Compiled Reference Document - MCU25/0020 (As Published)

ADG Consulting Pty Ltd

 

— Installation of additional sedimentation tanks to provide increased residence time and assist with
the retention of precipitated iron hydroxides, other heavy metals and/or suspended sediments.

— Installation of additional flocculant and/or coagulant dosing systems to assist in precipitation of
suspended sediments and/or heavy metals.

— Installation of activated carbon filtration or other fine media filtration to retain suspended
sediments and/or heavy metals.

— Install a floating sediment curtain/s around the stormwater termination point in the receiving
waterway to prevent unsightly plumes and contain sediment and/or heavy metals for periodic
removal (subject to approval by Noose Shire Council).

— Preventive and corrective actions shall be taken in the event that groundwater monitoring
observations indicate that unexpected groundwater contamination has been encountered during
dewatering. The most appropriate action(s) shall be dependent on the stage of construction and
risk of adverse impacts to groundwater users and the receiving environment.

— Any modification to the dewatering system and pumping rates shall be in consultation with a
suitably qualified scientist/geotechnical/engineer.

— Following heavy rainfall all ponded surfaces waters are to meet discharge criteria (Table 3) prior to
offsite discharge. Where discharge criteria not met, Site Manager to obtain approval from
Dewatering Contractor regarding treating surface waters with treatment gear before offsite
discharge.

— Pumping systems and shoring works to be maintained in fit for purpose state by Dewatering
Contractor and/or shoring contractor. In the event that dewatering equipment has failed and is
likely to cause a significant impact on the environment, or surrounding properties (i.e. flooding) the
Dewatering Contractor is to be contacted immediately. The Principal Contractor, in consultation
with the Dewatering Contractor shall be responsible in rectifying the failure in a practicable time
frame to minimise potential impacts.

— Equipment, spare parts, materials and tools necessary to manage aspects of the system/s which
present a high risk of significant impacts in the event of failure (if any) shall be readily available.

— Construction vibrations could potentially cause settlement in the loose upper level sands, thereby
damaging nearby structures founded in these strata. Prior to commencement of construction on
site (including staged works), it is recommended that a detailed dilapidation survey be undertaken
to establish the condition of all existing adjacent structures, roads and services.

 

ADG1786.25 Dewatering Management Plan_Rev1_07.10.25 Page 17