Cressbrook Dam is the Toowoomba Region’s key source of drinking water, servicing more than 180,000 residents. Designed by Farr Evrat & Associates from the early 1970s to 1980 and constructed from 1981 to 1983, the structure is a central core zoned earth-fill embankment with a concrete-lined spillway and chute on the left abutment. Its full storage capacity is 81,900 ML. The dam first reached full supply level in May 1989. 

Cressbrook Dam is located on Cressbrook Creek, approximately 15km downstream of Perseverance Dam and about 40km north-east of Toowoomba.

Cressbrook Dam is the Toowoomba Region’s key source of drinking water, servicing over 180,000 residents. Raw water from Cressbrook Dam is pumped to Council's Mt Kynoch Water Treatment Plant where it is treated and made safe for use. The treated water is then distributed to residents connected to the bulk water supply scheme. This will not change as part of the project.

The Cressbrook Dam Safety Improvement Project is located at Cressbrook Dam, about 40km from Toowoomba. The project will improve flood resilience and protect communities downstream in the Somerset Regional Council area during major flood events. It will also enable Council to comply with safety requirements set out in the Water Supply (Safety and Reliability) Act 2008.

The project, which is legislated by the State Government, will protect Queenslanders during major flood events and ensure the dam remains a reliable water supply for the Toowoomba Region. The Department of Regional Development, Manufacturing and Water has placed dam safety conditions on Toowoomba Regional Council, assessing the dam as "high risk" and requiring immediate improvement.

We have partnered with dam engineering specialists Seymour Whyte Constructions and SMEC Australia under a collaborative alliance model to deliver the project.

The project will widen the dam spillway to improve flood resilience and protect landholders downstream in the Somerset Regional Council area (Cressbrook Creek, including Toogoolawah). It will also improve dam monitoring, providing greater quality data inputs and control for downstream water operators such as Seqwater in their management of Somerset and Wivenhoe dams. The project will create local jobs during construction and encourage economic growth within Crows Nest and the broader Region.

The project is currently in the design phase. Early works, including surveying the dam wall, weirs and local roads and geotechnical investigations on and around the dam, are under way. These works are expected to be completed during the second half of 2024, weather and construction conditions permitting.

When we became aware of this project we began the necessary planning. Since then, we've needed to respond to unforeseen challenges such as significant flood events and the COVID pandemic, while continuing to work closely with the dam regulator to better understand the dam safety guidelines and how this will impact, not only our community, but those around us.

While we’ve been doing this detailed planning, we’ve continued to deliver critical infrastructure and essential services to our community such as new libraries, multiple sporting and community facilities, the Mt Kynoch Water Treatment Plant upgrade, reverse osmosis plant for Clifton, multiple water main renewals, road upgrades for the Toowoomba Bypass and other projects that ensure the Toowoomba Region is well-positioned for future growth.

We will always do what is in the best interests of our community. We are the first of 13 referable dams in Queensland to undertake this safety improvement project. We understand this is important legislation required to ensure our dam can continue to perform safely and protect downstream populations in the future.

This critical safety improvement project will reduce risks to people and property during major flood events. It will not increase the Region’s water supply. 

Dam safety assessments have been completed at Council's other dams Cooby and Perseverance. These assessments have concluded that no current improvements are needed at these locations. All dams in the Region are regularly monitored and inspected to ensure their safety, structural integrity and efficient operation within the bulk water supply scheme.

The project is the largest dam safety improvement undertaken by a Queensland local government to date and is expected to cost approximately $270 million.

We have budgeted $270 million for 2023/24 - 2025/26 and are currently seeking external funding to meet the total project cost. We submitted a business case requesting Queensland Government funding for the project July 2024. 

We have budgeted approximately $270 million from our Capital Works Program to fund the project in the event that external funding is not received. Using capital works funding may delay the delivery of other projects. However, critical projects to provide essential services will still be delivered. A financially sustainable Council is critical to ensuring the liveability of our Region now and into the future.

Main construction is expected to start in the second half of 2024.

Main construction is expected to be completed in late 2025, weather and construction conditions permitting. Some ancillary works may be required until the end of 2026.

