Dam Breach Research Articles

Variation in sediment sources and the response of suspended sediment grain size in the upper Changjiang River Basin following the large dam constructions

The amount, patterns, and particle size composition of suspended sediment in the upper Changjiang Basin has been altered significantly due to the cascade reservoirs construction. A dam breach may disrupt sedimentation in the reservoir, channel erosion downstream of the dam, and the cycle of nutrients and contaminants adherent to the dam. This study is based on the long time-series field data of water discharge, sediment flux, and suspended sediment grain size of the upper Changjiang River Basin from 1973 to 2019. Four significant stepwise reduction periods in sediment load were identified by employing the M-K test, namely, 1973–1992, 1993–2002, 2003–2012, and 2013–2019. Based on the results, sediment load reduction in the upper Changjiang River (CJR) is remarkably correlated with an increase in the capacity of large reservoirs. Jialingjiang River became the largest sediment source area for upper CJR in 2013–2019. Moreover, the variation range of suspended sediment median particle size gradually narrowed with decreasing sediment load during the four periods in the upper CJR. The silt content of suspended sediment increased while clay and sand contents decreased which would maybe a factor of decreasing of P flux in the upper CJR. After the impounding of the Xiangjiaba and Xiluodu Reservoirs in the Jinshajiang River, the fining trend of suspended sediment along the main stem of upper CJR was cut off in 2013–2019, which may be ascribed to sediment management of the cascade reservoirs regulation and the sediment resuspension from the channel erosion in the river downstream. These observations can also serve as a reference for future studies about the effects of cascade reservoirs on aquatic ecology and environmental changes.

Legacy sediment and stream incision in the North Carolina Piedmont: Fluvial evolution before and after mill dam construction

Streams in the southern Piedmont are consistently incised forming deep (∼ 1–3 m) channels within wide valley bottoms. Here, we use a variety of methods to determine the drivers of stream incision in the region. We mapped ∼ 140 historic dams throughout the region since the breaching of mill dams is a known driver of incision elsewhere. We examined stream banks at 20 sites previously dammed and 8 sites with no known dams. At each site, we measured channel depth, described sediments, and dated sedimentary charcoal via radiocarbon dating. We also examined historical aerial photographs and used modern LiDAR to create cross-sections in multiple locations. Our findings indicate that while dams were common throughout the area, they were typically built within the incised streams indicating that incision predates dam construction. Locally, incision appears to have been part of an aggradation-degradation sequence driven by a period of Euroamerican deforestation. Most dams in the region are reported to have been built before 1850 indicating relatively early incision in the region. The legacy sediments overlie Holocene sediments that are similar to those in anastomosing systems that remain in a few stream reaches today. As such, anastomosing systems may have been common in the region during the Holocene. Both legacy sedimentation and erosion appear to continue into the present with alluvial sedimentation, stream straightening, headward erosion, and now a new discharge regime driven by urbanization in the region. Broadly, our results suggest that streams in the southern Piedmont have been consistently impacted by humans since Euroamerican settlement.

Future projections of worst floods and dam break analysis in Mahanadi River Basin under CMIP6 climate change scenarios.

This study provides a comprehensive analysis of the hydrological effects and flood risks of the Hirakud Reservoir, considering different CMIP6 climate change scenarios. Using the HEC-HMS and HEC-RAS models, the study evaluates future flow patterns and the potential repercussions of dam breaches. The following summary of the work: firstly, the HEC-HMS model is calibrated and validated using daily stage-discharge observations from the Basantpur station. With coefficient of determination (R2) values of 0.764 and 0.858 for calibration and validation, respectively, the model demonstrates satisfactory performance. Secondly, The HEC-HMS model predicts future flow for the Hirakud Reservoir under three climate change scenarios (SSP2-4.5, SSP3-7.0 and SSP5-8.5) and for three future periods (near future, mid future and far future). Thirdly, by analyzing time-series hydrographs, the study identifies peak flooding events. In addition, the HEC-RAS model is used to assess the effects of dam breaches. Downstream of the Hirakud Dam, the analysis highlights potential inundation areas and depth variations. The study determines the following inundation areas for the worst flood scenarios: 3651.52 km2, 2931.46 km2 and 4207.6 km2 for the near-future, mid-future and far-future periods, respectively. In addition, the utmost flood depths for these scenarios are determined to be 31 m, 29 m and 39 m for the respective future periods. The study area identifies 105 vulnerable villages and several towns. This study emphasizes the importance of contemplating climate change scenarios and implementing proactive measures to mitigate the peak flooding events in the Hirakud reservoir region.

