Dam Failure Research Articles

Statistical investigation of reservoir-induced seismic events in mid-Zambezi basin and risk assessment of seismically triggered Kariba Dam failure

Statistical investigation of reservoir-induced seismic events in mid-Zambezi basin and risk assessment of seismically triggered Kariba Dam failure

An Evaluation of Flood Fatalities in Nigeria

Abstract Flood-induced fatalities are among the more poorly reported effects of flood disasters in many developing countries because of poor data inventory and management. Specific objectives of this study are to assess the spatial and temporal variations in flood fatalities in Nigeria, the most populous country in Africa. The study explored available datasets from the National (Nigerian) Meteorological and Emergency Management Agencies as well as those from the Dartmouth Flood Observatory (DFO) at the University of Colorado Boulder and complemented those with scattered reports from Nigerian newspapers to achieve the stated objectives. Using a mix of statistical and geographical information analysis approaches, the study showed that most of Nigeria is vulnerable to flood, given the nature of the dominant climate that often results in “medium” to “high” rainfall intensity (i.e., rainfall = 38.1–50.1 mm or > 50.1 mm in 24 h, respectively), inadequate settlement planning/land-use and land-cover management, and dam failure. Analysis of the frequency of the flood–fatality relationship indicates an increase in flood fatalities by 4.7% relative to flood cases between 1985 and 2017. The study complemented the results with information from newspapers and some other non-peer-reviewed documents (especially reports from relevant agencies) and revealed the need for a better flood information management system in the country, especially since the national database and DFO records were not the same. The study concluded that flood fatalities are on the increase but are poorly reported. It thus recommends improved information systems for flood and other disasters and their fatalities in the country. Significance Statement The purpose of this study is to reveal the state of information on flood disasters in a typical sub-Saharan African country. This is important because information about the distribution and trend of fatalities associated with flood disasters is required for sustainable mitigation planning globally. Our results provide a guide to understanding the distribution and associated factors of flood disasters as well as the contributions of informal (newspaper) sources to the inventory of relevant records.

A multi-platform, open-source, and quantitative remote sensing framework for dam-related hazard investigation: Insights into the 2020 Sardoba dam collapse

Monitoring dam deformation and reservoir conditions plays an important role in routine dam safety assessment. However, maintaining a real-time dam monitoring system and conducting frequent site surveys come with high costs, which may hinder the detection and mitigation of potentially hazardous dam conditions or incident investigations. In view of inaccessibility of in situ data for the scientific community and the need for rapid dam failure hazard investigation, we propose an end-to-end framework that relies on multiple and open-source remote sensing data for the dam-related hazard investigation (RSDHI). The proposed RSDHI framework includes three modules that are capable of monitoring the post-construction deformation status of the dam and the reservoir and provide the first-order and quantitative examination of the hazard causality based on numerical models. We apply and validate the RSDHI framework to a case study of the 2020 Sardoba dam failure in Uzbekistan. We show that the Sardoba Dam experienced continuing subsidence and a local ∼ 4.7 cm differential settlement near the breached section. We reveal that the secondary consolidation controls post-construction deformation. The failure was likely related to the compound effect of transverse structural cracks that resulted from the differential settlement and water loading, yet the exact reason for its failure remains unknown. This study demonstrates that the RSDHI framework can combine multi-sensor remote sensing observations and numerical modeling to provide a complete and up-to-date status report of dam conditions, thereby providing insights into potential instability of dams around the world and enabling rapid investigation of their failures even when no in situ data is available.

Manipulating Disclosure to Repair Corporate Image After an Environmental Disaster: A Study of the Impact of the Dam Failure on Samarco’s Sustainability Reports

Manipulating Disclosure to Repair Corporate Image After an Environmental Disaster: A Study of the Impact of the Dam Failure on Samarco’s Sustainability Reports

Dam Gate Control System using IOT

Abstract: Dams are in the main used for producing hydroelectricity and for irrigation purposes. This utilization has resulted within the construction of a variety of dams in potential areas over the years. As there are plenty of risk factors related to the existence of those dams, it’s became the necessity to develop a correct automatic monitoring system regarding the opening of the dam gates thereby managing a system for maintaining a secure water level in dams. Mismanagement of dams can also bring about manmade disasters. The dams that are present now are monitored and controlled manually. This ends up in pause in deciding. The proposed system involves real-time monitoring of water levels of the dam. Water levels may also range because of drastic adjustments in water levels of linked rivers of lakes, or because of the immoderate rainfall withinside the catchment area. The proposed system is an IoT system which is able to monitor and send real time parameters associated with Dam. The system also includes features like SMS alerts to the people of the locality and higher authorities, live display of water level and also the early-stage crack identification so as to scale back the risks of cracks which can lead to dam failure.

