Retarding Basin Fundamentals (April 2013) – MODULE 1 TO 4
Retarding basins are becoming increasingly important elements in urban flood planning throughout Australia but it is evident that many basins have not been implemented in line with modern day “risk management” approaches. Accordingly, as part of its Professional Development program, and in advance of its proposed Guideline on Retarding Basins due out in 2014, the Australian National Committee on Large Dams (ANCOLD) is planning a series of seminars across Australia on Retarding Basin Fundamentals. The seminars are being provided to assist basin owners, and their professional staff and advisors, to plan, implement and operate their basins in a safe and effective manner consistent with various Government and “duty of care” obligations.
The one day seminars are being presented by leading dam safety and risk management professionals including:
Richard Rodd- dams consultant with over 40 years experience in dam and basin design, construction, operation and maintenance.
Kelly Maslin – dams consultant with over 15 years experience in dams and risk management.
Norm Himsley – dams consultant and member of NSW Dam Safety Committee with over 40 years experience in dam and basin design, construction, operation and maintenance.
Includes access to the following videos:
$60.00 - $80.00
Dam Safety Emergency Planning (June 2014) – MODULES 1 TO 5 (FULL COURSE)
COURSE OBJECTIVES AND OUTLINE
This short course is designed to provide a comprehensive understanding of all aspects of dam safety emergency planning including developing, using, exercising and reviewing dam safety emergency plans.
It will begin by briefly reaffirming why dam safety emergency plans are needed and then provide a high level overview of legislative requirements for each State.
Critical elements of dam safety emergency planning and plans will be presented in detail. This will be followed by guidance on how to develop and document dam safety emergency plans.
The seminar also includes modules on training operators and emergency responders in the use of dam safety emergency plans and exercising them so that everyone is confident that the plan will work in a genuine emergency.
The presenters will use examples from their experience to illustrate all aspects of dam safety emergency planning and there will be opportunities for delegates to ask questions and share their experiences throughout the day.
Stephen Newman, Kelly Maslin
Lake Bellfield is a reserve storage for the Wimmera Mallee Water (WMW) Stock and Domestic System in North Western Victoria, constructed between 1963 and 1967. The dam is located on Fyans Creek approximately 3 km upstream from Halls Gap in an area of high tourist value and is rated in the Extreme category under ANCOLD guidelines. The dam consists of an earth and rockfill embankment 745 m long with a maximum height of 57 metres and retains a reservoir with a storage capacity of 78,500 ML.
Previous studies and a subsequent physical model study confirmed that the existing spillway does not meet the requirements of the current ANCOLD guidelines. The current flood capacity is approximately 40% of the Probable Maximum Flood. A range of potential upgrade options to pass the PMF were evaluated with a 1.9 metre composite earthfill and downstream concrete parapet wall raise in combination with spillway lowering of 3.4 metres selected. Construction of this option was completed in early 2003.
This paper describes the key features of the investigation and design including:
Sean Ladiges, Robert Wark, Richard Rodd
The use of permanent, load-monitorable post-tensioned, anchors for dam projects has been in place for approximately 35 years in Australia. Since then, over 30 large Australian dams have been strengthened using this technology, including the world record for anchor length (142 m – Canning Dam, WA) and size (91×15.7 mm strands – Wellington Dam, WA and Catugunya Dam, TAS).
In order to achieve the design life of 100 years expected of these anchors, an ongoing program of monitoring, testing and maintenance is required, to identify and rectify the initiation of corrosion or loss of pre-stress. Guidance for maintenance and testing regime for post-tensioned anchors in dams is provided in the ANCOLD Guidelines on Dam Safety Management (2003). The various conditions which may affect the performance of the anchor with time, such as anchor type, ground condition and loading fluctuations are not covered in the Guideline.
This paper reviews the implementation and results of anchor monitoring programs by Australian dam owners. The first part of this paper provides a summary of the testing and monitoring programs currently being implemented. The second part of the paper reviews the aggregated anchor load test results from a number of Australian dam owners, and identifies trends in anchor response over time following installation.
The paper aims to assess whether the recommended anchor testing regime proposed in ANCOLD (2003) is appropriate and cost effective, using evidence from recent load test data which has become available following the writing of the guideline. The lessons learnt from anchor maintenance programs will also be discussed.
Peter Hill, David Stephens, Kelly Maslin, Rachel Brown, Simon Lang, and Chriselyn Meneses
There has been a growing awareness of the potential dam safety risks associated with hydraulic structures in urban environments such as retarding basins, water quality detention basins and recreational lakes. This has required estimates of rare and extreme floods for urban catchments and there are a number of important characteristics of urban catchments which distinguish them from rural catchments such as impervious areas, lack of streamflow data, blockage of structures and complex hydraulics. This paper describes the key considerations for flood estimation in urban catchments and draws examples from a number of current flood studies for urban catchments in Canberra.
Barton Maher, Richard Rodd
Changes to the estimation of extreme rainfall events resulted in significant increases in the estimates of the PMF since the original design of Wivenhoe Dam. To upgrade the dam to meet these new requirements, SEQWater (owner and operator) formed an Alliance with Leighton Contractors, Coffey Geosciences, MWH and the NSW Department of Commerce.
The option selected for the upgrade works included the construction of a new secondary spillway, upgrade of the existing gravity section, radial-gated spillway, and strengthening of the dam crest.
Value management was key throughout the project ensuring the Alliance was continually looking to
improve practices, increase cost-effectiveness and create innovative solutions for design elements of the project.
On numerous occasions when the design was challenged, the Alliance made ‘best for project’ decisions to carry out additional investigations or design work to pursue alternatives. As an example, the powerful tool of Computational Fluid Dynamics was used in the analysis and design of flow deflector plates on the existing spillway, which were an alternative to the originally designed gate locking pins. The investigation and development of this alternative resulted in significant cost savings and a more effective design solution.
This paper presents aspects of the design carried out by the Wivenhoe Alliance, lessons learned, and the way continual investigations during construction provided value for money solutions.