Impact of Wind on Stormwater Pond Particulate Removal

Stormwater ponds provide cost and space-efficient treatment of urban runoff via gravitational settling. The goal of this paper was to quantify different mechanisms by which wind can affect the particle removal efficiency of a shallow retention pond. An analytical bulk model was developed and validat...

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Bibliographic Details
Published in:Journal of Environmental Engineering
Main Author: Andradóttir, Hrund
Other Authors: Umhverfis- og byggingarverkfræðideild (HÍ), Faculty of Civil and Environmental Engineering (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
Format: Article in Journal/Newspaper
Language:English
Published: American Society of Civil Engineers (ASCE) 2017
Subjects:
Particle size
Resuspension
Settling
Short-circuiting
Stormwater pond
Treatment efficiency
Wash loads
Wind mixing
Tjarnir
Umhverfisverkfræði
Vindar
Esther
Iceland
Online Access:https://hdl.handle.net/20.500.11815/581
https://doi.org/10.1061/(ASCE)EE.1943-7870.0001221
Description
Summary:Stormwater ponds provide cost and space-efficient treatment of urban runoff via gravitational settling. The goal of this paper was to quantify different mechanisms by which wind can affect the particle removal efficiency of a shallow retention pond. An analytical bulk model was developed and validated numerically against total suspended solids (TSS) measurements in a small (0.3 ha), optimally designed oval pond during four runoff events with 7–11 m/s winds. Simulations highlighted wind as an effective mixing mechanism, lowering the removal of medium silt particles by 10–20% from ideal plug flow, and severely constraining the removal of small clay and silt particles (<6 μm). Initial background concentrations of <12 mg/L TSS were positively correlated with wind speed 5 h prior to the event, indicative of localized wind resuspension. A widespread remobilization of bed sediments was found unlikely in a 1.7-m deep, 112-m fetch pond. A stirred reactor with 60% effective volume is proposed as a first order tool to assess the treatment performance of ideally structured ponds in areas with strong, unobstructed winds. This work was funded by the University of Iceland Research Fund. The Icelandic Meteorological Office is thanked for data and equipment for PSD assessment. Gudbjörg Esther Vollertsen is thanked for field data collection. Professor Lars Bengtsson at Lund Technical University is thanked for his comments on the manuscript. Peer Reviewed

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