The 2011 Tohoku Earthquake of magnitude 9.0 shook the east Japan and caused enormous damage. As of September 22, The Japanese National Police Agency has confirmed 15,805 deaths, and 4,040 people missing, as well as over 295,047 buildings completely or partially destroyed. About 8,700,000 homes lost power, and about 2,290,000 homes were shut down from water supply. The transportation lifelines such as highways and railways including Shinkansen (high speed train) were disrupted. The earthquake triggered extremely destructive tsunami waves of the height of 15 metres, in the east coast of the Pacific Ocean. Fukushima No.1 nuclear power plant had accidents.
2011 – Perspectives of the 2011 Tohoku Earthquake and Tsunami
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Awoonga Dam is the sole source of water for the City of Gladstone and the heavy industries in the region. The area’s distribution reservoirs hold little more than a day’s supply. Extended water supply disruption could have severe economic impacts.
The nine large valves in the inlet tower and river outlet of the dam cannot be inspected or maintained without shutting down the entire water abstraction system. Consequentially limited maintenance has been carried out in the 25 years since the valves were installed.
Recent Dam Safety inspections carried out for the dam owner, the Gladstone Area Water Board (GAWB,) noted some deterioration of the valves and recommended that the valves should be removed, inspected and refurbished as necessary
GAWB was thus presented with a daunting challenge to refurbish valves at Awoonga Dam, as it was generally believed that their removal for refurbishment would not be possible within the time limitations imposed by the system and customer requirements.
In 2008 GAWB commissioned GHD to develop a strategy to refurbish the valves within a 12 hour shutdown period. The strategy proposed and adopted required a rigorous risk management approach and close collaboration between GAWB’s operational staff, two contractors and the consulting engineers. The work was successfully completed during 2011.
This paper discussed the strategies and processes developed and how the project planning, supervision and execution was driven by the risk management based approach. It also highlights some of the experiences and lessons learnt during the project.
2011 – Refurbishing Outlet Valves utilising Shutdown Periods
The large flood inundating areas of Brisbane and Ipswich along the lower Brisbane River below Wivenhoe Dam in January 2011 was extensively reported by the media. An independent Commission of Inquiry was formed soon after the flood with broad terms of reference including matters related to dam operations. Prior to the Inquiry hearings and findings, reporting in the media continued and made strong allegations of blame of the flood on dam operations. The media relied on limited expertise but the articles were portrayed and subsequently re-produced by other media outlets as ‘expert’ analyses. The author’s interpretation is that media claims were misleading and damaging to the public confidence in the role of dams for flood mitigation, and this damage occurred before official Inquiry findings were available.
A brief summary is presented of now publicly available credible reports on the flood event, and a summary is also presented of the key matters and allegations reported in the media related to the dam operations. An analysis and commentary of media reporting on the flood operations of the Wivenhoe Dam is presented in the context of time and people with reference to information and expertise available to the media, and media conduct in relation to fair public interest and professional practice.
Matters of importance for objective and informed knowledge of key technical matters in relation to operation of dams, dam safety, and the inevitable extremes of nature and floods are discussed. The paper then examines the roles and possible limitations of dams engineering professionals in relation to media reporting of such matters.
This paper solely focuses on matters of media examination of the floods and dam operations, and generally does not comment on technical matters that are in the terms of reference of the Commission of Inquiry.
2011 – January 2011 Brisbane River Floods and Examination by Media of the Dam Operations
This paper provides the insight of one practitioner into the process and application of Dam Safety Risk Assessment. The ANCOLD Guidelines on Risk Assessment provide a reasonably comprehensive outline of the key tasks involved in the risk assessment process. The intent of this paper is not to rehash the Guidelines but rather to discuss some of the practicalities of completing a dam safety risk assessment and highlight some key learning’s gained from a wide range of projects for a number of different owners.
The paper includes a brief overview of each component of the risk assessment process as well as some of the advantages and disadvantages of the various approaches to completing a risk assessment project.
2011 – Dam Safety Risk Assessment – A Practitioner’s Perspective
Dan Forster, Murray Gillon
A robust and defensible dam surveillance process is considered to be the ‘front-line of defence’ in ensuring dams do not present an unacceptable risk to people, property and the environment. The concept of a ‘Quality Chain of Dam Surveillance’ describes the surveillance process as a multi-linked chain where each step in the process forms a critical link. Without rigorous attention given to quality assurance links in the chain can become tenuous or broken and thus compromise the integrity of the whole chain. Hydro Tasmania is currently re-engineering its existing surveillance process using the Quality Chain of Dam Surveillance as a basis.
This paper presents the concept of the quality chain and uses the Hydro Tasmania improvement initiative as an example application of the concept. The paper is intended to provide a fresh perspective on what is sometimes considered a stale topic and reinforces the need for a considered approach to dam surveillance.
2011 – The Quality Chain of Dam Surveillance
Lesa Delaere, Ivor Stuart, Thomas Ewing, David Marsh
As part of Wide Bay Water’s commitment to minimising environmental impacts of its water supply weirs, a “Nature Like” Fishway is under development for the Burrum No 1 Weir. This project is a fishway offset provision for the raising of Lenthalls Dam in the upper reaches of the Burrum River in Hervey Bay. The Burrum No 1 weir forms the primary pumping pool for the Hervey Bay water supply and is located at the tidal limit of the Burrum River. Understanding fish biology and behaviour is critical to the effectiveness of the design of a fishway as much as the balance between the goals of maximising fish passage versus cost, construction and operational difficulties that a fish passage solution may present.
This paper presents the aquatic ecology of the project and the inter-relationship of fish biology and river flow frequency. It discusses the fish species of the Burrum River, their behaviour, seasonal migration and criteria for successful passage. It presents the analysis of river flows with respect to frequency and headwater/tailwater relationships to weir drownout, which was complicated by the tidal flow regimes downstream of the weir. These aspects were also applied in consideration of river behaviour; low flow characteristics for fishway operation during dry seasons and drought, and high flow characteristics during the wet season and floods.
The biological needs for successful fish passage for two very different river flow characteristics were analysed. This allowed targeted design criteria and fishway solution to be developed to provide maximum benefit without causing undue cost to the project.
Burrum Weir Fishway – Fish Biology and River Flows: Two Faces