1998-2019年三峡水库总磷浓度与形态变化及通量汇算
Variation of Concentration,Form and Flux of Phosphorus in the Three Gorges Reservoir from 1998 to 2019
娄保锋 1余明星 1黄波 1杨妍 1林晶晶1
作者信息
- 1. 生态环境部长江流域生态环境监督管理局监测与科研中心,武汉 430010
- 折叠
摘要
研究 1998-2019年三峡水库磷浓度及形态变化,并进行通量汇算.研究时段分为 3个阶段:1998-2002年(阶段 I,三峡水库运行之前)、2003-2012年(阶段 II,过渡时期)和 2013-2019年(阶段 III,三峡水库实现 175 m正常蓄水位,且金沙江下游段向家坝水库运行后),以阶段 I和 III为重点时段进行对比分析.结果表明,随着三峡成库、水位抬高及金沙江向家坝水库和溪洛渡水库的运行,三峡水库悬浮泥沙浓度值已降至很低(常年回水区 2013-2019年均值为 42 mg/L,丰水期均值为 96 mg/L).22年间,泥沙入库量和出库量皆呈下降趋势.三峡成库后的 2003-2012年,泥沙淤积量巨大(平均 1.546亿 t/a);向家坝成库后的 2013-2019年,泥沙淤积大为减少,淤积量仅为 2003-2012年的 37%.2013年是三峡库区磷污染程度由加重趋势至减轻趋势的拐点,之后三峡水库总磷和溶解态磷浓度皆呈显著下降趋势.三峡水库磷的主导形态由颗粒态变为溶解态,溶解态磷占比由成库前的 39%上升为 2017-2019年的 69%.2004-2012年是总磷滞留的高峰期,期间总磷入库量大且年际波动大,约 60%的磷随泥沙发生沉降,年均滞留量为 8.222万 t/a;2013-2019年,总磷入库量大幅度减小且年际波动变小,入库和出库磷通量趋于平衡.总磷、溶解态磷和颗粒态磷通量均表现为丰水期>平水期>枯水期.河流泥沙总磷浓度与泥沙含量正相关的实质是颗粒态磷浓度与泥沙含量的正相关.总磷浓度、通量和形态发生变化的主要驱动力是泥沙含量下降和磷污染控制.
Abstract
The changes in total phosphorus(TP)concentration and form in the Three Gorges Reservoir(TGR)from 1998 to 2019 were studied,and P fluxes were calculated.The entire research period was divided into three stages:1998-2002(stage I,before the operation of the TGR),2003-2012(stage II,as a transitional period),and 2013-2019(stage III,after the TGR achieved the normal water level of 175 m and Xiangjiaba Reservoir began to operate).Comparative analysis was mainly on Stages I and III.The results show that the concentrations of suspended sediment(SS)in the TGR decreased to a very low level(average 42 mg/L during 2013-2019 period and 96 mg/L in wet season).From 1998 to 2019,the inflow and outflow of sediment amount showed a downward trend.A huge amount of sediment was retained at the bottom of the reservoir during 2003-2012(average 154.6 million t/a),while in 2013-2019,the amount of sediment deposition significantly decreased and the sedimentation amount was only 37%of that in 2003-2012.Year 2013 marked a turning point in the trend of phosphorus pollution in TGR from increasing to decreasing.Afterwards,concentrations of TP and DP(dissolved phosphorus)showed a significant downward trend.The form of phosphorus in TGR changed from mainly granular to dissolved,and the percentage of DP in TP in the perennial backwater area increased from 39%before TGR formation to 69%during 2017-2019.2004-2012 was a period with high deposition for TP when the amount of TP entering the reservoir was large and fluctuated vastly between years,and approximately 60%of phosphorus was trapped(82220 t/a).From 2013 to 2019,there occurred significantly decrease in the TP amount entering the reservoir in accompany with diminishing interannual fluctuation,tending to a balance between input and output of P.Fluxes of TP,DP,and PP(particulate phosphorus)all show a pattern of wet season>even season>dry season.The main driving forces for changes in TP concentration,flux,and form are the reduction in SS concentration and phosphorus pollution level.
关键词
长江/三峡水库/磷/通量/形态Key words
Yangtze River/the Three Gorges Reservoir/phosphorus/flux/form引用本文复制引用
基金项目
国家自然科学基金长江水科学研究联合基金(U2240213)
三峡工程生态与环境监测合同项目(JJ[2015-008])
三峡工程生态与环境监测合同项目(JJ[2015-047])
三峡工程生态与环境监测合同项目(JJ[2016-012])
出版年
2024
国家科技期刊平台
NSTL
万方数据