Dam Burst Research Articles

A modelling approach to assess the impact of land mining on marine biodiversity: Assessment in coastal catchments experiencing catastrophic events (SW Brazil)

Analysis that link hydrological processes with oceanographic dispersion offer a promising approach for assessing impacts of land-based activities on marine ecosystems. However, such an analysis has not yet been customised to quantify specific pressures from mining activities on marine biodiversity including those from spillages resulting from tailing dam failure. Here, using a Brazilian catchment in which a tailing dam collapsed (Doce river) as a case study, we provide a modelling approach to assess the impacts on key ecosystems and marine protected areas subjected to two exposure regimes: (i) a pulse disturbance event for the period 2015–2016, following the immediate release of sediments after dam burst, which witnessed an average increase of 88% in sediment exports; and (ii) a press disturbance phase for the period 2017–2029, when impacts are sustained over time by sediments along the river's course. We integrated four components into impact assessments: hydrological modelling, coastal-circulation modelling, ecosystem mapping, and biological sensitivities. The results showed that pulse disturbance causes sharp increases in the amount of sediments entering the coastal area, exposing key sensitive ecosystems to pollution (e.g. rhodolith beds), highlighting an urgent need for developing restoration strategies for these areas. The intensity of impacts will diminish over time but the total area of sensitive ecosystems at risk are predicted to be enlarged. We determined monitoring and restoration priorities by evaluating and comparing the extent to which sensitive ecosystems within marine protected areas were exposed to disturbances. The information obtained in this study will allow the optimization of recovery efforts in the marine area affected, and valuation of ecosystem services lost.

Ecology and mining industry development in high-mountain areas (the Inner Tien Shan)

The genesis and transformation in time of risks in the areas of high altitude tailings storage facilities with respect to changing climate are considered. Based on the example of the Kumtor mine in the center of the Tien Shan at a height of 3600-4300 m, three groups of risk factors were allocated concerning a large, ecologically hazardous facility - the tailings dam containing cyanide waste. For one of the factors, calculations of an accidental dam burst were made using the Fault Tree Analysis (FTA) method. It was concluded that the construction of large-scaled and geoenvironmentally hazardous facilities in less researched high-mountain areas has to be be drawn upon detailed and permanent monitoring of the facility itself and its environment. It is crucial to be prepared for operational adjustment of projects and an immediate rehabilitation of constructed facilities.

Potential risks of the residue from Samarco's mine dam burst (Bento Rodrigues, Brazil)

On November 5th, 2015, Samarco's iron mine dam – called Fundão – spilled 50–60 million m3 of mud into Gualaxo do Norte, a river that belongs to Rio Doce Basin. Approximately 15 km2 were flooded along the rivers Gualaxo do Norte, Carmo and Doce, reaching the Atlantic Ocean on November 22nd, 2015. Six days after, our group collected mud, soil and water samples in Bento Rodrigues (Minas Gerais, Brazil), which was the first impacted area. Overall, the results, water samples – potable and surface water from river – presented chemical elements concentration according to Brazilian environmental legislations, except silver concentration in surface water that ranged from 1.5 to 1087 μg L−1. In addition, water mud-containing presented Fe and Mn concentrations approximately 4-fold higher than the maximum limit for water bodies quality assessment, according to Brazilian laws. Mud particle size ranged from 1 to 200 μm. SEM-EDS spot provided us some semi quantitative data. Leaching/extraction tests suggested that Ba, Pb, As, Sr, Fe, Mn and Al have high potential mobilization from mud to water. Low microbial diversity in mud samples compared to background soil samples. Toxicological bioassays (HepG2 and Allium cepa) indicated potential risks of cytotoxicity and DNA damage in mud and soil samples used in both assays. The present study provides preliminary information aiming to collaborate to the development of future works for monitoring and risk assessment.

Fate and Environmental Impact of Thorium Residues During Rare Earth Processing

Rare earth (RE) processing is an environmental hazardous operation. Processed minerals often contain radioactive elements like thorium which occur together with the precious RE elements due to their chemical and physical similarities. Environmental contamination with thorium around RE mining and processing sites is an issue of concern, and many incidences of health impact have been reported. Thorium is enriched during different processing steps like flotation or leaching activities. Therefore, thorium-containing waste arising during RE processing needs a careful waste management since contamination, e.g. by dust drift or tailing dam bursts are severe threats for exposed organisms in the environment. The aim of the paper is to summarize the routes of thorium enrichment along RE mining processes along with the environmental impact and to provide suggestions how to manage thorium enriched waste.