Calculation formula and coefficient analysis of dam breach discharge based on surface velocity

In previous studies, a new formula Qout=Cdg−1B‾us3 was proposed to estimate the discharge of a breaching dam based on water flow surface velocity. To determine the range of the discharge coefficient Cd and the optimal application position in an actual dam breach event, this paper used experimental and statistical methods for further investigation. First, the sensitivity and influencing factors of the new discharge coefficient were discussed. Second, the distributions of the surface velocity in the x and y directions and the resultant velocity along the breach width direction were analyzed, and the spatial and temporal distributions of maximum surface velocity and average surface velocity were compared. Third, the surface velocities of four sections were substituted into the new flow formula, and the range of the new discharge coefficient was analyzed using regression fit. Finally, the correctness of the value range of the new flow formula was verified by inverting Tangjiashan landslide dam data. The results indicate that the influence of the calculated section position (Froude number) was less than that of the average flow velocity coefficient k2 on the discharge coefficient. Based on the maximum surface velocity, the flow formula can be approximately transformed to Qout=Cdg−1B‾(βums)3. The reasonable ratio of the average surface velocity to the maximum surface velocity in the formula was 0.550≤β≤0.749, and the discharge coefficient falled within 0.373≤Cd≤0.645.

Retraction notice to “Investigating the peak outflow through a spatial embankment dam breach” [Ain Shams Eng. J. 13(6) (2022) 101799

Retraction notice to “Investigating the peak outflow through a spatial embankment dam breach” [Ain Shams Eng. J. 13(6) (2022) 101799

Non-Equilibrium Bedload Transport Model Applied to Erosive Overtopping Dambreach

Bedload sediment transport is an ubiquitous process in natural surface water flows (rivers, dams, coast, etc), but it also plays a key role in catastrophic events such as dyke erosion or dam breach collapse. The bedload transport mechanism can be under equilibrium state, where solid rate and flow carry capacity are balanced, or under non-equilibrium (non-capacity) conditions. Extremely transient surface flows, such as dam/dyke erosive collapses, are systems which always change in space and time, hence absolute equilibrium states in the coupled fluid/solid transport rarely exist. Intuitively, assuming non-equilibrium conditions in transient flows should allow to estimate correctly the bedload transport rates and the bed level evolution. To get insight into this topic, a 2D Finite Volume model for bedload transport based on the non-capacity approach is proposed in this work. This non-equilibrium model considers that the actual bedload sediment discharge can be delayed, spatial and temporally, from the instantaneous solid carry capacity of the flow. Furthermore, the actual solid rate and the adaptation length/time is governed by the temporal evolution of the bedload transport layer and the vertical exchange solid flux. The model is tested for the simulation of overtopping dyke erosion and dambreach opening cases. Numerical results seems to support that considering non-equilibrium conditions for the bedload transport improves the general agreement between the computed results and measured data in both benchmarking cases.

Determining recovery of marine water quality of the Rio Doce using statistical and temporal comparisons with nearby river systems.

