Predicting Solute Transport Through Green Stormwater Infrastructure With Unsteady Transit Time Distribution Theory
Predicting Solute Transport Through Green Stormwater Infrastructure With Unsteady Transit Time Distribution Theory
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DOI：
10.1029/2020wr028579
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发表时间：
2021-02
影响因子：
5.4
通讯作者：
E. Parker;S. Grant;Y. Cao;M. Rippy;K. McGuire;P. Holden;M. Feraud;S. Avasarala;H. Liu;W. Hung;M. Rugh;J. Jay;J. Peng;S. Shao;D. Li
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作者：
E. Parker;S. Grant;Y. Cao;M. Rippy;K. McGuire;P. Holden;M. Feraud;S. Avasarala;H. Liu;W. Hung;M. Rugh;J. Jay;J. Peng;S. Shao;D. Li
在这项研究中，我们探索了使用非稳定渡越时间分布(TTD)理论来模拟生物滤池中的溶质传输，生物滤池是一种流行的基于自然或绿色的雨水基础设施(GSI)。TTD理论有可能解决与预测污染物通过这些系统的去向和传输相关的许多悬而未决的挑战，包括水平衡的不稳定(随时间变化的流入、流出和储存)、污染物负载的不稳定、依赖时间的反应以及扩大到GSI网络和城市集水区。从均匀抽样下非定常年龄守恒方程的解出发，我们得到了一次或多次风暴过程中和之后溶质突破的显式表达式。该解决方案使用来自17个模拟风暴的突破性数据进行了校准和验证，这些数据来自南加州的一个现场规模的生物过滤器测试设施，使用溴作为保守的示踪剂。如果考虑了与周围土壤的横向交换，TTD理论可以很好地再现溴的穿透浓度。根据理论，在任何给定的时间，储存的水中有一半以上来自最近的风暴，其余的是倒数第二次风暴和更早的风暴的混合物。因此，关键的管理终点，如可归因于GSI的污染物处理积分，可能取决于这些系统储存和释放的水的不断演变的年龄分布。
In this study, we explore the use of unsteady transit time distribution (TTD) theory to model solute transport in biofilters, a popular form of nature‐based or “green” storm water infrastructure (GSI). TTD theory has the potential to address many unresolved challenges associated with predicting pollutant fate and transport through these systems, including unsteadiness in the water balance (time‐varying inflows, outflows, and storage), unsteadiness in pollutant loading, time‐dependent reactions, and scale‐up to GSI networks and urban catchments. From a solution to the unsteady age conservation equation under uniform sampling, we derive an explicit expression for solute breakthrough during and after one or more storm events. The solution is calibrated and validated with breakthrough data from 17 simulated storms at a field‐scale biofilter test facility in Southern California, using bromide as a conservative tracer. TTD theory closely reproduces bromide breakthrough concentrations, provided that lateral exchange with the surrounding soil is accounted for. At any given time, according to theory, more than half of the water in storage is from the most recent storm, while the rest is a mixture of penultimate and earlier storms. Thus, key management endpoints, such as the pollutant treatment credit attributable to GSI, are likely to depend on the evolving age distribution of water stored and released by these systems.