Dam Failure Research Articles

Coupled Continuous-Time Markov Chain–Bayesian Network Model for Dam Failure Risk Prediction

Hydropower dams are critical infrastructure systems characterized by their complex, dynamic, and stochastic behaviors. The frequent variation in the hydrological and meteorological variables poses a higher probability of dam failure, highlighting the need to improve pertinent risk assessment approaches to predict failure risks, considering the uncertain states of such variables. Bayesian networks (BN) analysis has been a key risk assessment tool for decades; however, BN’s static acyclic nature is a recognized drawback. In this paper, a continuous-time Markov chain (CTMC) is coupled with a BN model to enable the dynamic assessment of dam failure risk. In this respect, BN is used to represent the interrelation among the system variables and simulate the propagation of uncertainties throughout the system, whereas the CTMC is adopted to describe the continuous transition of the system variables over their respective states. To demonstrate its applicability, the developed coupled BN-CTMC model was employed to predict the probability of failure of the Daisy Lake Dam in the province of British Columbia, Canada, under the uncertainty of reservoir water level, inflow, and wind speed states. The developed BN-CTMC modeling approach can aid in the development of reliable dam operation schemes and risk mitigation strategies through (1) adequately representing the propagation of the hydrological (e.g., inflow and reservoir water level) and meteorological (e.g., wind speed) variable uncertainties through dam system dynamical processes; (2) effectively quantifying dam failure risk under different operational conditions and failure scenarios; (3) accurately specifying the critical periods of dam system operational safety; and (4) providing in-depth understanding of the relationships between the dam system’s failure and associated variables over time.

Seepage behavior assessment of earth-rock dams based on Bayesian network

Seepage behavior assessment is an important part of the safety operation assessment of earth-rock dams, because of insufficient intelligent analysis of monitoring information, abnormal phenomena or measured values are often ignored or improperly processed. To improve the intelligent performance of the monitoring system, this article has established an assessment framework covering project quality, maintenance status, monitoring data analysis, and on-site inspection based on the relevant norms of seepage safety assessment of earth-rock dams and the expert survey scoring method, and the Leaky Noisy-OR Gate extended model were used to determine the probability of events, and the dynamic and static Bayesian networks used to assess the possibility of seepage failure of earth-rock dams and diagnose the most likely cause of failure. The function of static and dynamic Bayesian networks to assess the seepage behavior of earth-rock dams, abnormal measured values, and causes of anomalies can make up for the limitations of reservoir management personnel and monitoring system in seepage failure experience and seepage knowledge of earth-rock dams and enable better handling of abnormal phenomena and monitoring information, making the monitoring system more intelligent.

The Influence of Internal Erosion in Earthen Dams on the Potential Difference Response to Applied Voltage

Internal erosion is widely perceived as contributing to the failure of earthen dams. To reduce the failure risk, timely monitoring of internal erosion is an effective method in observing their internal structure evolution. A set of earthen dam model experiments were conducted. Under an applied voltage, the response potential differences (PD) at the slope of the dam models were collected before and after the impoundment of the upstream reservoir. The discrepancy among the four dam models, the influence of soil moisture content on PD, and the impact of internal erosion on PD were studied. The results show that it is acceptable to employ different dam models to simulate the development of internal erosion, although the discrepancy among the models is inevitable. The moisture content of the soil significantly affects the PD response to applied voltage. The PD increases with an increase in soil moisture content until the soil is saturated. The change in PD is correlated with the development of internal erosion. With the progression of internal erosion, the starting position for the steep increase in PD distribution continues to move toward the dam toe. In addition, the electrode stability is noted to have an effect on measured PD, which requires further studies to be clarified. This study sets the stage for the PD-based monitoring method in observing the evolution of internal erosion in earthen dams.

Application of Risk-Informed Validation Framework to a Flooding Scenario

In recent years, the use of advanced simulation tools for modeling the behavior of flooding at a nuclear power plant has gained significant importance. The credibility of advanced simulation codes is assessed using formal approaches for verification and validation. In this manuscript, a formal risk-informed validation approach is proposed that provides a basis to quantify credibility of system-level risk assessments. The credibility of system-level validation is represented using a probabilistic metric and maturity levels. The novelty of the proposed approach lies in the integration of risk-informed validation approach with the US Nuclear Regulatory Commission’s (USNRC) Evaluation Model Development and Assessment Process (EMDAP) framework. This allows transformation of EMDAP into a risk-informed EMDAP. The applicability of the proposed framework is evaluated by application to a flooding scenario of a sunny-day dam failure. Application to the flooding scenario illustrates that the credibility of flooding simulations can be assessed using formal quantification, which is otherwise not possible in the existing EMDAP framework.