The Fundão dam breach affected the Rio Doce's estuarine and marine environments with water, tailings, scoured soil and/or sediments, and other debris. Time series and standard exceedance analyses are typically used to assess water quality recovery to baseline conditions after deteriorating water quality events. In the absence of historical measurements, impacts to water quality from the Fundão Event were compared with measurements of nearby rivers. Similar river systems with available water quality measurements were grouped into affected and unaffected estuarine and marine waters. Statistical and temporal comparisons of marine waters unaffected by the Rio Doce with those affected by the Rio Doce were evaluated for systematic differences. Multivariate statistical techniques were also used to assess water quality differences. Our results demonstrate that the Fundão dam breach had a short-term water quality impact on marine waters near the Rio Doce mouth. Principal component and comparative time series analyses clearly demonstrated this impact during the 2015/2016 and 2016/2017 wet seasons. The ephemeral effects of the breach, however, did not compromise marine water quality. Exceedances of CONAMA standards for metals remained either at zero or at very low levels during the affected period (<5.7%). Before the start of the next wet season in October 2017, water quality impacts from the Event were statistically indistinguishable from unaffected marine waters, indicating recovery to baseline conditions. Integr Environ Assess Manag 2024;20:99-116. © 2023 NewFields Companies, LLC. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Review on model development techniques for dam break flood wave propagation

AbstractCatastrophic failure of dam structures has often led to severe consequences. The colossal wave receding at a higher velocity from the sudden failure of the dams may obliterate the downstream areas causing loss of lives and property damage. Thus, proper mitigation measures and contingency plans must be formulated beforehand to minimize the impact of such disasters. Consequently, there has been a strong tendency to study dam breach flood modeling using different approaches for both hypothetical dam breach scenarios and real incidents. The technology used for dam breach studies is advancing and a comprehensive review of the existing methodologies would help the modelers in their model development. This paper reviews the state‐of‐the‐art methodologies utilized in studies to propagate the dam break flood wave. Furthermore this guides the selection of methods best suited considering the project‐specific requirements and the complexity of project to simulate the risk to the vulnerable areas generated from the dam break flood flow. Different terrain datasets, mesh generation techniques and calibration techniques have been adapted and adhered to improve computational accuracy, stability and efficiency in modeling dam break floods. The use of high‐resolution global and site‐specific datasets, subgrid models, the choice of roughness coefficients and high‐resolution time steps have to be investigated thoroughly in these models. The paper reviews the existing methodologies with the strengths and limitations facilitating the future dam breach modelers to select the suitable approach in dam break flood wave modeling.This article is categorized under: Engineering Water &gt; Sustainable Engineering of Water Science of Water &gt; Water Extremes Water and Life &gt; Conservation, Management, and Awareness

Applying multivariate techniques to fingerprint water quality impact of the Fundão Dam breach within the Rio Doce basin.

The Fundão Dam breach on 5 November 2015 (the "Event") released tailings, water, soil and/or sediments, and other debris to downstream watercourses. This breach included both direct and indirect impacts from scouring of soils and sediments along and within the affected courses. Multivariate statistical techniques were used to determine the potential of fingerprinting the impact of the breach compared to pre-Event water quality conditions and unaffected watercourses. The selection of key parameters is an important first step for multivariate analyses. Analysis of too many parameters can mask important trends and relationships, while analysis of too few may miss significant water quality indicators. A two-phased selection process was used to identify key parameters that indicated impact from the Event: (a) unbiased, principal component analysis to extract chemically dominant profiles among all measured parameters and (b) comparison of metals' concentrations between unaffected soils and/or sediments and tailings samples. Radar charts of key parameters along with statistical comparisons to pre-Event and not-affected waterways were then aggregated over space and time to assess impact and potential recovery to pre-Event conditions. Nine parameters were identified that characterize tailings-related (direct) and background soil and/or sediment-related (indirect) impacts. Spatially and temporally aggregated radar charts and nonparametric Mann-Whitney U tests were used to assess the statistical significance of these impacts during each wet season since the breach. Indirect parameters, like aluminum and lead, returned to pre-Event levels in the first wet season after the Event. By the 2018/2019 wet season, most of the direct and indirect parameters had returned to pre-Event levels. Integr Environ Assess Manag 2024;20:133-147. © 2023 NewFields Companies, LLC. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Probabilistic Analysis of Floods from Tailings Dam Failures: A Method to Analyze the Impact of Rheological Parameters on the HEC-RAS Bingham and Herschel-Bulkley Models