English

English

Sedimentary characteristics of palaeolake deposits along the Indus River valley, Ladakh, Trans‐Himalaya: Implications for the depositional environment

ABSTRACTThis study is an attempt to contribute to the data set of granulometric studies of sediments by measuring the sedimentary structure and texture, along with statistical parameters, of cold and arid lake systems. The palaeolake sequence along the River Indus on the western fringe of the Tibetan Plateau in Ladakh sector was selected in order to shed light on depositional environmental changes within the lake from post‐last glacial maximum to 5 ka. The River Indus was blocked by Lamayuru dam burst during the deglaciation, after the Last Glacial Maximum (LGM) and the subsequent increase in water level led to the formation of the Saspol–Khalsi palaeolake. This lake was ca 55 km in length, extending from Nimo to Khalsi, had a surface area of 370 km2 and was in existence until 5 ka. Two sections (Saspol and Khalsi) separated by an aerial distance of 35 km show a similar trend in sediment character due to their deposition in the same lake system. Grain‐size studies show a polymodal nature of sediments for both of the sections. However, sediments of the lower/downstream section (Khalsi) show a poorer degree of sorting, and coarser grain size and high energy depositional condition as compared with the sediments of Saspol section (positioned upstream) due to the location of the sections within the lake system. It was noted that, in high‐altitude arid regions, the sedimentological characteristics of large‐sized valley lakes may vary greatly, horizontally as well as vertically, owing to local stream input, inflow intensity from the catchment, outflow velocity of water channels, lithology and valley widths at the different sites.

The Dam Bursts for Porous Liquids.

In 2007 the idea was put forward that, through careful molecular design, it should be possible to synthesize liquids which contain permanent, well-defined molecule-sized cavities (pores). Such "porous liquids" could be a kind of liquid zeolite, or liquid MOF (metal-organic framework), exhibiting the size and shape-selective sorption (or dissolution) associated with microporous solids as well as the fluidity of liquids - a new and potentially useful combination of properties. However, these materials remained essentially hypothetical until recently. In 2014 and 2015 three papers were published which describe convincing examples of porous liquids, and studies have shown that they do exhibit some remarkable properties, such as very fast gas diffusion and high gas solubilities. The examples reported so far are almost certainly only the tip of the iceberg. Now that porous liquids are 'real', a new area of materials science may open up, with clear potential for long-term applications in chemical processes.

The Impending Dam Disaster in the Himalayan Mountains.

The article discusses the risk of earthquake-related dam bursts in the Himalayan Mountains. According to the author, Chinese and Indian dams in geologically active areas could cause significant damage if they experience failure during predicted earthquakes. It is suggested that both China and India have withheld information about the design and robustness of their dams. Other topics include corruption and the Tehri Dam in the Central Himalayas.

