Swmp

Mitigating Measures

         •      Fall vehicles pavement areas towards landscaping areas and the bioretention bed.
         •      Implement management plan for landscaping propagation. Use stable organically bound
                fertilizers cultivated immediately prior to turf placement. Mulch over areas of exposed
                topsoil.
         •      Construction of silt fences during construction and maintained beyond completion of
                landscaping.
         •      Drain stormwater runoff through the Bio Basin.
         •      Capture roof runoff and store for re-use.

5.3.3    Proposed Treatment Measures
Implementing the water quality objectives for the site as mentioned above and to ensure that on-site
stormwater management facilities can be economically maintained, it was deemed the most appropriate
method for treatment is the inclusion of small grass swales and bio-retention basins. Roof and surface
runoff will be collected via an internal drainage network and directed to the on-site bio retention basins
prior to the lawful point of discharge.

5.3.4    Pollutant Modelling
The impact of the stormwater quality management strategy of runoff discharged from the site has been
assessed using the Pollutant Export Model, Model for Urban Stormwater Improvement
Conceptualisation (MUSIC).

For our model the proposed treatment train has been modelled: -

         1.     Roof water from buildings containing units 301-304, 401-404 will be collected by a 7kL
                rainwater re-use tank with an overflow to an onsite Bio retention basin, namely Bio-
                Retention Bed A (BR-A) located in the north-eastern corner of the site. The rainwater
                tank will be re-used for area landscaping irrigation only, to all common areas.
         2.     Roof water from buildings containing units 701-704 and the front portion of 601-602 will
                be collected by a 7kL rainwater re-use tank with overflow to the onsite Bio retention
                basin, namely Bio-Retention Bed B (BR-B) located in the South-eastern corner of the
                site. The rainwater tank will be re-used for landscaping irrigation only, to all common
                areas.
         3.     Surface runoff from hardstand and landscaping areas will be collected by numerous catch
                pits and pipes. The internal drainage network will then discharge into the onsite bio
                retention basins for treatment.



SCG Consulting Engineers                    Page 12                           SCG Ref: 33132(SWMP).RevB