连续河水位波动对河床潜流带硝酸盐转化效率的影响  

Effect of Continuous River Water Level Fluctuations on Nitrate Conversion Efficiency in Hyporheic Zone

作　　者：张佩瑶 文章[1] 李一鸣 Zhang Peiyao;Wen Zhang;Li Yiming(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430078

出　　处：《地球科学》2024年第7期2637-2649,共13页Earth Science

基　　金：国家自然科学基金面上项目(No.42272290);国家自然科学基金重点项目(No.41830862);国家自然科学基金项目(No.U23A2042)。

摘　　要：为了探究连续水位波动下潜流带内硝酸盐的反应迁移规律,构建了包含河床沙丘的垂向二维数值模型.通过考虑不同河水位波动情况、河床坡度以及有氧呼吸、硝化和反硝化过程,系统探讨河床坡度和连续水位波动过程对溶质时空分布以及硝酸盐转化效率的影响.结果表明:河床坡度越大,地表水和周围地下水流之间会发生更快的物质交换,使溶质的浓度变化幅度变小,最终降低潜流带对NO_(3)^(-)的转化效率;较高的后续水位峰值会延长地下水潜流路径并使溶质的浓度相对变化幅度越大,然而潜流带对NO_(3)^(-)的转化效率会变低;后续水位波动持续的时间会影响溶质的时间响应,但不会影响对NO_(3)^(-)的转化效率;不同的后续水位波动延迟时间会影响NO_(3)^(-)浓度变化峰值出现的数量,延迟时间越久,越容易出现NO_(3)^(-)浓度的多峰现象.In order to investigate the reactive-transport patterns of nitrate in hyporheic zone during the hyporheic exchange process under a dynamic water level condition,a vertical two-dimensional numerical model of riverbed dune including(river)water fluctuations and sinuous river bed dune was constructed.By considering three types of river level fluctuations scenarios,river bed slope,aerobic respiration,nitrification and denitrification processes in our model,the effects of bed slope and water level fluctuatio scenarios on spatiotemporal evolution of solute distribution and nitrate conversion efficiency of hyporheic zone were systematically discussed.The results show that larger river bed slope condition can increase the solute exchange flux between surface water and the groundwater flow,and reduce the variation degree of solute concentration,which will consequently decrease the conversion efficiency of NO_(3)^(-)in hyporheic zones.Larger subsequent peak level of water fluctuations can prolong hyporheic flow path and increase the variation degree of solute concentration,whereas it can reduce the conversion efficiency of NO_(3)^(-)in hyporheic zones.The duration of subsequent water level fluctuations will affect the time response of solute concentration,but will not affect the conversion efficiency of NO_(3)^(-).Different delay times of subsequent water level fluctuations will affect the humber of NO_(3)^(-)concentration peaks.Furthermore,longer delay time can result in multiple peaks of NO3-concentration.

关 键 词：连续水位波动 河床潜流带 硝酸盐转化效率 反应迁移模拟 水文地质 

分 类 号：P641.2[天文地球—地质矿产勘探]