Analysis of 30 years rainfall variability in Imo State of southeastern Nigeria

Many variations in rainfall have occurred for different climatic regions and individual locations in Nigeria with associated disasters. Every rainy season in Nigeria, wind gusts arising from tropical storms claim lives and properties worth millions of naira across the country. Flash floods from torrential rains wash away thousands of hectares of farmland. Dam bursts are common following such floods. Rainfall is one of the atmospheric driving forces responsible for climate variation and its effects in Imo state of Nigeria as in other parts of the world. A study in 2009 indicated that about 16% of the erosion in Owerri Municipality of Imo State is caused by rainfall (Maduka, 2009). Other current research shows that 91% of malaria cases in Orlu, Imo State, are attributed to rainfall variability (Okorie et al. 2014), which means that rainfall promotes mosquito breeding. The aim of this research is to analyse variability in rainfall in Imo State of Nigeria over 30 years. Ground truth precipitation data for 1980−2009 acquired from Nigeria Meteorological Department were used. The results show many variations in rainfall within the period under study, which have caused some environ-hydrological problems including coastal erosion, flooding and flood-related disasters (such as pollution, increased disease vectors, communicable diseases and epidemics). Such hydrological problems are the effects of climate variation induced by rainfall anomalies. Imo State is located between latitude 4°45′N and 7°15′N and longitude 6°50′E and 7°25′E, with an area of about 5100 km 2 . It lies within the humid tropics and is generally characterized by a high surface air temperature regime year-round. Mean minimum temperature is 23.5°C and mean maximum temperature is 32.1°C. Two seasons, wet and dry, are observed in the year. The rainy seasons begin in April and lasts till October. The State experiences climate variations following rainfall variability. It is on this premise therefore, that this study focused on determination of the shifts in rainfall and the associated disasters as the evidence of climate variation in Imo State. METHODOLOGY Mean monthly rainfall data from Owerri synoptic station between 1980 and 2009 converted to annual mean were collected from the Nigerian Meteorological Department, Lagos (Table 1). Rainfall data is used in this study as an indication of rainfall being a key climatic variable. The research covers one climatic period of 30 years that provides a better platform to investigate the variability and changes in the climate systems in the study area. The mean annual rainfall data were used to construct a rainfall chart of the state for the climatic period (Fig. 1) and with the chart, the analysis of the pattern and trends of rainfall in the area was carried out. RESULTS AND DISCUSSION

Debris flows and their toll on human life: a global analysis of debris-flow fatalities from 1950 to 2011

Debris flows cause significant damage and fatalities throughout the world. This study addresses the overall impacts of debris flows on a global scale from 1950 to 2011. Two hundred and thirteen events with 77,779 fatalities have been recorded from academic publications, newspapers, and personal correspondence. Spatial, temporal, and physical characteristics have been documented and evaluated. In addition, multiple socioeconomic indicators have been reviewed and statistically analyzed to evaluate whether vulnerable populations are disproportionately affected by debris flows. This research provides evidence that higher levels of fatalities tend to occur in developing countries, characterized by significant poverty, more corrupt governments, and weaker healthcare systems. The median number of fatalities per recorded deadly debris flow in developing countries is 23, while in advanced countries, this value is only 6 fatalities per flow. The analysis also indicates that the most common trigger for fatal events is extreme precipitation, particularly in the form of large seasonal storms such as cyclones and monsoon storms. Rainfall caused or triggered 143 of the 213 fatal debris flows within the database. However, it is the more uncommon and catastrophic triggers, such as earthquakes and landslide dam bursts, that tend to create debris flows with the highest number of fatalities. These events have a median fatality count >500, while rainfall-induced debris flows have a median fatality rate of only 9 per event.

Dam Burst of Emotion

WHO estimates that every year around 15 million babies are born preterm. Of these, around 1 million babies die due to complications of preterm birth. Survival is dependent on the quality of health care available to these babies. It is estimated that more than 3/4th of babies can be salvaged by timely and appropriate care. The author considered herself to be one of the privileged members of society, being a doctor themselves, living in a metropolitan society and having access to the best healthcare in the country. However, this overconfidence was rudely shaken when they ran from one hospital to another in search of a ventilator for their as yet unborn baby. The author's pregnancy and child birth brought them closer to the millions of parents who undergo the trauma of having a premature baby.

A 1000-year history of large floods in the Upper Ganga catchment, central Himalaya, India

Determining the frequency, magnitude and causes of large floods over long periods in the flood-prone Himalaya is important for estimating the likelihood of future floods. A thousand year record (with some information from 2600 years ago) of the frequency and some estimates of velocities and discharges of large floods has been reconstructed in the Upper Ganga catchment, India, using written reports, litho-stratigraphy and sedimentology, and dated by optical and radiocarbon methods. In the Upper Ganga catchment rainfall triggers large landslides that dam rivers and release large amounts of water when they burst, thereby amplifying the effects of rainfall. The large floods in the catchment may be the result of landslide dam bursts rather than glacial lake bursts, and these are likely to continue and possibly worsen as the monsoon intensifies over the next century. However preliminary information suggests that the recent devastating flood of June 2013 was the result of heavy rainfall not landslide dam bursts. The frequency record is non-random and shows a high frequency between AD 1000 and AD 1300 (omitting uncertainties), then a low frequency until a cluster of floods occurred about 200 years ago, then increased frequency. This temporal pattern is like but not identical with that in Peninsular India, and both appear to be the result of variations in the monsoon.

