Bray Park Weir Tidal Protection Project

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Alert for deployment of barrier to protect weir

There is a continuing risk that Bray Park Weir, which supplies raw water for the Tweed Shire, may be overtopped by tidal salt water during high tide and sea level anomaly events for the foreseeable future. Council monitors this risk and acts to protect the weir when necessary by installing concrete blocks to narrow the weir and temporarily raise the water level in the weir pool. The blocks are removed when the risk has passed. Residents who want to receive an email alert ahead of Council installing concrete blocks to temporarily protect the weir should register their name and email address by emailing wateradmin@tweed.nsw.gov.au (Subject: Weir Alert). Worst-case, Council will provide three hours’ notice of a temporary raising of the weir wall.

About

A combination of high tides plus an unforeseen sea level anomaly caused Bray Park Weir to be overtopped on the nights of the 21 and 22 August 2017.

The overtopping occurred at a time of low flow in the Tweed River and the consequence was salt water ingress into the Bray Park Weir pool.

The salt water ingress caused the raw water provided to the Bray Park Water Treatment Plant to be contaminated. Consequently, the contaminated salt water went into the Tweed drinking water supply.

At no time was it a risk to human health.

This issue will become worse over time with the impact of climate change and subsequent increases in sea levels.

This project seeks to identify and assess a range of options to reduce the risk of salt water ingress into Bray Park Weir both now and into the future and to identify a preferred option for Council’s consideration.

The preferred option may be a engineered or non-engineered solution or mix of solutions.

Alert for deployment of barrier to protect weir

There is a continuing risk that Bray Park Weir, which supplies raw water for the Tweed Shire, may be overtopped by tidal salt water during high tide and sea level anomaly events for the foreseeable future. Council monitors this risk and acts to protect the weir when necessary by installing concrete blocks to narrow the weir and temporarily raise the water level in the weir pool. The blocks are removed when the risk has passed. Residents who want to receive an email alert ahead of Council installing concrete blocks to temporarily protect the weir should register their name and email address by emailing wateradmin@tweed.nsw.gov.au (Subject: Weir Alert). Worst-case, Council will provide three hours’ notice of a temporary raising of the weir wall.

About

A combination of high tides plus an unforeseen sea level anomaly caused Bray Park Weir to be overtopped on the nights of the 21 and 22 August 2017.

The overtopping occurred at a time of low flow in the Tweed River and the consequence was salt water ingress into the Bray Park Weir pool.

The salt water ingress caused the raw water provided to the Bray Park Water Treatment Plant to be contaminated. Consequently, the contaminated salt water went into the Tweed drinking water supply.

At no time was it a risk to human health.

This issue will become worse over time with the impact of climate change and subsequent increases in sea levels.

This project seeks to identify and assess a range of options to reduce the risk of salt water ingress into Bray Park Weir both now and into the future and to identify a preferred option for Council’s consideration.

The preferred option may be a engineered or non-engineered solution or mix of solutions.

Guest Book

If you wish to make a comment or suggestion with respect to options to mitigate the risk of salt water inundation of the Bray Park Weir pool you can contact any member of the Project Reference Group or leave your feedback here.
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Large diameter pipes or ducts , angled on the upstream side , that closes as the tide rises . Heavy duty construction with deflectors on the upstream side for flood debris.

jasezam over 2 years ago

the most simple solution would be to construct a concrete wall on the existing weir to the required height tying into the banks and have 20mm aluminium gates fabricated to suite openings in wall with some sought of angled steel configuration on upstream side to allow debris from high volume flows to be washed over wall to stop damage to wall . which would not change existing water levels upstream.
d phillips

dphillips almost 3 years ago

Hi Mathuranatha Das, I would be very interested to hear some of the options you mention that would negate the need to raise the weir wall. Cheers

Simon Fitzpatrick almost 3 years ago

To stop salt water flowing up-steam over the weir does not necessarily mean the weir has to be raised [ an 18th Century solution ] In this day and age there are innumerable one way flow options that can prevent water flowing upstream without raising the height of the weir pool and its volume by trillions of litres .

Adding a huge volume of water to the permanent weir pool would greatly increase the frequency and severity of flooding

mathuranatha das almost 3 years ago

The circumstances that have caused the salt water ingress are all natural occurrences. I note there are many countries tackling this very subject.
Many indicate raising the levels of the levee would be helpful. I have looked at the idea of using sensors across the weir face which would at the first detection of salt water would immediately cause the raising of barriers to exclude the salt water.
Another option is to install permanent barriers to ensure the preclusion of any back flow of water or inundation by salt water.

Mazza almost 3 years ago