New solutions for remote monitoring of pre-cast concrete service reservoir and sludge lagoon

The use of distributed temperature and/or strain measurements for embankment and reservoir monitoring has grown in recent years. The paper elaborates on two different methods applied through two installation examples in the UK. To reduce risk, a leakage monitoring system using distributed fibre optic temperature sensing (DTS) with a spatial resolution of 0.7 m has been installed at the newly constructed 45ML Hanchurch Service Reservoir. The gradient method provides information regarding possible seepage by monitoring absolute temperatures over time. Heat pulse method consists of measuring the temperature changes over time using DTS following heating the hybrid cable with a known electrical power input. Central to the £7 million investment on the century-old Curdworth sludge lagoon is the installation of a novel combined leakage and movement of the early detection system. The system is based on distributed fibre optic sensing methods for measuring strain and temperature, both fully automated with a time resolution of about an hour. Instrumentation can be analysed in real time. Trigger levels are being established during a trial period, linked to an automatic alarm system, which supplements site-based surveillance. This will facilitate the early detection of potential embankment/reservoir integrity issues and, in turn, will enable prompt action to be taken to reduce risk and in an extreme case the implementation of essential repairs in order to prevent a dam failure.

The June 2020 Aniangzhai landslide in Sichuan Province, Southwest China: slope instability analysis from radar and optical satellite remote sensing data

A large, deep-seated ancient landslide was partially reactivated on 17 June 2020 close to the Aniangzhai village of Danba County in Sichuan Province of Southwest China. It was initiated by undercutting of the toe of this landslide resulting from increased discharge of the Xiaojinchuan River caused by the failure of a landslide dam, which had been created by the debris flow originating from the Meilong valley. As a result, 12 townships in the downstream area were endangered leading to the evacuation of more than 20000 people. This study investigated the Aniangzhai landslide area by optical and radar satellite remote sensing techniques. A horizontal displacement map produced using cross-correlation of high-resolution optical images from Planet shows a maximum horizontal motion of approximately 15 meters for the slope failure between the two acquisitions. The undercutting effects on the toe of the landslide are clearly revealed by exploiting optical data and field surveys, indicating the direct influence of the overflow from the landslide dam and water release from a nearby hydropower station on the toe erosion. Pre-disaster instability analysis using a stack of SAR data from Sentinel-1 between 2014 and 2020 suggests that the Aniangzhai landslide has long been active before the failure, with the largest annual LOS deformation rate more than 50 mm/yr. The 3-year wet period that followed a relative drought year in 2016 resulted in a 14% higher average velocity in 2018–2020, in comparison to the rate in 2014–2017. A detailed analysis of slope surface kinematics in different parts of the landslide indicates that temporal changes in precipitation are mainly correlated with kinematics of motion at the head part of the failure body, where an accelerated creep is observed since spring 2020 before the large failure. Overall, this study provides an example of how full exploitation of optical and radar satellite remote sensing data can be used for a comprehensive analysis of destabilization and reactivation of an ancient landslide in response to a complex cascading event chain in the transition zone between the Qinghai-Tibetan Plateau and the Sichuan Basin.

Geomorphic processes of a dammed palaeo-lake in the middle Yarlung Tsangpo River, Tibet

