| 城市小型河流水动力弥散和潜流交换过程 |
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| 引用本文： | 于靖,张华.城市小型河流水动力弥散和潜流交换过程[J].水科学进展,2015,26(5):714-721. |
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| 作者姓名： | 于靖 张华 |
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| 作者单位： | 1.中国科学院烟台海岸带研究所海岸带环境过程与生态修复重点实验室, 山东 烟台 264003; |
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| 基金项目： | 国家自然科学基金资助项目(41271506);中国科学院重点部署项目(KZZD-EW-14) |
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| 摘 要： | 为研究城市小型河流中污染物的物理迁移过程规律,分析基流条件下流动水体与暂态存储区之间的滞留交互作用,采用溴化锂(LiBr)作为保守性示踪剂进行野外现场示踪试验,结合一维溶质运移存储模型(One-dimensional Transport with Inflow and Storage model, OTIS)定量解析潜流交换特性,估算纵向弥散系数(D)、潜流交换面积(As)、主河道断面面积(A)和潜流交换系数(α).模型度量指标DaI值和均方根误差值结果表征参数模拟结果可靠性高,拟合效果理想.由泵入点O至下游1 300 m设置的A、B、C、D 4处监测点的模拟结果表明,水文参数D、As、A和α均随水文条件而变,OB河段(0~600 m)潜流交换能力较弱,主要以对流弥散过程为主;BD河段(600~1 300 m)具有较强的暂态存储能力,对溶质的滞留时间长;BC(600~1 000 m)和CD(1 000~1 300 m)河段交换系数分别为(3.42×10-6±0.65×10-6)s-1和(2.87×10-6±0.81×10-6 )s-1;河段BC存在2.2×10-5m3/(s·m)的侧向补给流量.4个河段对比发现,城市河流渠道化、河床沉积物贫瘠等特征导致潜流交换能力弱化.
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| 关 键 词： | 城市河流 物理迁移 暂态存储 保守性示踪剂 一维溶质运移存储模型 |
| 收稿时间： | 2015-01-19 |
Hydrodynamic dispersion and hyporheic exchange in a small urban stream |
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| YU Jing,ZHANG Hua.Hydrodynamic dispersion and hyporheic exchange in a small urban stream[J].Advances in Water Science,2015,26(5):714-721. |
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| Authors: | YU Jing ZHANG Hua |
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| Institution: | 1.Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China;2.University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | To reveal the physical transport processes in a small urban stream and analyze exchange processes between water column and transient storage zone under base flow, field experiment using LiBr as conservative tracer and numerical simulation using One-dimensional Transport with Inflow and Storage model (OTIS) were carried out to quantitatively characterize hyporheic exchange. The longitudinal dispersion coefficient (D) reach-scale transient storage area (AS), main channel cross section area (A), and the hyporheic exchange coefficient (α) were estimated along a 1 300 m stream reach. Transient storage metrics DaI and ERMS values showed an excellent fit of the model. The results of four stations (A, B, C and D) downstream the location of tracer injection demonstrated that hydrological parameters D, AS, A, α varied with hydrological conditions. The hyporheic exchange of upper reaches (0-600 m) was weak and convection and dispersion were dominant processes. The middle reaches of the river (600-1 300 m) had stronger transient storage and longer hydraulic retention time. The exchange coefficient of segment BC (600-1 000 m) and CD (1 000-1 300 m) were (3.42×10-6±0.65×10-6) s-1 and (2.87×10-6±0.81×10-6) s-1, respectively. A lateral flow of 2.2×10-5 m3/(s·m) contributed to BC. In general, stream channelization and lack of sediment on the streambed reduced the capacity of hyporheic exchange in urban streams. |
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| Keywords: | urban stream physical transport transient storage conservative tracer tests One-dimensional transport with inflow and storage model |
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