Applicant's Response to Council's Information Request

Guideline (May 2017). Here the applicant has proposed for stormwater to be treated via a buried
proprietary system, which does not appear to use natural processes and materials.

Information Required

15. Demonstrate how the buried proprietary system is using natural processes and materials that
    enhance biodiversity and landscape benefits as required by PO7. Where a conventional
    vegetated bioretention system is proposed in lieu of the current design to meet PO7,
    demonstrate that the bio-basin is integrated with the development consistent with Healthy
    Land and Waters Bioretention Basins: Bioretention Technical Design Guidelines (October
     2014), without the need for retaining walls.

Applicant’s Response
As the proposed proprietary system will be buried the landscape plans show that there is an opportunity
to landscape the area above it. This approach will ensure that the proposed system does not detract
from the attractive landscape setting proposed for the development.

The documents attached to this letter also include an indicative bio retention system to illustrate the
potential impacts that this type of solution could have on the development. In our view the indicative
outcome is not desirable and ultimately, as it would have to include retaining walls, would not comply
with Council’s standards for this type of basin. The indicative outcome is driven by the need for the
proposed development to have level surfaces throughout in order to create a safe environment for
residents who will all have high physical support needs. As a result, alterations to natural surface levels
are required.

Overall, the applicant firmly believes that the proposed proprietary system is the best outcome for the
site and will ensure that is provides a high quality design that is more in keeping with the local context
of the site.

Given the importance of this issue to the overall design outcome and the critical need for the
development to provide a safe and accessible environment for future residents, we would value the
opportunity to discuss the alternative stormwater treatment outcomes in more detail.


Council Issue
PO8 of the Water Quality and Drainage Code requires Water quality treatment infrastructure to be
dedicated as public assets are proven to be suitable for its use and of a cost effective and efficient
standard. This information request is included in relation to the fact that the development is proposed
on land designated for community use and therefore understood intended to provide public benefit.
The performance of proprietary water quality treatment infrastructure is dependent on ongoing
maintenance. The ongoing maintenance costs associated with the proprietary water quality treatment
infrastructure are unknown.

Information Required

16. Where a proprietary stormwater quality treatment system is proposed, provide a lifecycle
    costing assessment for the proposed treatment train in comparison to alternative treatment
    measures pursuant to AS/NZS4536:1999. In the assessment include the entire water quality
    treatment train system including replacement costs of asset parts.

Applicant’s Response
A lifestyle costing prepared by SPEL is included in the supporting documents attached to this letter.

Please note that as the application seeks approval for a private development, the applicant is not
intending to hand the proposed stormwater treatment infrastructure over to Council. As a result, the
applicant will be responsible for the on-going upkeep and maintenance of the system and is happy to
provide a letter to Council to confirm this commitment.