Formation, failure, and consequences of the Xiaolin landslide dam, triggered by extreme rainfall from Typhoon Morakot, Taiwan

An extreme rainfall event on August 9, 2009, which was close to setting a world record for 48-h accumulated rainfall, induced the Xiaolin deep-seated landslide, which was located in southwestern Taiwan and had volume of 27.6 × 106 m3, and caused the formation of a landslide dam. The landslide dam burst in a very short time, and little information remained afterward. We reconstructed the process of formation and failure of the Xiaolin landslide dam and also inferred the area of the impoundment and topographic changes. A 5 × 5-m digital elevation model, the recorded water stage of the Qishan River, and data from field investigation were used for analysis. The spectral magnitude of the seismic signals induced by the Xiaolin landslide and flooding due to failure of the landslide dam were analyzed to estimate the timing of the dam breach and the peak discharge of the subsequent flood. The Xiaolin landslide dam failure resulted from overtopping. We verified the longevity of the Xiaolin landslide dam at about 2 h relying on seismic signals and water level records. In addition, the inundated area, volume of the impoundment behind the Xiaolin landslide dam, and peak discharge of the flood were estimated at 92.3 ha, 19.5 × 106 m3, and 17 × 103 m3/s, respectively. The mean velocity of the flood-recession wave front due to the dam blockage was estimated at 28 km/h, and the peak flooding velocity after failure of the dam was estimated at 23 km/h. The Xiaolin landslide provides an invaluable opportunity for understanding the mechanism of deep-seated landslides and flooding processes following a landslide dam failure.

MEMS-Integrated Load Cell for Measuring Pressure, Erosion, and Deposition in Dynamic Environmental Flows

A microelectromechanical system-based load cell is integrated with signal conditioning circuitry, temperature, and tilt sensors for measurement of sediment-fluid interaction and flow under turbulent conditions. Such an instrument has potential value for quantifying geophysical flows and sediment dynamics within a range of environments. Sensor sensitivity is tested to a mass of 0.5 g but can be shown theoretically to extend to 50 mg. The sensor is found to have no attenuation of frequencies up to 2.5 Hz and would therefore be suitable for monitoring turbulent flow. Laboratory flume experiments, simulating a dam burst, demonstrate the applicability of the sensor for measuring highly dynamic and transient flow phenomena in unprecedented detail.

Debris Flow Warning System Design by Diao Zhongba on the Basis of GIS

Aiming at guaranteeing the security of Zhong Ba village, reducing investment capital and preventing geological disasters, it is necessary to design debris flow alarming system in Diao Zhongba. Being a basic platform, geographic information system software MAPGIS is fully taken advantage for managing engineering geology information in Diao Zhongba. Then research on secondary development library based on MAPGIS is conducted for achieving debris flow alarming function. Detailed design of debris flow alarming system in Diao Zhongba district is made on systematic requirement analyses, systematic overall design, system environment selection, data base detailed design and module design on alarming function. The system designs 10 kinds of models in all which includes flood peak flow computation model of dam breaking and flood peak evolution process model of dam burst. The system can conduct an automate information process on debris flow with which serves as the references for debris flow alarming in Diao Zhongba district.

Interruptions of the ancient Shu Civilization: triggered by climate change or natural disaster?

Environmental proxies of a stable carbon isotope, total organic carbon, free iron oxide, and particle size distribution in sediments as well as the stable carbon and oxygen isotopes in fossil human and animal teeth were used to reconstruct the history of climate change and natural disasters near the Jinsha Relic Site and to track their effect on the ancient Shu Civilization, which was established in the Chengdu Plain of southwest China during the late Holocene. In general, the late Holocene climate in the Chengdu Plain demonstrated a drying and cooling trend, with evident cooler events ~4100 and ~2700 a BP, which coincided with global climate changes. The ancient Shu Civilization was interrupted twice, and it included three stages—the Baodun (4700–3700 a BP), the Sanxingdui (3700–3150 a BP), and the Shi’erqiao (3150–2600 a BP)—that were slightly related to the abrupt climate changes that resulted from the collapse of the classic Sanxingdui Civilization, which was founded in a regional warm period. The abrupt increase in sand content in the sediment from the Jinsha Site coincided with the palaeoearthquake and palaeodam burst in the Longmen Mountains when the Baodun and Shi’erqiao desisted, indicating that a flood had occurred due to a dam burst and may likely have caused the ancient civilization’s destruction. Although the warm and humid climate, flat terrain and rich water resources prompted the prosperity of the ancient towns of Sanxingdui and Jinsha, frequent natural disasters, such as powerful earthquakes, landslide dams, and outburst floods, consistently affected the ancient Shu inhabitants.

