HYDROLOGIC PERFORMANCE OF A BIORETENTION BASIN AFFECTED BY GROUNDWATER INTRUSION

    Research output: Chapter in Book/Conference paperConference paper

    Abstract

    Bioretention basins, at-source control structural elements for stormflow control and water quality improvement,
    have become common Best Management Practices in Water Sensitive Urban Design for stormwater
    management. New urbanization in Perth, Western Australia (WA) occurs in areas prone to perched
    groundwater capable of intersecting bioretention systems during the rainy season and its impact on the
    hydrologic performance and nutrient removal capacity of structural elements is unknown. This work presents
    results of an intensive monitoring program aimed to assess the hydrologic performances of a 0.35 m depth -
    370 m3 capacity bioretention basin affected by high groundwater. Continuous records of hydrometric and
    passive tracer (electrical conductivity) data at inflow, surface water storage, and outflow stations were
    collected for a year in 2015 to quantify the water balance and to identify the timing of the groundwater
    intrusion and its effect on the hydrologic performance of the bioretention basin. Results from hydrometric and
    the passive tracer data indicated that groundwater interactions impacted the performance for a period of 50
    days from mid-August to late-September affecting volume control and to a less extend peak flow reduction.
    The bioretention basin achieved outflow/inflow volumetric ratio (%) of 17% and 44% for small and minor rain
    events in absence of groundwater interactions but increased to 73% (27% reduction) when groundwater
    intercepted the underdrain outflow pipes. Hydrologic performance for peak flow reduction was achieved at
    98% for small events and 74% and 79% for minor events with and without groundwater interactions,
    respectively. A transition stage in the bioretention basin functioning was identified from the interplay of inflow
    peaks, groundwater dynamics and water losses (exfiltration). The study showed and concluded on the need to
    properly identify groundwater interactions and their implications on nutrient loading and removal assessment
    that are often neglected.
    Original languageEnglish
    Title of host publicationProceedings of the 37th IAHR World Congress
    EditorsAminuddin Ab. Ghani, Ngai Weng Chan, Junaidah Ariffin, Ahmad Khairi Abd Wahab, Sobri Harun, Amir Hashim Mohamad Kassim, Othman Karim
    Place of PublicationSpain
    PublisherIAHR International Association of Hydraulic Engineering and Research
    Pages4061-4069
    Number of pages9
    Publication statusPublished - Aug 2017
    Event37th IAHR World Congress - Kuala Lumpur, Malaysia
    Duration: 13 Aug 201718 Aug 2017

    Conference

    Conference37th IAHR World Congress
    Abbreviated titleIAHR 2017
    CountryMalaysia
    CityKuala Lumpur
    Period13/08/1718/08/17

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