The failure of a natural dam is an extreme geological event. Palaeo-lake sediments were discovered in the broad Xigazê valley and Dazhuka-Yueju gorge in the middle reach of the Yarlung Tsangpo River in Tibet. However, the sedimentary processes, dam failure, and peak flood of the Xigazê dammed palaeo-lake are poorly understood. Hence, we conducted a field survey of eight lacustrine sedimentary terraces in the area. We divided the sedimentary processes of the palaeo-lake into five stages and deposit types: pre-palaeo-lake sediments (fluvial or aeolian deposits); early stage sediments of the palaeo-lake (coarse sand); main stage palaeo-lake sediments (clayey silt and sand), sediments following the discharge of the palaeo-lake (sand and gravel-cobbles); and cover deposits (aeolian sediments and colluvium). Additionally, the water level along the palaeo-lake was almost constant (3811 m a.s.l.). The dam was likely located at the eastern end of the Dazhuka-Yueju gorge. Based on the water level, dam location and 30-m ASTER GDEM2 data, the capacity of the palaeo-lake was estimated as 22.55 km3. To separate the water volume and sediment volume, the sediment surface elevation along the palaeo-lake was simulated based on the elevations of the six lacustrine sedimentary terraces. The volume of the sediment was ~11.56 km3, which was calculated from the dam location, sediment surface elevation, and the ASTER GDEM2 data. Finally, subtraction of the sediment volume from the capacity of the palaeo-lake gave a backwater volume of 10.99 km3. The peak flood possibly exceeded 3.4 × 105 m3/s as a moraine dam joined the discharge during the dam failure. However, the dammed event probably had a limited effect on the landforms at downstream because of the presence of another dammed palaeo-lake in the broad Zetang valley; moreover, the bedrock upstream of the dam was protected from erosion.

Dam break analysis using HEC-RAS and HEC-GeoRAS: A case study of Hidkal dam, Karnataka state, India

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 Hidkal dam using a one-dimensional hydraulic model called Hydraulic Engineering Center's River Analysis System (HEC-RAS). HEC-GeoRAS 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 piping and overtopping failure scenarios. HEC-RAS tool is utilized to determine the breach outflow hydrograph and hydraulic conditions at critical downstream locations. Further, the breach outflow hydrographs are routed using dynamic flood wave routing. Further HEC-RAS model is simulated for breach parameters derived from five different empirical methods, and the results are compared. A sensitivity analysis is also carried out to know the variation of peak flow and maximum stage with respect to the breach parameters. The immediate downstream of the dam experience a peak flow of 72,085.45 m3/s and 78,454.82 m3/s and the corresponding inundation area of 75.224 km2 and 79.205 km2 due to piping failure and overtopping failure, respectively. Around twenty village located on the downstream of dam location gets affected due to flood produced by dam break. The analysis shows that overtopping failure is more severe than failure due to piping. The study shall further help authorities concerned to develop an emergency response plan and flood mitigation measures.

A GPU-accelerated Efficient Simulation Tool (EST) for 2D variable-density mud/debris flows over non-uniform erodible beds

Mud/debris flows are among the most challenging gravity-driven flows in environmental and geophysical processes. Natural muddy slurries and debris are solid-laden fluids where the density of the mixture can be more than twice or three times the water density and, hence, the bulk solid phase can represent 40–80% of the flow column volume. Furthermore, these unsteady flows usually occur along steep and irregular terrain which requires a refined non-structured spatial discretization, increasing the computational times of the models. In this work a new upwind Roe-type solver for two-dimensional multi-grain mixture shallow-flow over non-uniform erodible bed is presented. The coupled system of depth-averaged equations is formed by the conservation equations for the mass and momentum of the variable-density mixture, the mass conservation equations for the N different solid phases transported in the flow and the continuity equation for the erodible bed layer, where the different solid phases can be exchanged independently modifying the bed level. The non-Newtonian rheological behavior of the multi-grain mixture is included into the momentum equations using six different basal resistance formulations. An accurate, robust and efficient x-split Augmented Roe (xA-Roe) solver for variable-density flow is derived, which requires a complete reformulation of the averaged-Roe values at the intercell edges and allows the mixture density to participate in the definition of the characteristic wave celerities of the local Riemann problem. The global time step is dynamically controlled by the wave celerities of the coupled system of equations, preserving the scheme stability even for high density gradients. The bed slope and basal resistance source terms are also upwind discretized and included into the intercell numerical fluxes, ensuring a well-balanced flux formulation in steady states and the correct treatment of wet-dry fronts. The proposed model is GPU-accelerated using a CUDA/C++ algorithm and applied to synthetic tests and the USGS debris dambreak experiments over erodible bed, demonstrating its robustness, accuracy and efficiency. Finally, the model is tested against a real-scale and long-term case, the mining-tailing dam failure occured in Brumadinho (Brazil) in 2019. The numerical results show good agreement with the observed field data and the computational cost reduction obtained with the GPU-accelerated algorithm is up to 60 times compared to a CPU-based code.