Risk And Disaster Management And Social Inequalities: The Experience of Brumadinho After The Breach of The Córrego of Feijão Dam

Objective: To discuss how vulnerabilities, especially in terms of social inequalities, are linked to disasters and how they become more potent when disasters occur, further aggravating the situation of groups and communities in fragile conditions. Theoretical framework: The Vale dam failure disaster was analyzed from the Disaster Risk Management (DRM) proposal presented by the Sendai Framework, which is based on strengthening actions and measures to prevent disasters, as well as increasing preparedness for responses and recovery from disasters that may occur. Methodology/approach: The method used was the case study. Documentary research, participant observation of WhatsApp groups, and three interviews with representatives of the public sector and civil society were conducted, as well as seven interviews with citizens of Brumadinho. Content analysis was the strategy for data analysis. Main Results: The experience of the municipality of Brumadinho demonstrates how recovery from a disaster is difficult to accomplish and makes the affected population even more vulnerable and exposed to risk, potentiating fragilities and inequalities. Implications of the research: The situation of the city in Minas Gerais highlights the processual construction of disasters and how the current model of economic and productive development needs to be rethought. The criticism of disaster management and the negligence regarding its prevention can serve to guide decisions by the public authorities to develop prevention and damage reduction actions. Originality/value: Empirical studies that discuss the relationship between disasters, vulnerabilities and social inequalities are fundamental to obtain a better understanding of the complexity involved in disaster management, and especially to show how inequalities are enhanced by the occurrence of events of this magnitude, further aggravating the situation of groups and communities in fragile conditions.

Valuation of losses and damages resulting from the Fundão's dam failure: An emergy perspective

In 2015, the ‘Fundão’ dam's failure in Brazil released 44 million m3 of tailings that traveled 670 km in the ‘Doce’ river watershed crossing 40 municipalities and two states until reaching the Atlantic Ocean. Since then, a public civil action (PCA) is responsible for litigation processes, and recently established a value of US$ 43.8 billion to repair losses and damages, a value that brings doubts about its accuracy in expressing the loses and damages of the disaster. This claims for alternative methods for its monetary quantification than the current tradicional economic ones. Among others biophysical approaches, the emergy accounting appears as a powerful tool due to its donor side perspective that objectively quantifies value and recognizes energy quality. This study aims to use emergy accounting as method to firstly identify and then quantify the impacts of ‘Fundão’ dam's failure, considering exclusively the negative direct and immediate impacts. Three categories are considered to quantify loses and damages: (I) suppressed stocks in the mud passage and deposition areas (MPDA), (II) social disruption, and (III) changes in landscape. For all the three scenarios of turnover times (Tt), results show that about 98% of total emergy in the suppressed stocks are related to (II) and (III), while only 2% in average is related to (I). This discrepancy highlights the importance of accounting for (II) and (III) since they are often disregarded or not directly considered by traditional economic approaches. From a macroeconomic perspective, the highest total emergy-based dollars (emdollar, EmUS$) found for scenario #3 reached EmUS$ 149.18 billion, a value 3.4 times higher than the US$ 43.8 billion established by PCA. This higher value is equivalent to the annual emergy demanded by the Ecuador economy with 18 million inhabitants. Rather than providing an accurate monetary value for the ‘Fundão’ disaster repair, this study contributes for the advancement of discussions about using biophysical methods such as emergy accounting that allows tracking all numbers for objective verification as alternative to the traditional economic approaches in quantifying losses and damages of high proportion disasters.

Numerical Simulation on the Evolution of Tailings Pond Dam Failure Based on GDEM Method

Because of the continuous exploitation of metal minerals and the limited availability of land resources, many tailings ponds have been expanded. It is of great importance to dynamically calculate the critical parameters of flooding and sand velocity after a collapse, and quickly determine the dangerous area downstream on reducing the hidden dangers for an accident. In view of the limitations of the single finite element and discrete element methods for the simulation of tailings pond instability, the authors use the finite element and discrete element coupling method (GDEM) for the first time to carry out a dynamical process for numerical simulation of the evolution of a tailings pond collapse. The sediment movement and submerged range were compared with the results of the Volume of Fluid (VOF) method. The comparison shows that the change in drainage flow at the dam foundation position and the depth change in the downstream sensitive point after the dam break are consistent with the VOF calculation results, which indicates that the GDEM can be used as an effective means for the analysis of tailings dam failure. The calculation results of this method can provide technical support for the determination of dangerous areas downstream of tailings ponds and the safety management of key areas.