The difficulty in determining the rheological characteristics of tailings inside reservoirs as well as their intrinsic variability adds uncertainty to tailings dam failures in flood studies. Uncertainty propagation in non-Newtonian hydrodynamic models stands as a great scientific challenge. This article explores the sensibility of tailings dam breach flood mapping to rheological parameters in Bingham and Herschel-Bulkley (H-B) models. The developed approach was based on the probabilistic Latin Hypercube Sampling of rheological parameters. It was automated to propagate uncertainty throughout multiple hydrodynamic simulations using the HEC-RAS v.6.1 software. Rheological parameter ranges and distributions were based on a broad bibliographic review. Bingham models were revealed to be more sensitive than H-B in terms of simulated min-max area values: for Bingham, flood areas, maximum depths, and arrival times varied by 17.9%, 9.3%, and 8.2%, respectively; for H-B, variations were 25.7%, 5.1%, and 3.9%. However, Bingham was less sensitive in terms of hydrodynamically associated probability: high probability ratios were related to a small range of simulated areas in Bingham, while H-B presented great variability. Finally, for each model, the parameters that affect uncertainty the most were identified, reinforcing the importance of determining them properly. Furthermore, the identified parameter ranges for both models should be valuable for defining variable value boundaries for flood sensitivity tests on specific tailings materials for other case studies. The automated algorithm can be used or adapted for specific tests with other hydrodynamic simulations.

A window into development of a complex ice-marginal lake prior to the Late Glacial Maximum (LGM) in Austria

Abstract Although the retreat process of glaciers from the Late Glacial Maximum (LGM) is well documented, high-resolution insight into conditions prior to the maximum is lacking in the eastern European Alps, resulting in a gap in our understanding about the processes associated with this important climatic tipping point. We describe an outstanding sand and gravel outcrop at Gröbming in the Enns Valley (Ennstal), Austria, that represents the development of a delta complex that debouched into a large body of water that we name paleo-Lake Gröbming, fed by a major valley glacier. The succession consists of sands bearing climbing ripples, parallel laminations, and supercritical bed forms (bottomsets) overlain by meter-scale gravelly foresets. Topsets comprise gravels. We argue that sustained accumulation of supercritical bed forms required a jet efflux feeder mechanism best explained by a direct glacial meltwater source. Complex vertical and lateral repetition of this tripartite succession is observed, with sequence stratigraphic analysis permitting us to argue that stratal complexity is attributable to base-level changes in paleo-Lake Gröbming resulting from dam breaches of the lake. Thus, application of well-established sequence stratigraphic approaches to Quaternary ice-marginal successions in the Alps has significant potential to yield unprecedented insights into conditions prior to the LGM.

Physical and numerical modeling of the hypothetical tailings dam breach runout and mitigation with a slurry-resisting barrier

Physical and numerical modeling of the hypothetical tailings dam breach runout and mitigation with a slurry-resisting barrier

Simulation of dam-break flood and risk assessment: a case study of Chengbi River Dam in Baise, China

Abstract When a reservoir is damaged, it will bring destruction to people's lives and the regional economy. Flood simulation and risk assessment are two effective ways to mitigate flood risk. Flood risk is assessed by using flood hazard and vulnerability indices. However, one of the key concerns is how to quantify hazards and vulnerabilities more rationally. To this end, this study introduces a new quantitative method for flood risk assessment. Three schemes – full dam breach (S1), 1/2 dam breach (S2), and 1/3 dam breach (S3) – were proposed for flood simulation. HEC-RAS 2D was used to simulate the evolution process of dam-break floods. This study used a new quantification approach to calculate flood risk based on simulation results. The results show the following: (1) The inundation process is similar under the three schemes, but the degree differs. The greater the degree of dam break, the greater the inundation depth, maximum flow velocity, and inundation duration. (2) High-risk areas decrease with decreased dam break degree. Under the three schemes, the flood risk areas of Longjing Street account for 65.37, 71.41, and 66.22% of the total risk areas, respectively, which are the areas most affected by dam-break floods.