Experimental and theoretical investigations of seepage reduction through zoned earth dam material with special core

Seepage through earth dams is one of the main causes of failure of earth dams through the internal movement of granules and their transport by seepage. The core in earthen dams has an important role in reducing leakage through the dam body and lowering the phreatic line. In this research, an alternative to the clay soil used in the core of the dam was innovated by conducting multi experiments for testing the permeability of the light-textured, sandy soil which is more available, with additives and it proposed as a suitable alternative. Then the innovative soil model was then used to represent the dam experimentally by means of a permeability device to measure the amount of seepage through the dam body and represent the seepage line. A finite element numerical model using Geo-Studio SEEP/W software was adopted to simulate and investigate soil with different percentages of additives and comparing the numerical and experimental results to predict the innovation model of soil. It was found that the type C sandy soil model has permeability very close to the permeability of clay soils, by using 10% Cement kiln dust (CKD) and 5% cement as additives. Moreover, soil type C was hypothetically tested as a core soil for HIMREEN earthdam of clay core soil. The result of the comparison between seepage for the hypothesis case and the real case was acceptable and they were very close.

The influence of the Doce River mouth on the microbiome of nearby coastal areas three years after the Fundão Dam failure, Brazil

The failure of the Fundão Dam, considered the world's largest mining disaster, released more than 55 million m3 of ore tailings into the environment. The sediment plume formed by water and tailings spread along approximately 663 km of water bodies of the Doce River basin. It reached the Atlantic Ocean sixteen days after the dam failure. However, the effects of the dam failure in the marine coastal areas years after the disaster are still unknown. This study aims to evaluate water and sediment microbial communities of nearby coastal areas three years after the Fundão Dam failure, using 16S rRNA gene amplicon sequencing. A total of 441 samples from 25 locations were collected during two different seasons (dry and rainy). The results showed that the Doce River mouth seems to divide the microbial communities from the southern and northern stations into two groups. The plume of sediments from the Doce River seems to be impacting the marine microbiome even at the furthest sampling stations. Bacterial (Anaerolineaceae, Thermodesulfovibrionia and Rhodopirellula) and Archaeal (Bathyarchaeia and Woesearchaeia) taxa, found in high abundance in the sediment of the Doce River mouth, have been previously described in high abundance in heavy metal contaminated sediments, including the Doce River itself and in mine tailing sediments. Cyanobium, found in great abundance in the water samples from the Doce River mouth, was also reported as the most abundant in the water of the Doce River after the Fundão Dam failure. Overall, the farther from the Doce River mouth the sample was, the lower the relative abundances of these taxa were. These results provide strong evidence that the sediment plume released by the Fundão Dam failure is probably impacting the marine microbiome of nearby coastal areas, even three years after the dam failure.

Seasonality effects on the metal concentration and biochemical changes in Astyanax lacustris (Teleostei: Characiformes) from Doce River after the collapse of the Fundão dam in Mariana, Brazil

This study aimed to evaluate the harmful effects of metal accumulation on Astyanax lacustris and their biochemical response when exposed to the metals contained in the Doce River water, Brazil. The study was carried out in the Baixo Guandu region of the Doce River, Espírito Santo state. Samples were collected during the dry and wet seasons. Biochemical alterations were observed in the liver of A. lacustris, with apparent seasonal effects directly related to the high concentration of Al and Fe in this tissue. Despite this, the bioconcentration of metals in the organisms showed seasonal effects only in the gills, as they are the first organ in contact with the contaminated water. The data generated in this study provide an overview of the health of the ecosystem in this region, highlighting the harmful biochemical and metal concentration effects on the population of A. lacustris affected by the Fundão dam failure.

Flood damage assessment with Sentinel-1 and Sentinel-2 data after Sardoba dam break with GLCM features and Random Forest method

Accurate mapping and monitoring of flooded areas are immensely required for disaster management purposes, such as for damage assessment and mitigation. In this study, the flood damage mapping performances of two satellite Earth Observation sensors, i.e., European Space Agency's Sentinel-1 (S1) synthetic aperture radar (SAR) and Sentinel-2 (S2) multispectral optical instruments, were evaluated using the Random Forest (RF) supervised classification method and various feature types. The study area was Sardoba Reservoir (Uzbekistan) and its surroundings, in which a disastrous dam failure occurred on May 1, 2020. After the failure of a part of the earthfill dam, a large region with settlements and agricultural areas in Uzbekistan and Kazakhstan was flooded. S1 and S2 cloudless data with a short temporal interval acquired soon after the event were available for the area. Four different data availability scenarios, such as (i) only S1 pre- and post-flood data; (ii) only S2 pre- and post-flood data; (iii) S1 pre- and post-flood and S2 pre-flood data; and (iv) S1 and S2 pre- and post-flood data were evaluated in terms of classification accuracy. In addition to the polarization information of S1 and the intensity values of S2 bands, feature maps produced from these datasets, such as vegetation and water indices, textural information obtained from gray level co-occurrence matrix (GLCM), and the principal component analysis (PCA) bands were employed in the RF method. The results show that the fusion of S1 and S2 data exhibit very high classification accuracy for the flooded areas and can separate the inundated vegetation as well. The use of S2 pre-event data together with the S1 pre- and post-event data is recommended for obtaining high accuracy even when post-event optical data is not available.