Discussion on “Procedure for assessing the liquefaction vulnerability of tailings dams”

The stability of tailings dams has become a critical concern for mining industry due to the recent tailings dam failures. The authors have presented a good paper to investigate the failure of tailings dam due to static liquefaction using the commercial FE code Plaix2D. Three procedures that can trigger static liquefaction were investigated in the paper, including surface load, toe deformation, and rise in phreatic surface. However, this discussion presents several simple observations regarding the simulation of the static liquefaction and additional analysis on the Fundão tailings dam.

Why is Brachiaria decumbens Stapf. a common species in the mining tailings of the Fundão dam in Minas Gerais, Brazil?

Currently, more than five years after the Fundão dam failure in Mariana, Minas Gerais, Brazil, Brachiaria decumbens Stapf. is the main grass in pasturelands affected by the mining tailings. The aim of this study was to investigate the reason for this fact as well as to determine the ecophysiological effects of mining tailings on B. decumbens and to test whether mixing the tailings with unaffected local soil enhances the affected soil properties. For the experiment, two different soils were collected, one unaffected soil without mining tailings (Ref) and the mining tailings (Tec), and we also created a mixture with 50 % of each soil type (Ref/Tec). We cultivated B. decumbens in the three soil treatments in a greenhouse for 110 days and evaluated soil physical-chemical properties and plant ecophysiology. Our results show that the tailings (Tec) compromised the normal ecophysiological state of B. decumbens. The species survived these adverse conditions due to its great efficiency in acquiring some elements. The soil management tested by this work mitigated the stress caused by tailings and can represent an alternative for the environmental recovery of the affected soils.

The Piping Failure Mechanism of a Loess Dam: The 2021 Dam Break of the Yang Village Reservoir in China

The construction of a reservoir on a large-thickness collapsible loess cover will significantly increase the occurrence of dam break disasters. The main reason may be that although the gradation of loess particle is not uniform. The clay content is less than 10%. Piping channels easily form under the action of force and collapsibility. Near-static liquefaction of the loess in the dam body under the saturated condition will lead to piping or loss of soil strength. Therefore, it is of great significance to study the mechanical characteristics of loess in the saturated state for preventing dam break. The study investigated the 2021 dam failure of the Yang village reservoir in Ningxia, China, which resulted in millions of dollars of property damage but no casualties. The dam break is a gradual development from piping to complete dam break. This study tries to find out the real reason for dam break from the physical and mechanical properties of the foundation and the dam. We mainly carried out the research through the following three aspects: First, the dam structure was identified by using the seismograph, the compactness of the dam foundation and the dam body was determined according to the wave velocity of the soil layer, and the construction quality of the dam foundation and the dam body was comprehensively evaluated. Second, the particle size distribution confirmed the mechanism of uneven particle size distribution and clay loss. Finally, the undrained characteristics of saturated loess are tested, and the dam failure is essentially explained. The research results show that using this loess to fill the dam foundation directly and the dam body has a very high probability of piping-type dam failure. This study gives some design suggestions for using this loess for dam building, for example, through the design of the filter layer to increase the difficulty of piping occurrence.

Dam Break Analysis using HEC-RAS: A Case Study of Karjan Dam

A dam is a structure constructed across river which stores water and supplies water for various purposes. Though the dams have many benefits, there is always a threat of dam break floods which are devastating in nature. Hence it becomes essential to analyze and simulate dam failure scenarios to understand the severity of dam break flood and identify areas under threat which helps in land use planning and developing emergency response plans. This study attempts to carry out dam break/breach analysis for the Karjan dam using a two-dimensional hydraulic model called Hydraulic Engineering Center’s River Analysis System (HEC-RAS). RAS-Mapper tool is used to extract river geometry data from the Cartosat-1 digital elevation model (DEM) and to generate the inundation map to identify the areas affected. The study involves the prediction of breach parameters, breach flood hydrograph, peak flow, flood arrival time, and generation of inundation maps. The dam break model is simulated for unsteady flow conditions using Probable Maximum Flood (PMF) corresponding to different failure scenarios. HEC-RAS tool is utilized to determine the breach outflow hydrograph and hydraulic conditions at critical downstream locations. The outcome will assist the local government in making proper planning and development decisions. Key Words: Arc-GIS, Dam break analysis, Karjan dam, Flood Inundation, HEC-RAS

STABILITAS DAN DEFORMASI PADA TANAH LEMPUNG LUNAK DI BENDUNGAN TERITIP

Dams on soft soils differ greatly in behavior when compared to rock foundations. Potential dam failures can occur due to differential settlement. The total reduction in Barnacle dam without PVD takes 17 years. Analysis of the use of PVD shows an increase in shear strength due to dissipation of pore stresses marked by an increase in safety figures. The time needed to achieve consolidation of at least 80% is 180 days based on finite element simulations. The total reduction in the body of the dam is 1.37 meters.