FIBRADIKE, a novel distributed fiber optic monitoring system for dikes and earth dams

Safety issues related to climate change are one of the major challenges of modern society. One of the most significant risks is represented by extreme flood events which could lead to dike or earth dam breaching with catastrophic consequences for the environment. Despite the relevance of these infrastructure and modern advanced sensing technologies, dike and earth dam safety monitoring is carried out as it has been for centuries with visual inspections. In the best case, traditional point sensors, like piezometers, are installed in some limited sections. In this way it is not possible to early identify problem sections, which can be located many km away from the observation point. In this research an attempt has been made in order to develop a distributed fiber optical sensing system for dike and earth dam safety monitoring. The core of the system is represented by a novel distributed pore water pressure sensing unit, in the form of a specifically designed fiber optic sensing cable.. The development and first promising results of laboratory testing carried out on the industrially produced prototypes of the sensing cable are presented in this paper.

Global Sensitivity Analysis of a Dam Breaching Model: To Which Extent Is Parameter Sensitivity Case‐Dependent?

AbstractFailure of dams and dikes often leads to devastating consequences in protected areas. Numerical models are instrumental tools to assess flood risk and guide emergency management, but numerous uncertainties affect model outcomes. Identifying uncertain model input parameters that induce high uncertainties in model outputs is essential. This paper focuses on two model outputs: the maximum breach discharge and the time to reach this peak. Using our implementation of a simplified physically based dam breaching model developed by Wu (2016), a global sensitivity analysis was conducted based on Sobol indices of total order. Unlike in most previous studies, many different configurations (twenty‐seven), both at laboratory and field scales, were considered. For each of them, input variables were ranked according to the significance of the contribution of their uncertainty to the output variability, and the dependency between reference configurations and sensitivity analysis results was highlighted. Depending on the considered case study, input parameter uncertainties with the largest impact on output variability were different, and so was the magnitude of output uncertainties. We demonstrate that sensitivity analysis results obtained for a specific configuration cannot be transferred as it to other configurations. Finally, sensitivity and uncertainty quantification results were combined in a decision tree to determine which input parameter uncertainty is the most critical in each configuration and what standard deviation in the output variables is expected. The global sensitivity analysis procedure presented here may apply to a wide variety of models in environmental sciences.

River blockage and impulse wave evolution of the Baige landslide in October 2018: Insights from coupled DEM-CFD analyses

On 11 October 2018, the Baige landslide in Southwest China blocked the Jinsha River and induced waves amplifying the landslide-affected area significantly. Devastating flood damage was caused by the consequent dam breach. Such a complex sequence can lead to catastrophic consequences but has rarely been fully reproduced. This paper investigates the landslide-river interaction of the first Baige landslide based on coupled discrete element method (DEM) and computational fluid dynamics (CFD) analyses. To this end, the volume of fluid (VOF) and virtual sphere model are adopted to realise impacted river tracing and accurate terrain modelling. The damming process and impulse wave evolution of the first event are well represented. In addition, the simulated cumulative landslide spreading path, deposit geometry, maximum wave elevation and cumulative wave erosion area satisfactorily match the survey results. Our findings further indicate that the movement path and deposit morphology of the Baige landslide are mainly affected by local terrain, while the propagation of impulse waves is driven by the sliding mass and modulated by the riverbank and hydrodynamic conditions. In particular, we discussed the evolution patterns of impulse waves caused by river damming landslides, encompassing run-up on the opposite bank and quasi-3D propagation along the river direction. This research provides a valuable guide for the practical simulation of river blockage and impulse wave evolution and supports the mitigation of landslide disasters in mountainous areas.

Identifying and testing the probability distribution of earthfill dam breach parameters for probabilistic dam breach modeling

AbstractThe main goal of this study is to identify the probability distribution of earthfill dam breach parameters using a dam failures database (3861 observations). This work looks to fill the lack of studies observed, using an extensive database instead of empirical models, plausible values, or small databases. It is, expected that this will contribute to the development of probabilistic dam breach inundation maps instead of deterministic mapping. Four parameters were selected: (i) side slope, (ii) height, (iii) width, and (iv) formation time. To identify the best‐fit distributions, a correlation analysis was performed and a comparative analysis was undertaken by groups related to dam and failure properties such as dam type, material erodibility, magnitude, failure mode, and others. These steps defined samples with 33–311 observations. The results demonstrate that dam breach parameters might be considered independent of each other and are affected by factors such as side slope by failure mode and bottom width by dam shape. The probabilistic case study indicated that deterministic dam breach models predominantly produce conservative results of breach peak outflow.

