Symposium

Management for Safe Dams

Dams are a benefit to the society. The symposium purpose is to share information to maintain or increase the safety of dams and their associated benefits. There is a growing interest from both authorities and investors that contribute to the development and complements ICOLD initiatives. Global Standard On Tailings Management and updating of national legislation and guidelines are examples.

We encourage contributions on the six themes for dams with various purposes such as hydropower, flood control, irrigation, levees and other consumptive uses, as well as mine tailings.

Symposium Themes

The topic of dam safety management can cover a broad field of aspects and according to the ICOLD bulletin 154 the system should:
“establish a systematic and consistent way of transforming an operating organization’s values, principles, policies and procedures into the products or outputs of industrial or commercial activities”

Sub-activities that could be part of the systematic work commonly starts with a set of policies and objectives followed by planning of activities and resource allocation to achieve the objectives when implemented. A crucial, but complicated, objective is to define what a tolerable risk level is. Sometimes the end result could be to apply the principle to reduce risks as low as reasonably practicable (ALARP).

To be able to evaluate if the dam safety management system maintain operation in line with its defined objectives, monitoring and evaluation is needed. Utilization of the information collected in monitoring and evaluation should be used for audits and review, preferably by independent reviewers. Finally the outcome of monitoring, evaluation, audits and reviews should be used for tuning and updating the dam safety management system in continuous improvements.

Not only the owners, board of directors, CEOs and other executives, competent and commited as well as dam safety employees are part of the dam safety management. Also the investors could have an important role to influence or form requirements on the governance and safety management to initiate cooperation.

A reliable and efficient dam safety management system is dependent on input from high quality data on the current status of dams to be able to make knowledge based decisions. Used methods, systems, technologies and organizational set-up is therefore of major importance to verify the dam safety level and to evaluate current status of the dams and their reservoirs.

Surveillance is commonly based on a range of sources from routine rounding and visual inspection to advanced high-tech instrumentation and data analytic tools and e.g. artificial intelligence for evaluation of collected data. A challenging part of data evaluation is the definition of relevant alarm and alert levels where different types of action must be taken to prevent a potentially dangerous situation for a dam.

On existing dams the condition monitoring and assessment of the current and potential future status, or remaining service-life of a structure could be in focus. A cost-effective approach on assessment is to apply the principle of progressive screening which imply that the status or condition of a dam is defined by successively increasing the level ofdetails when needed. Commonly the degree of details in the assessment often correlate to the level of insight of the actual status or knowledge on e.g. origin for any degrading processes ongoing.

Regardless of what type of analysis is carried out, a model is needed, i.e. an image that describes how to interpret the effect on the studied part of the facility, thus forming the basis for the simplifications and assumptions being made. Analysis can be anything from simple behavior models via analytical calculations to advanced numerical simulations. The purpose of the analysis is commonly to utilize collected data to investigate if e.g. dams and spillways fulfill the requirements. The results can also be used to suggest further investigations and monitoring due to lack of data, or suggesting and evaluating the effect of different mitigating measures. Aspects on different methodologies and validation of models or definition of acceptance criteria’s are of major interest to get reliable results as basis for decisions. Models for decision between different courses of action can be based on a vast amount of parameters like safety aspects, technical, environmental, aesthetical, practical and last but not least, cost.

Measures are taken when the deviation fromset requirements is not acceptable (now orin the future). It is often a matter of reducing the load, slowing down the development of degrading or increase/restore the performance or capacity. Surveillance with planned inspections, and/or monitoring, can be used for evaluating potential development is sometimes selected instead of a physical measure. Methods for design and construction of measures for rehabilitation of dams, reservoirs, hydraulic design, mechanical equipment, waterways and other appurtenant structures are of great interest. Lessons learned from projects and incidents can be presented in case studies. Experience from follow-ups of previously performed rehabilitation and dam safety measures are crucial to feed the process of continuous improvements and are valuable to share with the dam community.

A warmer climate with increasing climate variability will increase the risk of both droughts and floods.

The changing climate and increased expectations from the society on dam owners implies actions. One of the challenges for the sustainable energy system is to ensure balance in the power system. Here, hydropower, with its flexibility and costeffective regulating capability, play a key role. A further challenge is to handle the demand for ecological rehabilitation and biodiversity of dammed and regulated rivers. Both the aspects on balance of the power system as well as biodiversity must be dealt with the prerequisite to fulfill the dam safety requirements and also handle the potential contradiction between the aspects.

Topics like environmental effects of hydropeaking, effects on the dams and the reservoirs by changing dam operations, prioritization between electricity production and environmental flows, effects of increased hydropower production will be discussed. Methodologies to mitigate any negative effects and reports from case studies and applicable technologies to reach these aims are of major interest.

The world is facing an unprecedented change towards electrification driven by the Paris agreement heading towards a fossil-free society. This electrification cannot take place without an updated and sustainable hydropower designed to regulate an increasing amount of intermittent energy sources as well as mining activities for raw materials. Interdisciplinary research and innovative solutions, developed in close cooperation between academia, industry and the public sector will strengthen the position of the dam community. Hence researchers from different disciplines, industry and the public sector need to find innovative, mitigating, solutions on a multitude of issues that could have a negative impact on hydropower units, dams and rivers.

The theme will focus on innovative solutions regarding new technologies and methods that can be related to all the previous themes T1-T5 but with focus on the innovative part.

Photo below © Landafors-Ljusnan

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