Mineralogical Fingerprint of Iron Ore Tailings in Paraopeba River Bedload Sediments after the B1 Dam Failure in Brumadinho, MG (Brazil)

The study presents SEM-based automated mineralogy to distinguish between natural sediments and iron ore tailings deposits from the Paraopeba River, after the failure of B1 Dam in Brumadinho, Minas Gerais, Brazil. Samples were obtained from borehole cores drilled over channel bars and banks eight months after the failure. After preliminary facies description, sediments from 54 chosen intervals were subjected to density measurement, X-ray diffraction (XRD), SEM-based automated mineralogy (QEMSCAN) analysis and determination of geochemical major components. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) revealed six main mineral associations governed by different contents and ratios of quartz, kaolinite and hematite. Natural sediments are predominantly composed of mineral associations containing kaolinite, quartz and quartz + hematite with density values ranging from 2.5 to 3.3 g/cm3. Tailings deposits have density values higher than 3.5 g/cm3 and are mainly composed of hematite with occasional occurrences of kaolinite + hematite. Because of geological complexity and historical terrain occupation and usage, geochemical anomalies are common in the Paraopeba River sediments. Our data suggests that mineralogical oriented studies should precede detailed geochemical investigations, to enhance the understanding of the source of such anomalies and the environmental jeopardy associated to the occurrence. In this sense, SEM-based mineralogy has an enormous potential in environment studies.

3D numerical simulation of seismic failure of concrete gravity dams considering base sliding

Abstract The sliding of dam base along dam-foundation rock interface during earthquake excitation can decrease the earthquake response of the dam. The present study reveals a numerical simulation of the seismic failure response for Oued Fodda concrete gravity dam, located in northwest of Algeria, considering base sliding. Nonlinear finite element analyses are performed for Oued Fodda damfoundation rock system. The Smeared crack approach is used to present cracking of dam concrete under the 1980 El Asnam earthquake (M7) using Willam and Warnke failure criterion. The hydrodynamic pressure of the reservoir water is modeled as added mass using the Westergaard approach. The sliding behavior of contractions joints is modeled by surface-surface contact elements that provide the friction contact at dam-foundation interface. Drucker-Prager model is considered for dam concrete in nonlinear analysis. According to numerical analyses, several cracks may appear due to tension particularly at middle upper parts located along the symmetry central axis of the dam in both upstream and downstream faces. Although the dam sliding on its foundation reduces the magnitude of principal tensile stresses in dam body; however, the reduction magnitude is generally not large enough to preclude the cracks propagation in dam body.

PENILAIAN RISIKO BENDUNGAN SAGULING DENGAN METODE TRADISIONAL, METODE POHON KEJADIAN DAN METODE MODIFIKASI ICOLD

The role of dam infrastructure must be ensured from management and maintenance through good operational and maintenance provisions as to maintain level of service provision, extend life of productive assets and reduce risk of dam failure. Dam risk assessment can be used to prioritize dams based on risks. Risk assessment consists of risk analysis and risk evaluation. Purpose of this study is to conduct a risk assessment on Saguling Dam using traditional methods, event tree methods and ICOLD modification method to get an overview safety condition Saguling Dam. In conducting risk evaluation for ICOLD modification method, evaluate by comparing value of risk index to risk class. results of the risk identification analysis of this study that risk assessment using traditional method shows that risk of the Saguling Dam is unacceptable because this method does not describe each possibility in detail. Risk assessment using the event tree method shows that the risk of the Saguling Dam is acceptable. Risk assessment using the modified ICOLD method shows that the Saguling Dam belongs to category of Dam with moderate risk.

Seepage Analysis of Core Section of Jhuj Dam

Abstract: Zoned type Earthen dams are the type of Rolled fill Earthen dam because the soil is compacted by mechanical rollers in thin layers of 20-30 cm having central impervious core surrounded by shell as pervious material. These dams made since early days of civilization and constitute to be the most common type, because it is generally built of locally available soils proved to be most economical. The soil used in earthen dam are suspectable to seepage through the body of dam due to their permeability. Due to seepage soil gets reduces its strength and failures of dam may occurs. Past studies on earthen dam failures concluded that about 30% of dam failed due to seepage. An impervious central core is used in zoned type earthen dam to reduce the seepage quantity through the body of the dam and protects against the seepage failure of dam like piping and sloughing. Earthen dams are vulnerable to failures due to seepage that take place in the core since all soils are pervious to some extent. One of the best ways to control seepage problem in earthen dam is by using proper impervious soil for core section which provides the water tightness to flow through it. Thus, this paper analyses the usage of locally available soils with different combinations with central impervious vertical core and to study the seepage discharge by using Darcy law. The results obtained from the study is compared with actual seepage data obtained with existing soil in central core. Keywords: Impervious core, Permeability and Seepage, Smear effects, Phreatic line, Flow net

