20230025_RECOR_MCU Engineers Letter_20.12.24

            The bioretention basins will be designed in accordance with Water By Design’s Bioretention
            Technical Design Guidelines (2014). Planting will be provided in accordance with Council’s
            requirements.

            Atlan Basin

            The Atlan Basin is an advanced prefabricated, compact and self-contained stormwater
            treatment system that provides similar treatment to a bioretention area.

            Preliminary sizing was requested from Atlan for the proposed Atlan Basin. Atlan undertake
            their own in-house MUSIC modelling and provide recommended sizing for their products
            to meet the required water quality objectives. Attached in Appendix A is a drawing of the
            recommended unit. Below is a typical detail of the proposed unit.




                                             Figure 2 -Atlan Basin Typical Detail

            Atlan have recommended that their Stormsack product is installed to all inlet pits upstream
            of the Atlan Basin to collect Gross Pollutants at source.

            The Atlan Basin is a SQIDEP certified device having treatment efficiency that meets the SPP
            water quality objectives. Below is output provided by Atlan from their MUSIC model for this
            particular site. The modelling indicates that the proposed unit meets the water quality
            objectives for the site.




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