Dam Surveillance Guide

Dams are part of human achievements that induce great benefits for society but also bear a potential risk to people, property and the natural environment. The risk of a dam rupture is extremely low and diffi cult to quantify accurately. The aim of ‘Dam surveillance’ (ICOLD Bulletin 158), is to help reduce these risks by early detection of an undesirable event. The objective of dam surveillance is to make a precise and timely diagnosis of the behavior of dams, in order to prevent undesirable consequences. Both the monitoring system and surveillance program has to be designed and should be able to detect any abnormal behaviour. ‘Dam surveillance’ (ICOLD Bulletin 158), emphasizes the following aspects: • Routine visual inspection • Special inspection • Checking and testing of Hydro-electromechanical equipment • Monitoring parameters and devices • Automation • Maintenance of ageing monitoring systems • Re-instrumentation of existing dams • Recent developments • Data management • Dam documentation management • Assessment of dam condition and behaviour • Assessment of routine dam safety monitoring programme • Prioritization of maintenance, remedial and upgrading works.

Dams are part of human achievements that induce great benefits for society but also bear a potential risk to people, property and the natural environment. The risk of a dam rupture is extremely low and diffi cult to quantify accurately. The aim of ‘Dam surveillance’ (ICOLD Bulletin 158), is to help reduce these risks by early detection of an undesirable event. The objective of dam surveillance is to make a precise and timely diagnosis of the behavior of dams, in order to prevent undesirable consequences. Both the monitoring system and surveillance program has to be designed and should be able to detect any abnormal behaviour. ‘Dam surveillance’ (ICOLD Bulletin 158), emphasizes the following aspects: • Routine visual inspection • Special inspection • Checking and testing of Hydro-electromechanical equipment • Monitoring parameters and devices • Automation • Maintenance of ageing monitoring systems • Re-instrumentation of existing dams • Recent developments • Data management • Dam documentation management • Assessment of dam condition and behaviour • Assessment of routine dam safety monitoring programme • Prioritization of maintenance, remedial and upgrading works.

Prepared by the Task Committee on Instrumentation and Monitoring Dam Performance of the Hydropower Committee of the Energy Division of ASCE. This report is a handy and comprehensive source of information for dam owners, engineers, and regulators about instrumentation and measurements for monitoring performance of all types of dams. It presents the methodology and process for the selection, measurement instruments and techniques, installation, operation, maintenance, use, and evaluation of instrumentation and measurement systems for dams, appurtenant structures, their foundations, and environment. Topics include: factors affecting dam performance, means and methods of monitoring dam performance, planning and implementation of a monitoring program, data evaluation and reporting, and decision making. Case histories of instrumentation and monitoring programs at specific dams are provided for the reader. Product Review "I highly recommend this comprehensive reference on instrumentation used to evaluate dam performance. All owners, engineers, and regulators of dams should own a copy of this book." ?Fred Sage, Field Branch Chief, California Division of Safety of Dams

Dam decommissioning or dam removal has been increasingly common since the past decade. The reason for considering dam removal may have to do with the safety of dams, high repair costs, high operating and maintenance costs, or effects on fish passage and water quality. However, the decision to remove a dam must be based on careful evaluation of the alternatives to address the specific problem at each dam. The ICOLD Committee for decommissioning dams was established in 2005 to develop information that can be used by ICOLD members to respond to questions about the dismantling of dams and to provide a forum for the exchange of information . This ICOLD Bulletin is not intended as a design guide, but as a guide to the decision making process, consultation and regulatory approvals, design and construction issues, sediment management and performance monitoring. The primary aim of these Dam decommissioning guidelines is to provide dam owners, dam engineers and other professionals with the information needed to guide decision making when considering dam dismantling as a project alternative. They are not meant to be used as a design guide, but as a guide to highlighting the points of interest. The guidelines in this ICOLD Bulletin apply only to flood defense structures and not to fall dams.

ICOLD Bulletin 180 presents the vast experience gained over the past 6 decades by the dam engineering community in the field of dam surveillance by means of 80 case histories. The documented case histories endeavour to cover the practical experiences related with one or several of the following points: a) Methods for the improvement of the quality and reliability of information. b) Data processing and representation techniques. c) Effective Diagnostic analyses to determine behaviour patterns. d) Dedicated surveillance systems for the optimization of maintenance, rehabilitation, and other life cycle costs. e) Impact of surveillance on preventing dam incidents and dam failure. f) Overview of dam surveillance management systems. The case histories cover a wide variety of technical aspects and deal with success stories but also incidents, some of them with catastrophic consequences. The time framework spans over 70 years: from the times of the Second World War up to the present. The purpose is to learn from these practical experiences, not to criticize the involved individuals, who had to work with the techniques and rules of practice available at the time. This bulletin wants to contribute to keep learning from the experience of the dam engineering community, specifically in the field of dam surveillance. Some of the case histories are widely known and have been described and analysed in numerous publications. Most of them are related to famous dam failure incidents and were compiled as international “benchmark case histories” for this bulletin to focus on the specific lessons learnt related with dam surveillance. Le Bulletin de la CIGB 180 présente la vaste expérience acquise au cours des 6 dernières décennies par la communauté des ingénieurs de barrages dans le domaine de la surveillance des barrages au moyen de 80 histoires de cas. Les histoires de cas documentées s'efforcent de couvrir les expériences pratiques liées à un ou plusieurs des points suivants : a) Méthodes d'amélioration de la qualité et de la fiabilité de l'information. b) Techniques de traitement et de représentation des données. c) Analyses diagnostiques efficaces pour déterminer les modèles de comportement. d) Systèmes de surveillance dédiés pour l'optimisation de la maintenance, de la réhabilitation et des autres coûts du cycle de vie. e) Impact de la surveillance sur la prévention des incidents et des ruptures de barrage. f) Aperçu des systèmes de gestion de la surveillance des barrages. Les histoires de cas couvrent une grande variété d'aspects techniques et traitent de réussites mais aussi d'incidents, dont certains avec des conséquences catastrophiques. Le cadre temporel s'étend sur 70 ans : de l'époque de la Seconde Guerre mondiale à nos jours. Le but est d'apprendre de ces expériences pratiques, pas de critiquer les individus impliqués, qui ont dû travailler avec les techniques et les règles de pratique disponibles à l'époque. Ce bulletin veut contribuer à continuer d'apprendre de l'expérience de la communauté de l'ingénierie des barrages, en particulier dans le domaine de la surveillance des barrages. Certaines des histoires de cas sont largement connues et ont été décrites et analysées dans de nombreuses publications. La plupart d'entre eux sont liés à des incidents de rupture de barrages célèbres et ont été compilés en tant qu'« histoires de cas de référence » internationales pour ce bulletin afin de se concentrer sur les leçons spécifiques apprises liées à la surveillance des barrages.