The project will widen the existing spillway and raise the dam crest level. Construction work will include:

• upgrading access roads
• establishing site facilities, construction plant and laydown areas
• excavating rock for spillway widening works
• excavating and stockpiling dam wall materials
• importing new dam wall filter soils 
• reconstructing the dam wall
• constructing a concrete spillway
• restoring areas affected by construction activities.

Early works, including surveying the dam wall, weirs and local roads and geotechnical investigations on and around the dam, commenced during March 2024 and will continue until late 2024. Some improvements may be required to local roads to improve accessibility to the construction site at Cressbrook Dam. Early works are being completed from Monday to Saturday between 6am and 6pm. Local residents and visitors to the dam may notice increased traffic, noise, dust and vibration during this time.

Some access roads will be repaired and/or upgraded as part of the project to improve accessibility to the construction site at Cressbrook Dam. Affected residents will be notified of construction impacts prior to the start of construction.

The project will not affect access to water for Toowoomba Region residents who are connected to the bulk water supply scheme. There will be no reduction in the volume or quality of water available for residential or commercial use while the project is being constructed.

Water is one of our Region’s most precious resources and Council will ensure the project does not adversely affect water quality. Water will be drawn from the dam approximately 1000m away from the construction area. This water will be pumped to the Mt Kynoch water treatment plant to ensure that Council consistently provides high quality drinking water to the Region.

There will be some temporary disruptions including construction noise, dust and lighting from vehicles and machinery and increased traffic and changed traffic conditions on local access roads. The project team will work to minimise disruptions and will communicate regularly with the community about the project's progress and any potential impacts.

Construction activities are expected to cause increased dust. Dust management measures such as water spraying and road binding/dust suppressant agents will be in place to reduce dust.

Full security measures will be in place on site including CCTV cameras.

Dam safety must not be compromised during construction. We have partnered with dam engineering specialists Seymour Whyte and SMEC Australia to safely deliver this project.

Rock excavated as part of widening the spillway will be reused for constructing the embankment.

Early assessments have determined that minimal clearing is required. Access track designs have been carefully planned to minimise tree and vegetation clearing.

The project will create job opportunities for Toowoomba Region residents in various roles including the supply of goods construction, engineering, project management and administration. Council encourages local industry interested in supplying to the project to register an expression of interest through the project's ICN Gateway webpage.

Council encourages local industry interested in supplying to the project to register an expression of interest through the project's ICN Gateway webpage. For all other procurement or labour hire enquiries, please email damsafetyupgrades@tr.qld.gov.au or call 1800 737 123.

We expect the campground, boat ramps and walking trails will remain open and recreational activities, such as boating and fishing, will continue. We'll advise the community of any temporary disruptions to recreational activities at the dam.

To safely complete this project and minimise the risk of failure to the dam during construction, the construction crew needs safe access to parts of the dam currently underwater. Releasing water in a controlled way will enable the process to be managed safely and effectively. Detailed planning has been undertaken to minimise the time needed for the dam to be at a lower water level.

Water will be released gradually over a four-to-five-month period starting late 2024. This period may be extended if higher than expected rainfall occurs during this time.

Temporarily lowering the water level will not affect access to water for Toowoomba Region residents who are connected to the bulk water supply network. There will be no reduction in the volume or quality of water available for residential or commercial use during this time.

Council considered all practical options to utilise the water within the capacity of pumping infrastructure used to extract water from the dam. A report to Council in July 2024 found that it is not practically or financially feasible to re-use the water.

We will review the possible replacement of water released in the context of future weather conditions. This can be completed through using the Wivenhoe Pipeline.

We expect the campground, boat ramps and walking trails will remain open and recreational activities, such as boating and fishing, will continue. We will advise the community of any temporary disruptions to recreational activities at the dam during this time.

Regular updates will be provided through our website and social media channels. Community information sessions will be held in Toowoomba and Crows Nest ahead of the start of the main construction. We encourage the community to stay engaged and reach out to the project team on 131 872 or damsafetyupgrades@tr.qld.gov.au with any questions or concerns.