Dam Safety Emergency Action Plan: A Current Practice for Hydropower Dam in Malaysia

There are currently 104 dams constructed in Malaysia. The dams were built for various purposes; 16 of them were built for hydropower. The dam's reservoir often presents significant risks to downstream areas if a massive downfall release occurs. The enormous downfall could be due to a dam break event, overtopping, and emergency operational release. An incident may occur due to massive flows over a spillway with high-speed discharge or unexpected peak discharge. The obvious impact of the incident is direct to the community in the downstream area. Although there is no dam failure recorded case in Malaysia since the 1900s, the possibility of dam failure occurring is still there. Therefore, the dams must have an emergency action plan (EAP) to prepare the likelihood of the emergency occurrences. This paper aims to explore the EAP practices for dam incident over the region and review the EAP practices of a hydropower dam in Malaysia. Implementing EAP in the emergency response system would minimise the public and environment's impact due to dam failures. The benefit of establishing an EAP is to create better communication and effective responses system among agencies during dam emergency occurrences. This paper revolves around the EAP practices by dam owners in mitigating the risk of dam failure occurrences.

A hydrodynamic model of an embankment breaching due to overtopping flow using FLOW-3D

Embankment dam failures are concerning to many people in the society today, including dam engineers, federal, state, and local officials. The effects of dam failure may cause more harm than good; leading to the losses of lives, properties being damage, economic and environmental downfall. Embankment dam breaching is a complex process between hydraulics and soil erosion processes; until today it still requires more researches to be done. Many factors involved in embankment breaching such as cohesiveness of embankment material, compactness of the embankment soil material, height of the dam and slope of the dam. Through the help of simulation techniques such as computational fluid dynamics, it is possible to understand the behaviour of embankment breaching processes. In this research, modelling of embankment breaching with the aid of FLOW-3D allow us to open doors to plenty of experiments to breaching in the near future. This research focuses in analysing and comparing hydrodynamic parameters; breach outflow hydrograph, peak outflow rate Qp and failure time iy, and geometric parameters; breach depth Hb , and top breach width Bt , of the modelling breached embankment for different sediment diameter and inflow rates. Moreover, the research also investigates the velocity magnitude and breach width during the embankment breaching process.

Utilization of Risk Analysis of Hydraulic Structures for Efficient Allocation of Means

Efficient allocation of available means presuppose detailed knowledge about risks, costs and benefits within the area of interest. The societal demand for increased safety of hydraulic structures, as components of the critical infrastructure, requires considerable investment. To evaluate the effectiveness of potential measures in an environment influenced by epistemic and aleatory uncertainties, risk analysis and cost-benefit analysis are used in practice. The above described approach is now fully implemented when considering natural floods and structural flood protection measures, and also presented in the paper. For potential failures of dams and other important hydraulic structures however the procedure becomes rather more complex to comprehend the effect of designed measures on different failure modes. After introducing governing theoretical principles used for the natural flood vs structural measures analysis, the paper presents examples of application of combination of cost-benefit and risk analysis in the framework of the authors’ work as Strategic Expert of the Ministry of Agriculture of the Czech Republic for the different stages of the flood prevention program. The last part of the paper focuses on dam safety and the application of risk analysis as a support tool for decision making processes. It describes the practice applied in the Czech Republic and comments on the advantages and disadvantages of the current approach while suggesting further possible improvement.

