin. The historical hydrological data of Datong station showed that the flux of DSi into East China Sea obviously decreased during 1960-2000, and the net decrease flux was 1.85×106 t/a, accounting for 25.3% of annual DSi flux in 1960s, the decreasing process of DSi flux was closely related to the processes of suspend sediment flux decreasing, dissolved inorganic nitrogen(DIN) flux increasing. The statistics result of reservoirs showed that the total capacity of 162 reservoirs reached to 155.4×109 m3, accounting for 16.8% of annual discharge to sea; furthermore, the 54 super-big reservoirs with capacity volume > 5×109 m3 including the Three Gorges Reservior, the Danjiangkou dam could contribute 87% of the total capacity of 162 reservoirs. In addition, the resident time of runoff in reservoirs was more than 0.05 year for > 90% big reservoirs. The result of the Vollenweider model showed that "biological and sediment filter effects" could occur in big reservoirs. First, the retention of DSi in 162 big reservoirs reached to 0.85×106 t/a, accounted for 45.9% of the DSi net decreasing flux of 1960-2000, and 15.7% of the annual DSi flux into sea of 1990-2000. It suggest the mechanism of "biological filter" is insufficient for explaining the DSi retention process behind reservoirs, we need to develop new mechanistic models for the retention of DSi by reservoirs. Second, the result of "sediment filter" showed that retention of sediment in 162 big reservoirs reached to 6.75×108 t/a, far more than the suspend sediment flux into sea of 3.41×108 t/a of 1990-2000, which implicated that other decreasing DSi flux maybe primarily due to the sediment filter effect.
Key words:  Yangtze River drainage basin  reservoirs  sediment process  dissolved silicate  retention effect
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