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.
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Dr Judy Henderson
Against a background of several decades of increasingly polarised and acrimonious debate, the World Commission on Dams (WCD) was established in 1998 with a two year mandate to review the development effectiveness of dams, assess alternatives for water resources and energy development and develop internationally acceptable criteria and guidelines for future decision- making. This report discusses the role of large dams in development and the challenges of water resource management in the future. T the work program of the WCD is outlined and progress to date on fulfilling its mandate.
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.
Among the major energy options, Large Hydro Power is considered to be the front ranking and renewable. But, in most of the developing countries including India, the large multipurpose dam
projects are shrouded in controversies.
This paper, while dealing with positive and negative impacts of large multipurpose dam projects, Jocuses on Social Impact Assessment’ and its mitigatory measures, for the success of the project. The Environment cost as well the Human cost of such projects should be judiciously integrated in the project cycle from its conception to its post implementation stage, for sustainable development of this
Buddhima Indraratna, Mark Locke and Gamini Adikari
The main objectives of the filter are to prevent erosion of the dam core, permit controlled passage of seepage flow through the dam and facilitate dissipation of excess pore pressures in the core. In most designs of dam filters, empirical methods based on particle size ratios have been used. These empirical rules are developed through extensive laboratory tests. Although the empirical rules benefit from directly or indirectly incorporating most factors affecting filtration, they cannot be extrapolated for distinctly different soils and do not describe the time dependent changes that occur within the filter medium.
Mathematical models can be formulated to explain the fundamental physics of particle interaction and migration, within a framework of well defined geohydraulic constraints. Considering the mass flow and momentum conservation principles; time dependent changes in particle size distributions, mass flow rates, retention capacity and base soil erosion rates can be simulated.
This paper reviews various empirical and mathematical models, based on the authors experience. A novel approach to large scale filtration is highlighted based on testing actual soil and filter materials from an Australian dam, in a new 500mm diameter apparatus.
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.