The General and the Specific in the Formation of a Break Wave and the Current Beyond Its Front for Various Cases of Dam Failure

The General and the Specific in the Formation of a Break Wave and the Current Beyond Its Front for Various Cases of Dam Failure

Computer Intelligent Comprehensive Rapid Risk Assessment System of Barrier Dam by Fuzzy Analytic Hierarchy Process and Big Data

Barrier dam overall stability and dam break influence degree are the two risks. In order to comprehensively and quickly evaluate the risk of barrier dams, the dam height, the capacity of the barrier lake and the material composition of the dam body are selected as the stability evaluation indexes; the dam failure degree and the risk population and the potential economic loss are taken as the evaluation indexes. Based on the fuzzy hierarchy theory, this comprehensive and rapid risk assessment system of barrier dam is obtained, which is clear, intuitive and rapid, combining qualitative indexes and quantitative indexes.

Challenges in the Application of Dendrochemistry in Research on Historical Environmental Pollution in an Old Copper Mining Area

This research investigates the long-term environmental impact and historical temporal pollution patterns caused by a former copper mine in Iwiny (south-western Poland) using a dendrochemical approach. An additional aspect of this research was considering the possibility of using the inductively coupled plasma-optical emission spectrometry (ICP-OES) measurement technique as a cheaper alternative to inductively coupled plasma mass spectrometry (ICP-MS) in dendrochemical analyses conducted in copper mining areas. In the study area, a tailings storage facility (TSF) dam failure (1967) took place and the alkaline flotation waste containing high concentration of Cu and Pb are stored. Tree cores from pedunculate oak (Quercus robur L.) were analysed for the content of 11 trace elements (TEs) (Cd, Mn, Ni, Zn, Cr, Co, Pb, Cu, Fe, Al, Ag) using the ICP-OES technique, while tree rings’ widths (TRWs) were also measured. Samples that were most significant in the context of the research goals were verified with the ICP-MS method. The results revealed the strong long-term impact of the copper industry as reflected in a substantial increase in the mean contents of: (1) Mn, Ni, Zn, Cr, Pb, Cu and Fe in industrial vs. control trees, (2) TRWs for control vs. industrial trees. However, the observed patterns of TEs and TRWs did not correspond to the known timing of pollution inputs (mining activity, tailings spill). Peak levels were observed for Zn and Fe after the mine was closed. The lack of new sources of pollution and the temporal relationship strongly suggests that the tree rings recorded the chemical signal of the TSF reclamation (the use of fertilizers and agrotechnical interventions). Patterns of 7 elements were detected in most of the samples by ICP-OES (Co and Cd were not detected, Al and Ag were partly detected), while ICP-MS detected all of the elements. Significant differences were obtained for Ag, Cd, and Co. Despite challenges with the application of dendrochemistry in research on old mining areas (e.g., lack of old trees), it has proved to be a useful tool for investigating the aggregate environmental impact.

Temporal and spatial variations in metals and arsenic contamination in water, sediment and biota of freshwater, marine and coastal environments after the Fundão dam failure

Temporal and spatial variabilities in concentrations of metals (Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) and metalloid (As) associated with the Fundão dam tailings were evaluated in water, sediment and biota from freshwater (tributary, river, lakes and lagoons), marine and coastal (mangroves and beaches) ecosystems affected by the Mariana dam disaster (southeastern Brazil). In freshwater shrimps and fishes, temporal increases in the concentrations of most elements analyzed were observed. This finding was clearly associated with temporal increases in the concentrations of As and metals observed in both water and sediment. In turn, freshwater plankton showed only a temporal increase in Hg concentration, which was also associated with an increased concentration of this metal in the abiotic matrices. In marine fishes, temporal increases were only observed for Cu, Fe and Pb concentrations. Also, temporal increase was observed for Fe concentration in marine plankton (phytoplankton and zooplankton) and shrimps. Marine phytoplankton also showed a temporal increase in Hg concentration. All these findings were clearly associated with temporal increases in the concentrations of these metals in marine sediments. Mangrove crabs showed temporal increases in Hg and Cd, which were associated with temporal increases in water Hg and sediment Cd concentrations, respectively. In turn, beach crabs displayed temporal increases in Mn and Zn, which were associated with temporal increases in the concentrations of these metals in sediments, especially for Mn. In summary, all environmental matrices evaluated in the present study were shown to be contaminated with metals and metalloid associated with the Fundão dam tailings. Additionally, findings reported in the present study relative to the spatial variabilities observed in the whole aquatic area affected by the Fundão dam failure clearly reinforce the need of incorporating biological diversity in monitoring programs aiming to assess environmental health of aquatic systems, considering that patterns of metals and metalloid contamination levels may vary among taxa.