Andrew Evans, Michael Cawood, Jonathon Reid
Eildon Dam, Goulburn Weir and Waranga Basin in Victoria are owned and managed by Goulburn-Murray Water (G-MW). Eildon Dam and Goulburn Weir are situated on the Goulburn River, while Waranga Basin is an offstream storage supplied from Goulburn Weir.
In November 2004 a dam safety emergency exercise involving the establishment of a central Emergency Coordination Centre at Tatura as well as Emergency Operations Centres at each of these three dam sites was conducted. The exercise presented a variety of emergency situations in stepped time increments, including earthquake, mechanical failure, a hazardous material spill and a terrorism related incident. External agencies were not involved.
The exercise was part of an ongoing G-MW program designed to test and improve dam safety emergency planning and response systems for all of G-MW’s dams and highlighted areas where procedures, situational management and communications can be enhanced.
Outcomes aimed for in G-MW’s program are improvement in Dam Safety Emergency Plans and internal communications, together with clarification of roles, responsibilities and capabilities.
The valuable experiences learned from this dam safety emergency exercise and plans for a larger scale exercise involving other emergency management agencies will be shared with others through this paper.
Brian Simmons, Glen Hobbs, S Muralitharan, Udaya Peeligama
Warragamba Dam supplies up to 80% of Sydney’s water needs and is currently undergoing a range of major infrastructure upgrades. The outlet works upgrade is one of these projects. The outlet works of the dam were constructed in the 1950s and consisted of four 2100mm pipes with isolating gate valves and needle control valves feeding two large aboveground pipelines running 27 kilometres east to Prospect Reservoir in Sydney’s western suburbs.
In the 1990s the then dam owner (Sydney Water) undertook a detailed and extensive risk analysis of the outlet works. The study resulted in a recommendation to remove the existing valves and replace them with a combination of emergency closure (guard) valves and isolating valves. Under the Sydney Catchment Authority (the present dam owner) work subsequently proceeded in 2004 as a design and construct contract with all aspects of construction and water supply risks identified. Stringent controls were developed and placed on work programs and pipeline shutdowns to ensure the safety of all involved and the integrity of the supply to Sydney.
The four outlets required eight large valves, which were manufactured in Germany and were required to meet stringent operational requirements.At the time of writing three of the four outlets have been successfully upgraded and commissioned.Work has commenced on upgrading the fourth outlet, which is due for completion by the time of the conference, approximately 20 months ahead of schedule.
This paper discusses the project from the initiation of the risk analysis study, through the consideration of options, development of the contract, and the supply, installation and commissioning of the large valves and pipe work. It highlights the role of risk assessment in selection of the preferred option and addresses some of the engineering challenges faced during the project.
Peter Hill, Kristen Sih, Rory Nathan, Phillip Jordan
This paper presents a number of innovative hydrologic investigations undertaken for the recent detailed design of upgrades for Ross River Dam in North Queensland. A key issue for estimating extreme floods in the tropics is the estimation of flood events of long critical durations. The implication is that there is an increased focus on estimating the correct volume (not only the peakflow). This paper describes the regional analysis of flow volumes that was used to validate the estimated flood volumes.
Another issue of considerable importance is the assumed relationship between inflows and initial reservoir level. The analyses described in this paper showed that inflows are independent of reservoir levels for the more frequent events but for more extreme events they are correlated. This has important implication on how the initial reservoir level is incorporated in the hydrologic analysis. The final aspect covered by the paper is the derivation of seasonal flood frequency curves. This is particularly important given the highly seasonal nature of rainfalls in the tropics and the results are important for assessing risks during construction and scheduling the upgrade works
The Ross River Dam was first commissioned in 1974 and raised in 1976. The 8200 m long
embankment was not fitted with chimney filters and has suffered extensive desiccation cracking since it was raised. A significant component of the dam upgrade is the retrofitting of filter zones to ensure the embankment meets current dam safety guidelines.
This paper describes the process of investigation of the existing desiccation cracks and the use of Hole Erosion Tests (HET) and No Erosion Filter (NEF) tests to validate the design of the retrofitted filter. A significant challenge in the design is to provide a cost effective solution given the 7500 m length of embankment requiring treatment. Assessment of flow rates within cracks and expected piping erosion along the cracks was used to assess the required drainage capacity. This assessment of expected flow capacity allowed the deletion of the coarse filter in the design reducing the filter requirement from a triple filter to a single fine filter. Results of this assessment were incorporated into the Risk Assessment based design validation process.
This paper outlines how Grampians Wimmera Mallee Water (trading as GWMWater) and its consultants managed the upgrading of Bellfield dam’s 43m high, reinforced concrete dry outlet tower and discharge facilities. The upgrading included improvements to operations, the provision of safe person and materials access into the tower and its 1200 mm diameter steel penstock, anchoring the tower with post tensioned cable anchors to resist seismic loads, refurbishing a 1200 mm butterfly valve and penstock corrosion assessments and repair.
Prior to the upgrading, access to all areas was difficult and unsafe to some areas. In particular no provision had been made during the original construction for butterfly valve removal or safe access into vertical sections of the penstock. Overcoming these deficiencies required considerable survey, detailed movement planning and attention to detail.
Stuart Macnish, Nikki Bennett
The $70 million upgrade of Wivenhoe Dam is being undertaken by the Wivenhoe Alliance, in close
proximity to the town of Fernvale, Queensland. As part of the Alliance’s commitment to delivering positive outcomes for the local community, it was decided part way through the project, to commit to delivering a ‘signature’ community legacy project. The team brainstormed a range of options and a decision-making matrix was used to choose the project that would best meet its objectives.
A partnership has been formed between the Alliance, Esk Shire Council and SEQWater to deliver a
master-planned project which incorporates elements such as a community information/service facility,upgrade of Fernvale Memorial Park, streetscape enhancements, improved parking and installation of shelters along the adjacent rail trail. These major partners, together with representatives of the local community, constitute the steering committee, which oversees planning of the project.
The project aims to encourage visitors to the area, to provide improved amenity and sense of pride for the region, and in turn encourage strong relationships for SEQWater in the area in which they operate. Due to tight time frames the partnership is managing the fund raising activities, community consultation and design processes in parallel.
This paper discusses the process by which the Alliance was able to deliver this remarkable project, within a short timeframe. It also discusses how the local community has been involved and the benefits, which have resulted.