Geotechnical Solutions has not demonstrated that the soil into which infiltration is proposed are suitable for this purpose.
The infiltration rates derived by Geotechnical Solutions using international standard D3385 – 18 are much higher than the threshold identified in international standard D3385 – 18 above which results are potentially unreliable. The reliability of the results obtained by Geotechnical Solutions is questionable.
The infiltration test used by Geotechnical Solutions, international standard D3385 – 18, does not provide a saturated hydraulic conductivity value. A saturated hydraulic conductivity value is needed to size the infiltration facility.
Tatersal Lander have wrongly assumed that the infiltration values provided by Geotechnical Solutions are hydraulic conductivity values and have arrived at a hydraulic conductivity value for sizing the infiltration facility based on this assumption. The infiltration facility will therefore be wrong.
The outcome of the above issues is that a credible stormwater disposal facility has not been proposed for the development. Concern is raised that this will result in the eventual stormwater proposal for the site not being subject to public consultation.
If I can attach International Standard to my submission I will. Otherwise the Standard and other documents referred to in this submission, Australian Runoff Quality and WSUD: Basic procedures for source control. A Handbook of Australian Practice, can be downloaded for free by searching in Google. This is a summary of my comments; my complete comment is provided as an attachment.

As long-term property owners in Hawks Nest, we appreciate the need for housing development. Long-term rentals are in short supply, and people working in the area often cannot live close by. However, the Sanderling Ave development is not the answer and we heartily object to it. It is not in keeping with the rest of Hawks Nest realty in terms of its height (particularly in proximity to the beach) and the sheer magnitude of it in terms of the number of dwellings. It will also do nothing to reduce rental pressure as it is clearly marketed as an upscale development - not suited to your average working family, only for those who will likely buy to rent dwellings out as AirBnBs or holiday homes. Please do not approve this development as is - either reduce the height to a maximum of two stories and reduce the number of dwellings, or locate it somewhere different and allow for some social and affordable housing options within.

We request that the application be refused. See our attached document for our detailed reasoning.

See attached Objection