Bayesian network-based approach for dam safety diagnosis

Dam failures pose catastrophic risks to human life and property, necessitating robust safety monitoring systems for risk mitigation. However, the specific contributions of distinct monitoring modalities to dam safety remain inadequately characterized, particularly regarding their differential impacts on structural integrity assessment. This study investigates the correlation between diverse monitoring modalities and dam structural safety through a comprehensive analysis of the Silin Hydropower Station dam. We analyzed 324 datasets collected from nine types of monitoring sensors installed across 36 dam cross-sections. Statistical analyses including one-way ANOVA, cluster analysis, and principal component analysis (PCA) were employed to quantify the influence patterns of monitoring parameters. The safety impact levels of all 36 cross-sections were systematically ranked, establishing a prioritized reference framework to inform decision-making in dam safety management. Unlike conventional dam safety assessments that predominantly rely on subjective empirical judgments, this study introduces an objective methodology integrating principal component analysis (PCA) of heterogeneous monitoring data across multiple dam cross-sections. The analytical outcomes were systematically quantified, hierarchically ranked, and visualized through multidimensional mapping techniques. The results demonstrated that variations in fissure (X2), horizontal displacement (X3), tilt (X4), stress (X6), soil-displacement (X8), and denotes water-level (X9) exerted highly significant effects on dam safety (p < 0.001). The first two principal components cumulatively accounted for 74.1876% of the total variance, with eigenvalues reaching 6.6769. In the comprehensive evaluation, cross-section T4 (T4) obtained the maximum score (0.8500), while cross-section T35 (T35) showed the minimum score (0.0175). In conclusion, the analysis revealed that X9, X8, X2, X3, and X4 exerted significant impacts on dam safety, while cross-section T4 achieved the highest comprehensive evaluation score. This approach employs Principal Component Analysis (PCA) with integrated scoring to reduce multivariate dimensionality, enabling rapid identification of key monitoring sections critical to dam safety, and demonstrates broad applicability for dam safety monitoring.

The use of risk assessment in dam safety management as advocated by the International Commission On Large Dams (ICOLD) will be greatly enhanced by Risk and Uncertainty in Dam Safety, an authoritative, comprehensive and valuable contribution to dam safety practices. Through the presentation of a systematic and integrated process, Risk and Uncertainty in Dam Safety assists the dam owner in evaluating the needs for dam safety improvement, selecting and prioritizing remedial and corrective actions, and improving the operation, maintenance and surveillance procedures. As a result of the unique cooperation among experienced and knowledgeable dam owners, dam safety mangers and engineers, and experts in the theoretical basis for risk assessment, Risk and Uncertainty in dam safety contains a thorough review of how state-of-the-art 'the industry' has become, provides lessons from first hand practical experience, and gives significant new contributions that will enhance understandingof the risk assessment and management process and how to apply it effectively, increasing awareness and reduce complacency regarding dam safety issues. Risk and Uncertainty in Dam Safety will appeal not only to industry specialists but also to readers outside the dam engineering community due to its general and excellent treatment of the various topics in the integrated process of risk assessment

PurposeFarm dam safety in Australia is being flouted and sustainability of catchments compromised because of the potential and severe consequences of dam failure. Hence, the purpose of this paper is to explore policy issues associated with safety of farm dam water storage through a comparison of developments in two Australian states against an analysis of international benchmarks and to provide an exemplar of best practice.Design/methodology/approachA strategic review and content analysis is firstly undertaken to establish international dam safety policy benchmarks ranging from minimum to best practice as well as selection guidelines for varying circumstances, and to identify an exemplar best practice model. Longitudinal study over a 12‐year period then provides the basis for case analysis in order to reinforce the established minimum level benchmark and to demonstrate the application of the benchmarked model policy selection guidelines.FindingsResearch results show that in Australia, South Australia is lagging international benchmarks for on‐farm dam safety management in a number of ways whilst a second state, Tasmania, provides leadership in this respect. The paper adds to the existing international benchmarking literature by identifying updated international best practice in private/farm dam safety assurance policy whilst establishing and providing longitudinal case study reinforcement for an acceptable minimum level benchmark in this area. The updated policy guidelines presented can be used to determine appropriate dam safety policy for any jurisdiction.Originality/valueThe paper provides an original contribution of analysis, establishment and case study validation of international benchmarks and guidelines on developing appropriate dam safety management and assurance policy for varying jurisdictional circumstances. In addition, it provides an updated exemplar of how policy benchmarks can go towards addressing cumulative threats of smaller dams in catchments not previously addressed.

