Reference Document MCU22-0102 Stormwater Management Plan

          4.4.1.      SPELBasin
The SPELBasin is a SQIDEP approved modular Bioretention System, refer to Appendix B for
further information and below in Figure 6 for a table of the treatment efficiencies provided by
this unit. Its size and capacity make it an ideal solution for stormwater treatment trains that
require a high pollutant reduction in a small footprint. It can be used in place of standard catch
basin structures, rain gardens, bioretention cells and media filters. As a self-contained treatment
train, it incorporates the following treatment components: screening, hydrodynamic separation,
media filtration and a bioretention filter. Given the subject site characteristics, ie: existing and
proposed site levels/contours, locations of the proposed landscaped areas, location of the
proposed legal point of discharge, location and depth of the existing sewer pipe traversing
through the site etc… it is not possible to install a non-proprietary raingarden or bioretention
system in the landscaped areas. As this product is a self-contained SQIDEP approved treatment
module, can be built into the landscaped area; it is the preferred system to be adopted on this
particular site. It will also make future maintenance easier due to the modular chambers of the
design making it simple to maintain given the surrounding driveway and footpath areas.




Figure 6; SPELBasin product features.
The SPELBasin is easily integrated within the proposed landscaped area and has been designed
to have a high-flow by-pass pipe for larger storm events. The SPELBasin will be planted with
specific plant species that thrive in Bioretention environments- as listed in the SPEL Technical
Design Guidelines (Appendix B, brochure page 7). Maintenance for the above unit shall be in
accordance with SPEL Stormwater requirements.
The SPELBasin has the following advantages over a traditional Bioretention Garden:
    The SPELBasin is a SQIDEP verified product that is a bioretention treatment devise that
      has four main differences to a typical designed bioretention system, including:
      1. The use of a controlled, selected media blend,
      2. Maintains horizontal flow through the media column unlike a traditional bioretention
         system which is reliant on surface and downward flow, which will generally blind due
         to sediment loadings,
      3. An enhanced Media lifespan of between 12-15years, with minimal maintenance.
      4. The unit has been independently tested and has verified reduction targets that are
         SQIDEP verified as per the attached report (in Appendix B).
    The SPELBasin also has consistent guaranteed stormwater quality results which surpasses
      that of a typical Bioretention garden.




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