Attachment 4 - Engineering Report · MCU18/0015

               6.3.3 Catchment Details

               Please refer to Table 6.3.3a for details of the post developed catchments
               considered in stormwater quantity calculations. A total of seventeen (17)
               sub-catchments were analysed in order to determine a single suitably
               sized tank/orifice-outlet configuration. A 5.0kL tank combined with a
               50mm low flow orifice was found to adequately control discharge for all
               townhouse sub-catchments examined.

               A 5.0kL tank combined with a 55mm low flow orifice was found to
               adequately control discharge for the proposed residential lot.

               Table 6.3.3a Catchment and Tank Details

         Town     Roof Area Road Area    Total    Tank Vol   Orifice   Stage
         House      (m²)       (m²)     Area (m²)   (KL)    Dia (mm) Depth (mm)
            1            175    134.25     309.25       5.0        50       1913
            2            165    134.25     299.25       5.0        50       1754
            3            165    134.25     299.25       5.0        50       1754
            4            165    134.25     299.25       5.0        50       1754
            5            175    134.25     309.25       5.0        50       1913
            6            175    134.25     309.25       5.0        50       1913
            7            175    134.25     309.25       5.0        50       1913
            8            175    134.25     309.25       5.0        50       1913
            9            175    134.25     309.25       5.0        50       1913
           10            175    134.25     309.25       5.0        50       1913
           11            160    134.25     294.25       5.0        50       1675
           12            160    134.25     294.25       5.0        50       1675
           13            160     67.00     227.00       5.0        50       1675
           14            160     67.00     227.00       5.0        50       1675
           15            160     63.50     223.50       5.0        50       1675
           16            160     63.50     223.50       5.0        50       1675
        Res Lot         200*      0.00       200*       5.0        55       1927
       *Assumed roof area. To be confirmed when development plans are made
       available.

               Please note that roof/driveway catchment details are based on
               preliminary architectural plans and may be subject to refinement at the
               OPW design stage.




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C5756/17/Engineering Report - 27 Attunga Heights, Noosa Heads          4
January 2017   JW/jl