Burrendong curtain install near complete, trial to resume

Burrendong curtain install near complete, trial to resume

10 August 2018

Installation of the Burrendong Dam cold water pollution curtain has reached the final stage, with work to be completed in mid-August, allowing the trial to control downstream water temperatures to resume.

WaterNSW has undertaken extensive work to engineer a revised design for the curtain, which has been progressively installed on Burrendong Dam’s intake tower over recent months.

The reinstallation is the culmination of extensive repairs and follows the replacement of manufactured components deep below the water surface.

Burrendong’s storage is less than 35% of capacity so thermal stratification – that is, warmer water concentrating on the surface with progressively colder water at depth – is currently not occurring.

The full trial of both the new design and the structure’s impact on downstream riverine habitat will recommence when thermal stratification occurs.

Following the curtain’s malfunction in November 2016, WaterNSW engineers conducted an exhaustive review of the incident and worked to redesign the curtain.

New guidewire connections and rollers have been manufactured to improve the device’s reliability, according to WaterNSW Executive Manager Asset Solutions and Delivery, Andrew George.

“The redesign process demonstrates the capability both of our engineering expertise and the local businesses engaged to manufacture the new connections and rollers”, Mr George said.

“WaterNSW will shortly resume monitoring and testing of the curtain and assess its potential as a long-term option for managing cold water releases once it has been commissioned and the dam storage level rises.”

Instrumentation has been installed to monitor the performance of the new design and existing temperature loggers from Wellington to Warren will provide data at half hour intervals to monitor surface water temperatures further downstream of the dam.

For further information read about the Burrendong cold water pollution project.

Background:

The Burrendong Dam cold water pollution curtain was constructed and commissioned in 2014 as a trial aimed at mitigating the effects of cold water pollution that occur when cold water from the bottom of the dam storage is released downstream into the Macquarie River.

The cold water can have a negative impact on the aquatic food chain and breeding of native fish species.

The project involves a floating-curtain temperature control structure around the intake tower at Burrendong Dam.

The flexible structure sits just below the water level to ensure warmer, surface water is released from the dam valve, rather than colder water from the depth of the storage.

The curtain can move up and down with the water level to function regardless of the storage level of the dam.

In late 2017 specialist deep-water divers were brought in to examine coupling points for the curtain, which were at the time 35 metres beneath the surface of the dam storage, at the foot of the intake tower.

The anchor points for the cables securing the curtain failed during the extraordinary inflows into Burrendong Dam during the rain event in Winter/Spring 2016.

The investigation phase also involved re-engineering the curtain itself and revising its design to improve its strength and durability.

Contact: Tony Webber

Phone: 0428 613 478

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