A brief overview of dam surveillance is given from a South African perspective and more specifically the perspective of the Department of Water Affairs and Forestry (DWAF). DWAF’s Ten Commandments for the design of dam monitoring systems serve as introduction and this is followed by a summary of the design steps. The various parameters that can be measured and the South African preferences are discussed briefly followed by a synoptic description of crack and joint monitoring in South Africa. This provides the background for DWAF’s recent developments in 3-D Crack-Tilt gauges. Some of DWAF’s achievements as well as some of the blunders made by the author during the past 30 years are illustrated by means of a few case histories.
This paper reviews the general principles of duty of care which assist in the understanding of responsibilities that may exist for surveillance of dam safety, including the inter-play of the common law and statutory law. Only when there is a foundation in the general principles can obligations upon dam owners/operators with respect to surveillance and instrumentation be interpreted. Some legal issues around the development and use of industry guidelines are also explored.
D.N.D. Hartford and P. A. Zielinski
With the notable exceptions of dyke safety in the Netherlands and dam safety in Australia, explicit consideration of the equity versus efficiency dilemma associated with dam safety decision-making has been virtually ignored in the past debates related to safety of dams thus leading to inconsistent judgments in the development of dam safety policies. The equity-efficiency dilemma is now being debated in Canada as part of the process of revising the Canadian Dam Safety Guidelines. This paper explains how the argument in favour of formulating the new Canadian Dam Safety Guidelines within the formal risk assessment and risk management framework is being presented. The paper then focuses on the difficulties involved in aligning the well tried and tested and generally successful traditional approach to dam safety with the relatively untried and untested risk assessment approach. While the paper does not provide a significantly different perspective (a made in Canada approach) to the role of risk assessment in dam safety management as established in Australia and as presented in ICOLD Bulletin 130 (ICOLD, 2005), it does challenge some aspects of the ways dams are classified in the emerging risk assessment frameworks for dam safety management.
The Requirement for Dam Instrumentation from a Queensland Regulatory Perspective ANCOLD 2006 Conference – Instrumentation and Survey Seminar Page 1 THE REQUIREMENT FOR DAM INSTRUMENTATION FROM A QUEENSLAND REGULATORY PERSPECTIVE Peter Allen, Director Dam Safety (Water Supply) Department of Natural Resources and Water ABSTRACT This paper presents the Queensland dam safety regulator’s views on issues to be considered when designing and implementing instrumentation for referable dams in Queensland. It also summarises the general requirements for dam instrumentation contained in the Queensland Dam Safety Management Guidelines and gives some thoughts on what should be contained in any ANCOLD Instrumentation Guideline.
Janice H. Green and Jeanette Meighen
The Probable Maximum Precipitation (PMP) is defined as ‘the theoretical greatest depth of
precipitation that is physically possible over a particular catchment’. The PMP depths provided by
the Bureau of Meteorology are described as ‘operational estimates of the PMP’ as they represent the best estimate of the PMP depth that can be made, based on the relatively small number of large events that have been observed and our limited knowledge of the causative mechanisms of extreme rainfalls.
Nevertheless, the magnitudes of the PMP depths provided by the Bureau are often met with scepticism concerning their accuracy when compared to large rainfall events which have been observed within catchments and which are, typically, only 20% to 25% of the PMP estimates. The recent increases in the PMP depths, resulting from the revision of the Generalised Tropical Storm Method (GTSMR), have served only to entrench this cynicism.
However, analyses of the magnitudes of the storms in the databases adopted for deriving PMP depths show that these observed storms constituted up to 76% of the corresponding GTSMR PMP depths and up to 80% of the Generalised Southeast Australia Method PMPs for the storm location. Further, comparisons of the PMP depths to large storms observed in similar climatic regions around the world indicate that the PMPs are not outliers.
The results of these analyses are presented for a range of catchment locations and sizes and storm durations and demonstrate that the PMP estimates provided by the Bureau of Meteorology are reasonable and are not unduly large.
SunWater manages its portfolio of 29 major dams through 6 business centres each responsible for the Dam Safety Program for the dams under its management control.
The effectiveness of responses during an emergency depends on the amount of planning and training performed. Management must show its support for dam safety programs and the importance of emergency planning.
If management is not interested in community protection and in minimising property loss, little can be done to promote dam safety. It is therefore management’s responsibility to see that a program is instituted and that it is frequently reviewed and updated.
The input and support of all communities must be obtained to ensure an effective program. The emergency response plan should be developed locally and should be comprehensive enough to deal with all types of emergencies specific to that site.
SunWater is a responsible dam owner and has recently upgraded all its emergency action plans in consultation with emergency services of Queensland. This paper details the basic steps to handle emergencies of water infrastructure. These emergencies include inflow floods, rapid drawdown, earthquake, sunny day failure, changes in reservoir water quality and terrorist attacks including hoax.
This paper is intended to assist small dam owners that do not have dam safety programs in place. It is not intended as an all inclusive safety program but rather a provision of guidelines for planning for emergencies.