P. J. N. Pells and M. Hunter
The potential for generating acid leachate from waste dumps is a major consideration in many metalliferous and coal mines. This paper describes the construction of the highest embankment dam in Indonesia for the sole purpose of storing potentially acid producing waste under water. The paper discusses the features of embankment dam design peculiar to an open pit mining environment which involves moving more than three times the total volume of earth and rock than in the whole of the Snowy Mountains Scheme.
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Now showing 1-12 of 33 2963:
David S. Bowles, Loren R. Anderson, Joseph B. Evelyn, Terry F. Glover and David M. Van Dorpe
A demonstration risk assessment was conducted on the 283-foot high rolled-earthfill Alamo Dam as part of a U.S. Army Corps of Engineers (USACE) Research and Development program. The existing dam and 19 structural risk reduction alternatives were evaluated for flood, earthquake and normal operating conditions. The paper summarizes the risk assessment process, results, findings and recommendations. It also provides an evaluation of the risk assessment process and recommendations for better positioning the USACE to use risk assessment for dam safety evaluation and decision support.
Kumara Arachchi and Kelvin J Lambkin
Wetlands by their very nature act as storages of pollutants and nutrients in systems subject to environmental stresses. Wingecarribee Swamp acted in this manner and enhanced the quality of catchment runoff flowing into the Wingecarribee Reservoir until the structural failure of early August 1998 in which 6000 megalitres of peat and sedimentary material were moved into the Reservoir. Protection of the Swamp’s functions and values is directly related to Sydney Catchment Authority’s core objectives of protecting the environment and protecting public health by supplying drinking water of acceptable quality. Due to the catastrophic failure, water quality in the reservoir and the ecological integrity of the Swamp have been compromised. The incident has also resulted in significant dam safety issues.
This paper describes the dam safety, catchment management and water quality response to the failure of a major peatland which covered 8% of the catchment of Wingecarribee Reservoir in the Southern Highlands of New South Wales.
ANCOLD Environmental Guidelines have been under preparation for a considerable time. A brief for their preparation followed a resolution by the ANCOLD executive in 1991] that:
“ANCOLD should be seen by the profession and the community as a credible and informed source of information on the risks and benefits associated with dam projects.”
Why the guidelines were initiated, why they have taken the time they have to prepare and what they cover are described in this paper.
To the author’s knowledge, they are the only guidelines of their type, addressing the environmental effects of dams and associated works. It is hoped that they generate substantive debate. This paper initiates the public comments phase.
The paper has two purposes:
° = To introduce the guidelines ° To use the guidelines to introduce this environmental issues session of this conference
Jim Walker, Murray Gillon and John Grimston
Karapiro Dam is at the end of a cascade of hydropower dams on the Waikato River in New Zealand’s North Island. The 52m high, high hazard, arch dam retains the lake for a 96MW power station at its downstream toe. Safety reviews recommended a re-evaluation of the dam stability under seismic loading.
Dam owner, Electricity Corporation of New Zealand (ECNZ), commissioned consultants Tonkin & Taylor Ltd to carry out a series of studies and investigations which provided better understanding of the dam’s safety status. Investigations located a previously unrecorded continuous low strength thrust fault underlying the left abutment. This provided the potential for movement of the left abutment gravity blocks under earthquake loading, with adverse effects on arch dam and reservoir safety. Investigations showed the abutment cut off walls to be lower than the PMF lake level. High groundwater levels and erodible pumiceous soils were found at the left abutment. These findings prompted ECNZ to implement stability enhancement works.
This paper describes the studies and investigations, peer review process, and design and construction of enhancement works.
Allan J Crichton , Ikhlef Benzenati, Tony J Qiu and Jon T Williams
The Sg Kinta Dam is a 90 m high Roller Compacted Concrete (RCC) gravity dam and is expected to be the first RCC dam in Malaysia when construction commences in 2000. The dam is part of the development of the Ipoh Water supply on mainland Malaysia. A thermal – structural analysis has been completed as part of detailed design using ANSYS finite element analysis software to assess the effect of the heat of hydration of the RCC on resulting structural stresses. The effect of using simple linear elastic material properties on the calculated stresses has been compared to more complex time variant material modulus and creep analyses. From these comparisons it is shown that the simple models overestimate initial stresses and underestimate or cannot predict the long term tensile stresses.