Australian Water Management Review Vol. 1 2014 | Page 16

ground pumping station, which transfers the dilute
wastewater to the storage tank. The tank is emptied
via a 150m long, 800mm diameter gravity pipe in
Sydenham Road from flow control valves at the tank
outlet. A manual discharge system has also been
provided which would allow the tank to be emptied
in the case of a complete system blockage (up to
and including the flow control valves) or failure in
the normal method of tank discharge.
The tank is equipped with an automated flushing
system, which uses the rainwater captured from the
roof. A rainwater storage tank of 540m3 capacity
along the northern face of the storage tank is
provided to store the rainwater. The flushing system
provides jets of water, which clean the floor after each
operation of the tank and minimises odour generation.
The Project

The enclosed roof:

The project involves the provision of a new overflow
storage facility to reduce the frequency of operation
of overflows in Chard Road, Brookvale, Winbourne
Road, Brookvale, Abbott Road, Curl Curl and Ada
Avenue, Curl Curl. The tank temporarily stores excess
wastewater diverted from the Narrabeen Submain
during a storm event which is released back to the
Submain after the storm event.

• Contains any odours generated during nonoperating and operating periods

In June 2010, Sydney Water procured a 4,700 m2 site
for the Northern Beaches Storage Project within the
Brookvale industrial area, providing sufficient area for
a storage tank and associated facilities. Construction
of a 2400 m2 rectangular, above ground, reinforced
concrete storage tank of 18 million litres capacity
was then undertaken. The storage tank is as high as
a two storey industrial building and has a reinforced
concrete roof.
10 | Australian water man age m e nt re v ie w

• Provides a catchment for rainwater collection
• Excludes birds and vermin and other unwanted
contamination
• Assists the walls in supporting the hydrostatic
loads
• Provides a platform for other items, such as
ventilation ducts, and access hatches
• Minimises the risk of unauthorised access to the
tank interior
A 150m long, 1200mm diameter inlet pipe in
Chard Road conveys the overflows to a below

The tank is provided with an architecturally design
façade to enhance its appearance.
The storage tank is equipped with analogue level
sensors, which will stop the pumps on detection
of maximum design water level of 21 m Australian
Height Datum. An Alarm Top Water Level switch
will provide an emergency shutdown signal for the
pumps and an alarm if the analogue system fails.
Outlet flows will be monitored by an electromagnetic
flow meter (with empty pipe detector and forced
0 output function) housed in the control valve
chamber upstream of the control valves.
It is expected that the tank will completely fill about
twice a year on average and receive an average of 7
overflows per year.