Roy Fenderson & Wayne Peck
Although most people realise that earthquakes cannot be predicted, the Community expects that Dam Owners will utilise leading edge technology and the latest scientific understanding of earthquakes to mitigate the impacts of significant earthquakes once they occur.
The rapid analysis of large earthquake events with respect to critical dams can greatly enhance an emergency response. In order to achieve this enhancement, three sequential, interdependent processes must be in place. These processes are data collection, processing of the data into intelligent warnings and responding to the warnings appropriately. The absence of any one of these three processes or three “legs of the stool” destabilises the other two – greatly reducing the effectiveness of the whole.
This paper will discuss how Hydro Tasmania and the Seismology Research Centre designed, operate and manage an innovative system that encompasses the first two processes, and how their results integrate into Hydro Tasmania’s Dam Safety Emergency Plan (DSEP).
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To obtain a resource consent to build and operate any new water resource or hydro-electric development in New Zealand, the developer is required by the Resource Management Act (RMA) to consult with the community over the effects that the development could have, including describing how public safety risks will be avoided, remedied or mitigated. The community has the opportunity to respond to the authorities issuing the resource consent and influence the conditions attached to the consent.
The proposed Project Aqua Scheme in the South Island, New Zealand, comprised a 60 km long canal system to convey 340 cumecs flow from the Waitaki River across alluvial river terraces and through a chain of six hydro-power stations before returning the water back to the river. Each section of canal between stations would have contained between 4 and 6 million m3 of water within embankments up to 20m high. A breach of any one of these canals had the potential to flood farmland, residential buildings, highways, and other infrastructure, thereby posing a safety risk to local residents together with the potential for significant economic loss.
The paper describes the methodologies that were developed and used to assess the impacts, the measures proposed to avoid, remedy or mitigate safety risks and the public reaction to the associated report that was provided for public consultation prior to abandonment of the project. The methodologies used required adaptation of dam safety and consequence assessment practices usually applied to in-river dams, and applied here to the 60 km long length of canal embankment.
A Bodley, J Phillips and P Cesare
The PT Kelian Equatorial Mining (KEM) Gold Mine is located in the foothills of Central Kalimantan in Indonesia, only 3km south of the equator. Namuk Dam was completed in September 1991, to receive tailings from the gold mine that commenced commercial production in January 1992. Mining operations ceased in mid-2003.
Progressive closure of the mine has been underway since 2003, but processing of ore stockpiles will continue to the end of 2004.KEM and the local Government formed a Mine Closure Steering Committee, supported by four Working Groups to provide assistance and guidance to KEM in achieving responsible closure of the mine.
Engineering aspects of the Namuk Dam closure included flattening of the downstream slope to withstand overtopping in the event that the spillways should fail or be blocked for whatever reason. The design also required large rock to be placed as an apron over the tailings upstream of the dam as a security precaution against potential sabotage. This is intended to deter illegal mining of tailings, which could potentially initiate breach of the dam, and to protect the dam from malicious damage.
Project Aqua was planned to be a major hydropower development along the lower Waitaki Valley, New Zealand. Geotechnical investigations for the project were conducted in two main stages – from the late 1970’s to mid-1980’s, and again in the period from 2002 to 2004.
Community consultation was an important part of the 2002-2004 investigations, and was a key risk management issue for Meridian Energy. The proposed scope of the work included 512 drillholes and 734 test pits spread along the 60km project corridor. All proposed drillholes and test pits were subject to the Resource Management Act 1991 and needed Resource Consent applications, which required consultation with landowners, territorial authorities, and community and cultural groups including three Maori tribes.
A number of proposed investigations could not be undertaken because the landowner would not allow land access, but over 70% of the proposed work was completed with community support.
David Murray, Christopher Dann and Brent Mefford
Historically dams have been built across our river systems with little regard for the impacts on fish passage both upstream and downstream of the structure. Today’s increased environmental awareness and standards means that the impacts of a dam on the fish community are key issues that must be addressed by the operators of existing dams and in the design of new infrastructure.
Although fish transfer systems are currently being retrofitted to existing structures, there is a limited Australian knowledge bank on the performance of these systems and their impact on the fish communities. This lack of knowledge coupled with the potential for more strict environmental requirements in the future requires fish transfer systems to be designed with maximum flexibility and to rely on overseas practices where a greater knowledge bank exists but which may or may not be relevant to Australian conditions. For example, high lift fish transfer systems such as fish lifts and sluicing have been commonly used in North America for the last 20 years but are only now being considered for use in Australia.
This paper presents an overview of North American experience with the management of fish passage at dam structures and considers some of the following key issues relating to Australian conditions.
1. Upstream passage.
2. Downstream Passage
3. Sluicing as a method for conveying fish.
Suzie Gaynor, Phil Betts, David Watson
Community consultation is starting to become the ‘in thing’ to do for dam safety upgrades.
While ANCOLD has been promoting community consultation as an essential element in dam safety upgrades and is particularly highlighted in its most recent risk guidelines; there are many dam owners who have reservations about its value.
State Water is currently embarking on a series of upgrades and has included strategic ‘up-front’ community consultation in its approach.
This paper further builds on the paper given at the 2003 ANCOLD conference titled: “Keepit Dam Upgrade – The Community Consultation Way”, placing more emphasis on the value of involving the community, the added value that their involvement gives the project and how the community feels about being involved. This paper outlines the outcomes of two State Water projects embracing and practicing procedural justice.
The paper answers a range of questions including:
Involving the community is not just invaluable, it value adds.