Swmp

                                  Table 6.1 - Adopted (IL) and (CL) Values

                                     AREAS                 (IL)           (CL)
                                                          (mm)           (mm/hr)

                                   Impervious               1              0

                                     Pervious              27              2.6



Design ARR 2019 storms for Noosaville have been added into DRAINS using data obtained from the
ARR 2019 Data Hub accompanied with IFD rainfall depths from the Bureau of Meteorology (BOM)
website

Times of concentration (Tc) were calculated as defined in QUDM 2017 using a combination of standard
inlet time & overland sheet flow time. Table 6.2 displays the Adopted time of Concentrations.

                                             Table 6.2 – Tc Values

                               STATE                         (Tc) (mins)

                           Pre Development                           15

                           Post Development                          6




6.1.1     Existing Catchments
The existing site consists of 4 Lots containing residential dwelling on each, detached sheds & landscaped
ground areas. The existing surface generally falls in a eastern direction towards the rear boundary. Roof
runoff from existing dwellings appears to be a mixture of discharging directly to ground level & via kerb
adaptors to Headland Drive.

The total impervious area has been estimated using the detailed site survey and was found approximately
19% Impervious Area (Fi = 0.19) which equates to approximately 1200m2.

The existing site catchment is as follows.

    -   Area – 0.6326 Ha
    -   Tc – 15 mins
    -   Fraction Impervious (Fi) – 0.19

Peak flow rates for the median design storm for the existing site are given in Table 6.3




SCG Consulting Engineers                     Page 15                               SCG Ref: 33132(SWMP)