As the country with the highest number of dams in the world, China’s dam safety management and risk control are crucial to public safety and economic development. This paper systematically analyzes the current status of dam safety in China, explores the causes of accidents such as design and construction defects, poor operation management, the impact of natural disasters, and proposes comprehensive dam safety management measures based on these analyses.

This paper sets out an Australian perspective on dam safety management. Dam safety is regulated by the six states that, along with the two territories, are self-governing, sharing powers with the federal government. The dam safety record of incidents and failures is similar to other developed countries, and two failures have resulted in loss of life. Where states do regulate dam safety, the current emphasis is on risk management, as it is for other hazardous industries, and risk assessment is permitted. Risk assessment has been used extensively to manage the safety of large dams in both regulated and unregulated jurisdictions and there is now more than 20 years of practice in portfolio dam safety management. Dam owners have found that risk assessment supports the need for due diligence for public safety and facilitates rational decision making between business investment priorities. The process of working towards risks that are as low as reasonably practicable satisfies both statutory and common law obligations.

Abstract. Dams as well as protective dikes and levees are critical infrastructures whose associated risk must be properly managed in a continuous and updated process. Usually, dam safety management has been carried out assuming stationary climatic and non-climatic conditions. However, the projected alterations due to climate change are likely to affect different factors driving dam risk. Although some reference institutions develop guidance for including climate change in their decision support strategies, related information is still vast and scattered and its application to specific analyses such as dam safety assessments remains a challenge. This article presents a comprehensive and multidisciplinary review of the impacts of climate change that could affect dam safety. The global effect can be assessed through the integration of the various projected effects acting on each aspect of the risk, from the input hydrology to the calculation of the consequences of the flood wave on population and assets at risk. This will provide useful information for dam owners and dam safety practitioners in their decision-making process.

Application of the Bayesian Belief Nets in dam safety monitoring The systems for earth dam monitoring should enable measurements of basic physical parameters describing the behavior of the structure, including: soil water pressure, soil stress, displacements, leaks, and drainage discharges. In the case of earth dam safety assessment, the monitoring data are used to detect any anomalies in dam behavior. In this paper, the dam safety has been analyzed using the Bayesian Nets. Two types of information: water pressure measurements and drainage discharge measurements are used in analyses. The seepage anomalies in the Klimkówka Dam were considered in demonstrate the practical advantages of using the Bayesian Nets for monitoring data interpretation. Presented examples of the Bayesian Nets applications (forward and backward propagation) in analysis of seepage through earth dams show that this method can be an effective tool supporting an assessment of dams technical condition and monitoring of the dam safety.

ABSTRACTThe Testalinden earth dam in southern British Columbia failed in June 2010 and created a huge debris flow. Homes were destroyed and property was damaged. The failure of this small dam resulted in a comprehensive review of over 1000 dams in the province, evaluation of dam safety management practices, changes to the Water Act and improvements in how data on dams are collected, archived and communicated. The provincial dam inventory was re-evaluated to ensure that appropriate consequence classification, and therefore attention, is assigned to dams. Increased scrutiny was placed on dam owners to ensure they complied with dam safety policies and to ensure they submitted annual inspection reports and formal dam safety reviews in a timely manner. Dam owners and professionals engaged in dam safety activities have received new guidelines and better education and training.

Recent attention to farm dams and dam safety in Australia and elsewhere reflects both safety and sustainability issues, and is driven by the fact that since built, many dam safety aspects have changed, e.g. population distributions, meteorological information, estimates of rainfall and runoff, engineering methods, and design standards and techniques. Farmers in Australia have often overlooked the common law obligation to review/design dams in line with current standards because of high engineering consulting costs: this leaves them vulnerable to litigation if their dam fails and the downstream community is susceptible to unacceptable risk levels. The seriousness of this problem has been demonstrated by case studies undertaken in the policy-absent State of South Australia and the policy-driven State of Victoria. In each state, ten hazardous private reservoirs were investigated for spillway adequacy in line with state-of-the-art practice. The investigation follows the release of an innovative Australian developed cost-effective spillway design/review procedure that has been made available and promoted in both states to minimize cost burdens to dam owners and encourage better dam safety management. Recent surveys undertaken in South Eastern Australia to test community attitudes to the procedure and implemented dam safety and water allocation policy in Victoria are also reported. These surveys together with the ‘spillway adequacy’ investigations clearly demonstrate that farmers require more than awareness and encouragement to ensure they look after their dams properly.

