Regulatory risk for large civil engineering projects such as dams and hydropower schemes can be larger than the engineering risks. The seriousness of project regulatory risks is rarely acknowledged publicly and almost never dealt with contractually. The recent adoption by the World Bank of the FIDIC/ITA Emerald Book contractual framework introduces geotechnical baseline reports as a contractual mechanism for managing ground risk in World Bank hydro projects. Regulatory risks created by government agencies and utilities due to changing project requirements can likewise be managed by adopting the concept of geotechnical baselines to regulatory impositions as a baseline report.
Government agencies changing regulatory burdens mid project can fairly be held accountable for the
burdens of those changes by establishing regulatory baselines at the earliest stages of a project. By
contractually embedding regulatory risk baselines, governments and their agencies can adjust their
payments to reflect the changed cost in delivering an agreed project caused by regulatory changes. In this way the compensation for delivering a project more closely aligns with its value and cost. A regulatory baseline report in reducing project exposure due to regulatory change driven costs is a new tool in more efficient and competitive project delivery.
A transparent mechanism for costing regulatory change risk and apportioning it in accordance with pre agreed mechanisms, is an innovation of great use to the dam and hydropower sector.
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Alberto Scuero, Gabriella Vaschetti, John Cowland
Efficiency in water supply reservoirs, even more so in pumped storage reservoirs, requires good water management and minimisation of water losses. With climate change affecting the quantity of water available for supply and power generation, minimising water losses is becoming more and more crucial, and the most efficient way to achieve this critical objective is to line the reservoir with a watertight geomembrane system. With more than 60 years of use, flexible geomembrane systems have proven to be a dependable technology for new construction as well as for rehabilitation. Efficiency can also be increased by covering the reservoir with a floating geomembrane cover to minimise evaporation losses, and by adding value to the reservoir with the installation of floating photovoltaic panel farms on the surface of the reservoir, to provide or increase electrical power generation. This paper addresses these two aspects of efficiency: water loss minimisation, by presenting concepts and advantages of geomembrane liners, and concepts and application
of floating photovoltaic farms with a case history in a water supply reservoir. The concept of a floating
photovoltaic farm on a pumped storage reservoir, and information on available guidelines for geomembrane systems and floating photovoltaic panels, are also presented.
Rachel Jensen, Adam Broit, Chriselyn Kavanagh
Downstream emergency response is a critical driver in the consequences and potential life loss associated with dam flooding and failure. This response is highly varied between stakeholders, communities and the nature of the flooding or dam threat. As assessments on dam failure consequence and potential loss of life become increasingly important in understanding holistic dam risk, they are also becoming increasingly complex.
As part of a portfolio wide Comprehensive Risk Assessments, Sunwater have undertaken workshops with a wide range of stakeholders to better understand downstream emergency response and the warning timeline. The workshops have been aimed at facilitating better downstream stakeholder engagement, obtaining key data for consequence assessments and developing consistency in assumptions for potential life loss.
This paper presents the standardised methodology undertaken for warning time workshops, the outcomes for a range of downstream stakeholders and correlations between stakeholder groups which influence warning time response. These outcomes may be used by practitioners in the absence of catchment specific warning time data and provide a counterpoint to international standard warning time assumptions.
David Reid, Andy Fourie, Riccardo Fanni, Cristina Vulpe, Alexandra Halliday
Recent failures of a number of tailings storage facilities (TSFs) has highlighted the need for better
governance and operational management of these structures. One means to improve their safety is clearly better and more focussed monitoring. Significant efforts are underway in this area, with a number of technologies being deployed. In particular, the monitoring of deformations through a variety of means (direct, satellite inferred) is increasingly being applied. While deformation monitoring to warn against failure has a long history in geotechnical engineering, some aspects of the rapid triggering and resulting flow of some TSFs may not be amenable to deformation monitoring, in the sense that actionable warning of an impending failure is not assured.
To examine this issue, a series of numerical models of an idealised TSF are carried out. This idealised TSF is brought to failure by means of a rising phreatic surface – often referred to as the constant shear drained (CSD) stress path. Deformations of the outer slope and crest of the numerical model – i.e. those that could be monitored for a real TSF – are tracked and analyses for the models carried out. It is seen that under CSD loading distinct deformation patterns indicative of impending failure are not always clear. Rather, minimal deformations and indeed swelling of the crest is seen leading to failure. The importance of recognising the minimal pre-failure deformation patterns that may manifest with a rising phreatic surface is noted.
Hench Wang, Edward Funnell, Albert Shen, Matt Scorah, Peter Hill
The use of simulation models to assess dam failure consequences has progressively advanced in Australia over the past few years. For example, it is now common for HEC-LifeSim to be used to estimate potential loss of life from the failure of large dams with large populations at risk downstream. Since its introduction to Australia, numerous presentations and papers have been provided by USACE and industry professionals that highlight the benefits of using HEC-LifeSim Version 1.0.1 for a range of different case studies.
This paper identifies some of the new features in the latest version of HEC-LifeSim that can improve the robustness and defensibility of the potential loss of life estimates for dambreak consequence assessments. The techniques that have been used to overcome these challenges are also discussed using some case studies.
The first case study demonstrates the sensitivity of the model performance and potential loss of life to changes in version and number of iterations used to simulate the life loss. This is done by comparing the differences in simulation run time and life loss between the previous and new versions of HEC-LifeSim for an example model. The second case study presents an example application of both versions of HEC-LifeSim to compare the results between one version and the other for a different dam and the final case study illustrates an improved method for interrogating the available outputs from HEC-LifeSim to provide the user with more information that otherwise could not be obtained from the default outputs.
Management of dams requires the use of experienced dam engineers and other competent personnel familiar with all relevant basic principles, technical guidelines, articles and manuals. This requires appropriate qualifications, registrations and adequate knowledge and experience relevant to the type of dam and the task required.
Engineering services in Queensland must comply with the Professional Engineers Act 2002 which requires a registered professional engineer of Queensland (RPEQ) to undertake or directly supervise an engineering service. Attributes in addition to RPEQ are recommended for personnel responsible for dam safety management. Inputs are often required from non -engineering technical specialists, such as geologists. Supervising these inputs in the context of meeting the Professional Engineers Act 2002 should be considered.
A matrix of skills for dam safety management personnel has been prepared as part of the Queensland dam safety management guideline and subject to extensive stakeholder feedback in its preparation. The matrix consists of a list of roles typically required for dam safety management and, for each role, a corresponding set of recommended core attributes.