Impact of Dam Materials and Hydraulic Properties on Developing the Breaching Dimensions

Dam safety is an important issue as it directly influences environmental and life losses. Embankment material and embankment core are important factors that contribute to determining the size and hydraulic characteristics of the breach that occurs due to dam failure. The current topic is to present the analysis of the impact of the dam materials properties and hydraulic characteristics on breach dimensions due to overtopping failure using 2D-HEC-RAS software with the aid of RAS-Mapper. The analysis was made by Digital Elevation Model (DEM) conversed to a Triangular Irregular Network (TIN), then the 2D area of the dam was determined and the storage area boundary was calculated. Mosul dam in Iraq, considered one of the big dams that consist of different materials in the core and body, was selected as a case study to simulate the dam breach development due to overtopping failure. Six scenarios of dam failure were carried out for three types of dam materials (dam with corewall, concrete-face dam, and homogeneous zoned fill dam), each with high and medium erodibility. All scenarios were made for the reservoir elevation of 341 m which is considered the probable elevation for failure occurrence. The results showed that the minimum and maximum values of breach width were found to be 542 m and 1118 m, respectively in both cases of concrete-face dam type with a high erodibility and homogeneous zoned fill dam with medium erodibility rate. It has been illustrated that the medium erodibility in each scenario gives a smaller width for a long time, especially in homogeneous zoned fill dam type which is a good indication in engineering design. The analysis of sensitivity was carried out to examine the impact of pool volume at failure on breaching time and width of the breach. It showed that the breach width is more sensitive to reservoir fill capacity and there is a linear relationship between water volume reduction ratios and the breach width. Finally, tests of the six cases reveal that the proposed model is sensitive to soil conditions.

A Low-Cost, UAV-Based, Methodological Approach for Morphometric Analysis of Belci Lake Dam Breach, Romania

The greatest challenges encountered in geospatial studies are related to the availability, accuracy, relevance and cost of the data used. The main mapping techniques currently employed are based on digital data, which are used to create digital elevation models (DEMs). The aim of the present study is to devise and apply methodologies for the generation and validation of high-resolution mapping materials, usable both for local, large-scale analyses, and for the calculation of certain morphometric parameters based on structure from motion (SFM) techniques, applied to images acquired by means of a drone at low cost. As a case study, the ruins of the Belci dam, located in Romania, were analysed, where, with the help of a drone, GIS measurements were performed on the arborescent vegetation of the study area, and a digital terrain model (DTM) of the dam was generated. The costs of such a methodological endeavour are low, which allows for the repetition of the steps involved in devising the maps necessary for such studies on a weekly, seasonal, or annual basis, or after extreme events (floods, landslides etc.). The cartographic materials created in the present study allowed us to calculate the active section of the left earthfill dike of the Belci dam, as well as the volume of material removed by the flood of 1991.

Numerical Simulation of Two-Dimensional Dam Failure and Free-Side Deformation Flow Studies

A dam breaking is a major flood catastrophe. The shape, depth, and wave Doppler effect of initial water flow are all modified as a result of the interaction of the water body with downstream structures after a dam breach, forming a diffraction and reflection flow field. This study investigates the dam breaking problem of a single liquid, by creating a two-dimensional simplified numerical model using the VOF approach, analysing the interaction and effect between barriers of various forms and the dam failure flow, and explains the problem of a complex flow mechanism involving significant deformation of the free surface of a medium. According to the findings, obstacles of varying forms could obstruct the dam break’s water flow to various degrees, and the viscous dissipation characteristic of the water body at the edge of the obstacle is closely related to the slope of the site. The numerical simulation presented in this study is validated, demonstrating its accuracy for both the gate-pulling and downstream wet-bed scenarios.