Validation of an Empirical Model with Risk Assessment Functionalities to Simulate and Evaluate the Tailings Dam Failure in Brumadinho

The failure of tailings dams causes ecological damage and economic loss and can cause casualties. The simulation of the tailings’ spill path in the event of tailings dam failures (TDFs) can mitigate the risk by the provision of spatial information for disaster prevention and preparedness. In order to close the gap between basic one-dimensional spill-path routing models and complex numerical models, this paper examines an empirical model based on the freely available Laharz model. The model incorporates a tailings-specific planimetric area regression from the literature to describe the spatial extent of tailings flows based on the released volume. By providing information about affected residents and infrastructure, such a model can be used for preliminary risk evaluation. The model was validated against the TDF in Brumadinho (2019) and reached hit rates of over 80%, critical success indices of approximately 60% and false alarm ratios of roughly 30%. The latter is particularly evident in the overestimation of the lower part of the tailings flow. The risk assessment identified 120 affected residents, 117 destroyed buildings (109 reported) and several kilometres of affected roads (1.9 km) and railway (2.75 km). However, the OpenStreetMap-based part of the risk assessment inherits some uncertainties to be investigated in the future.

Risk Evolution Study of Tailings Dam Failures Disaster Based on DEMATEL-MISM

Tailings pond engineering is a complex and extensive system with many risk factors that can trigger a dam failure. It is important to clarify the evolutionary relationships among the factors and to enhance effective management to reduce the risk of dam failure. In this paper, an effective and reliable method for analyzing the evolution of tailings pond dam failure risk by combining DEMATEL and MISM is proposed. Firstly, 35 risk factors affecting tailings pond failure were summarized. An index system for evaluating the imfluence factors of dam failure was constructed from four aspects: personnel, management, environment, and system. Secondly, the Decision-making Trial and Evaluation Laboratory (DEMATEL) was used to study the influence relationships among the factors, for analyzing and identifying the key causal factors. Subsequently, the Modified Interpretative Structural Model Method (MISM) was used to classify the cause factors into five levels of influence as well as to determine the degree of integrated influence between the risk factors. Finally, an evolutionary model of tailings pond dam failure risk was constructed based on the results of the analysis. The results of the study indicated the followings: 1) System risk accounted for 58.58% of the total weight, while personnel risk accounts for 15.51%. To maintain the stability of the tailings pond system, personnel risk should not be neglected in addition to focusing on systemic factors. 2) Rainfall intensity was an essential causal factor. Focusing on rainfall intensity and taking appropriate measures effectively reduced the risk of dam failure. The height of the dam and the depth of the seepage line accounted for a large proportion of the causal factors, making it possible to control the height of the dam and accurately monitor the depth of the seepage line to improve the stability of the dam. 3) In the tailings pond dam risk evolution model, there were 30 factors with higher mutability and correlation, which played a transitional role in risk transfer. A risk factor transfer network diagram was established for this purpose as a diagnostic map. The research results can provide new methods and ideas for tailings dam failure risk analysis research and practice.

Regional Distribution and Causes of Global Mine Tailings Dam Failures

Tailings ponds are one of the three major production facilities in metal mines. The volume of tailings increases year by year, but the storage capacity of existing tailings ponds is limited. Therefore, tailings dams must become more fine-grained and larger. The potential hazard they represent should not be underestimated. This paper reveals the causes and regional distribution patterns of 342 tailings dam failures globally from 1915 to 2021 through statistical analysis. It was found that tailings pond failures occur almost every year, with an average of 4.4 accidents/year (1947–2021). The frequency has been gradually increasing in recent years, and most tailings pond failures are directly related to heavy rainfall or earthquakes. The frequency of tailings pond failures was significantly higher in Asia (21.3%) and the Americas (57.9%), especially in China (n = 43) and the United States (n = 107). Causes of tailings pond failures differed among regions. Most tailings pond failures in Asia and Europe were related to hydroclimate, while those in South America were mainly triggered by earthquakes. This study will provide theoretical data for the pre-design as well as the safe and stable operation of global tailings ponds, which will help to prevent global tailings pond failures.