RFI - Att 3 - Engineers Response Letter

                                                                                                           ingeniir


       With reference to clause 3.2.2 of AS2890.1, there is no design requirement for this development to
       consider passing vehicles as this becomes a design benchmark where 30 or more movements (in and
       out) are expected within the peak hour, this development would not achieve 30 movements in a day
       so is not considered an appreciable design benchmark or consideration for this development.

Issue – Underground infrastructure
        The submitted documentation indicate that the proposed works is to be constructed in close
        proximity (above and adjacent) to existing Unitywater infrastructure and no relocation point
        to the existing water meter has been proposed. A statement from Unitywater approving the
        locality of the proposed works to their existing infrastructure has not been provided.

Information Required
      22. Provide an additional statement from a Unitywater representative authorising the
      locality of these works and the relocation of the water meter.

       In response to Item 22, the water meter can be upgraded to a trafficable lid by Unitywater private
       works. Build over sewer compliance if required will be documented as part of the building approval,
       the pergola structures previously shown in proximity to the sewer have been subsequently removed
       from the design.

Issue – Lawful point of discharge
        According to Council standards, the maximum discharge flow rate to a Lawful Point of
        Discharge is 25l/s in a 1% AEP event. The submitted documentation indicates that the
        maximum site discharge to each kerb adapter is 14l/s in a 5% AEP event. Council are
        concerned that the discharge flows from each kerb adapter in a 1% AEP event may create a
        worsening of existing drainage conditions and potential traffic hazards.

Information Required
      23. Provide additional detail considering the discharge rate in a 1% AEP event and
      demonstrating that this discharge rate will not create a worsening of conditions or potential
      creation of traffic hazards along Coral Tree Avenue if a 1% AEP event occurred. This detail
      must be prepared by a suitably qualified person (RPEQ – Registered Professional Engineer
      of Queensland). Provide a copy of the confirmation of payment for the Portable Long
      Service Levy (Q- Leave) for the project.

In response to item 23, the site discharge will be effectively non-worsening compared to the existing site
discharge rates. In accordance with IPWEAQ standard drawing RS-081 the site achieves 25L/s per discharge
point for a 5% AEP noting that RS-081 is for roof water kerb adapters and typical eaves gutters having a
design capacity for the 5% AEP event.

Site discharge rates are only expected to have a minor increase on the existing site discharge rates and
provide an improved drainage connection to the formal infrastructure being Coral Tree Avenue as the site
currently does not have any formalised discharge to the street.




                                               Ingeniir Pty Ltd | 221304-RFI-01
                ABN: 99 642 485 363 | PO Box 988 Maroochydore QLD 4558 | [email protected] | 0404157187
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