The hydropower station real-time safety monitoring is not only related to the safety, but also to the generation benefit of the power station. However, as the amount of monitoring data is very huge, and the dam structure is very complex, real-time monitoring cannot be carried out in most of the dam. It is useful to develop a high-performance safety monitoring system to assist the dam safety management work. As such, the paper introduces an expert system for dam safety management with a mode which can carry out the entire process of real-time dam safety monitoring, covering abnormal importing data, abnormal data changes, monitoring work, dam safety. The system has abundant functions such as dam safety analysis, visual query and remote consultation, etc. The system has been successfully applied to more than ten dam projects in China. The application shows that reliable data evaluation can identify data anomalies such as single point jump, multi point outlier and step change. Trend tracking can find possible structural changes. And clustering comprehensive evaluation can give a reasonable evaluation of the safety state of different parts of the dam. Complete online system can provide a supporting decision-making platform for the safety monitoring of the dams and improve the efficiency of power station management.

The Department of Irrigation and Drainage Malaysia (DID) has established a national guidelines on dam safety management for a safe governance of dams and resilient community surrounding the dams in Malaysia, titled Malaysia Dam Safety Management Guidelines (MyDAMS) in September 2017. This is the first national guidelines ever established. While the guidelines outline the best management practices on dam safety management, there is still a major gap towards its implementation into the dam industry. MyDAMS emphasized on all aspects of dam safety comprising legal requirements, potential hazards, safety principles, safety management system, investigation, design, construction, commissioning, operation and maintenance, surveillance and safety review, rehabilitation, emergency preparedness, changes and decommissioning of dams. There is a need to establish the framework of the government agencies towards its dam safety management as per MyDAMS. Meanwhile, the stakeholders have to gear up immediately towards capacity building to achieve the overarching objective of dam safety management as stated in MyDAMS. This paper discussed some required framework and way forward to be carried out by stakeholders on what entail next after the recent establishment of MyDAMS.

Accurate estimation of the potential “upper limit” for extreme precipitation is critical for dam safety and water resources management, as dam failures pose significant risks to life and property. Methods used to estimate the theoretical upper limit of precipitation are often outdated and in need of updating. The rarity of extreme events means that old storms with limited observational data are often used to define the upper bound of precipitation. Observations of many important old storms are limited in spatial and temporal coverage, and sometimes of dubious quality. This reduces confidence in flood hazard assessments used in dam safety evaluations and leads to unknown or uncertain societal risk. This paper describes a method for generating and applying ensembles of high-resolution, state-of-the-art numerical model simulations of historical past extreme precipitation events to meet contemporary stakeholder needs. The method was designed as part of a research-to-application-focused partnership project to update state dam safety rules in Colorado and New Mexico. The results demonstrated multiple stakeholder and user benefits that were applied directly into storm analyses utilized for extreme rainfall estimation, and diagnostics were developed and ultimately used to update Colorado state dam safety rules, officially passed in January 2020. We discuss how what started as a prototype research foray to meet a specific user need may ultimately inform wider adoption of numerical simulations for water resources risk assessment, and how the historical event downscaling method performed offers near-term, implementable improvements to current dam safety flood risk estimates that can better serve society today.

Dams' safety is highly important for authorities around the world. The impacts of a dam failure can be enormous. Models for investigating dam safety are required for helping decision-makers to mitigate the possible adverse consequences of flooding. A model for earth dam safety must specify clearly possible contributing factors, failure modes and potential consequences of dam failure. Probabilistic relations between variables should also be specified. Bayesian networks (BNs) have been identified as tools that would assist dam engineers on assessing risks. BNs are graphical models that facilitate the construction of a joint probability distribution. Most of the time, the variables included in a model for earth dam risk assessment involve continuous quantities. The presence of continuous random variables makes the implementation of discrete BNs difficult. An alternative to discrete BNs is the use of non-parametric continuous BNs, which will be briefly described in this article. As an example, a model for earth dams' safety in the State of Mexico will be discussed. Results regarding the quantification of conditional rank correlations through ratios of unconditional rank correlations have not been presented before and are introduced herein. While the complete application of the model for the State of Mexico is presented in an accompanying paper, here some results regarding model use are shown for demonstration purposes. The methods presented in this article can be applied for investigating risks of failure of civil infrastructures other than earth dams.

State Water Corporation (SWC) is a bulk water supply business which manages a portfolio of large dam structures prescribed under the Dams Safety Act (1978). The Act sets out deterministic criteria to ensure that dam owners apply adequate consideration to dam safety for structures under their control. With limited funding and what may seem to be endless upgrading programs to keep pace with revised hydrology, in recent years dam safety management has moved away from application of traditional deterministic criteria, toward a risk based approach. Risk assessment provides the means to trade off the varying needs of structures in a portfolio, enabling owners to prioritise limited funding resources to areas likely to have the greatest impact and benefit. The process engaged to analyse risk in SWC’s portfolio, and further to develop its capital works upgrading program will be the focus of the following discussion.

Small dams safety issues – engineering/policy models and community responses from Australia