Landslide dam and subsequent dam-break flood estimation using HEC-RAS model in Northern Pakistan

On the morning of January 4, 2010, a massive landslide swept the Attabad and Sarat villages into the Hunza River. The debris from the landslide blocked the low-lying river, creating a barrier lake in the area and poses a major threat to the villages located downstream. The aim of the current study was to evaluate the environmental advantages and disadvantages created by the formation of the artificial lake. For this purpose, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were used to create the contours and triangulated irregular network (TIN) of the region. Data from ‘Google Earth’ image on March 19, 2010 were used as the reference and to determine the river bed elevation of the study area. Landsat satellite data of Enhanced Thematic Mapper Plus (ETM+) sensor on January 10, March 15, April 24 and May 2, 2010, were used for constructing the Geographic Information System (GIS) layers of the river banks, land use area, overbank flow area and water area estimation. Our results show that the area covered by the water in the lake has increased from 1.28 km2 on January 10, 2010 to 6.25 km2 on May 2, 2010. The total upstream urban area affected by the river blockage is 13.99 km2. We also applied the Hydrologic Engineering Center River Analysis System (HEC-RAS) model to estimate the potential catastrophes due to dam burst for different peak outflow scenarios with conclusions and recommendations.

A Mathematical Model for Forecasting the Dam‐Break Flood Routing Process of a Landslide Dam

Once a landslide dam bursts, its reservoir discharges quickly in a flood which will cause catastrophic damage to life and property downstream. For a specific landslide dam, the peak flow rate and the evolution of downstream flood are influenced by the shape and size of the dike breach when dam‐break occurs. According to the general nature of landslide dams and field observations of dike‐breach development patterns, a dike‐breach propagation mode has been determined. By combining an improved empirical equation with knowledge of the dike‐breach propagation mode, a mathematical model for forecasting dam‐break flood routing has been developed and is presented here. Sensitivity analysis was then carried out based on the computed results for peak flow rate and the flood evolution curve under different parameters. The computed results showed that the width coefficient and the depth coefficient had similar effects on the dam‐break flood but that the impact of the depth coefficient was more significant than that of the width coefficient. Finally, the proposed model was used to calculate the flood evolution for the Tangjiashan landslide dam. The computed results showed that the error between the simulated result and the measured data was less than 5%.

Prediction of Floods Caused by Landslide Dam Collapse

Landslide dam formation and deformation strongly affect water and sediment runoff. When a large-scale landslide dam collapses due to overflow erosion, peak flood discharge may exceed inflow discharge by several times. Such an abrupt flow discharge increase by a dam burst may cause serious damage downstream. We propose a one-dimensional model for river-bed variation and flood runoff consisting of a two-layer model for immature debris flow and a bank erosion model. We applied this model to the Nonoo landslide dam in Japan’s Miyazaki Prefecture, formed by typhoon Nabi in September 2005, and China’s Tangjiashan landslide dam formed in the Wenchuan earthquake in May 2008. The model reproduces the observed flood runoff processes in the two areas. Calculated results suggest that peak flood discharge diminishes when water accumulating behind the landslide dam is small, and excavating the landslide dam crown effectively reduces flood discharge.

Temporal variation in Sr and 87Sr/86Sr of the Brahmaputra: Implications for annual fluxes and tracking flash floods through chemical and isotope composition

Temporal variations in dissolved Sr and its 87Sr/86Sr in the Brahmaputra River were determined for the first time by analyzing biweekly samples collected over a period of about a year at Guwahati. Sr in the Brahmaputra range from 0.604 to 1.392 μM with 87Sr/86Sr of 0.71594 to 0.71802. Sr concentration decreases in monsoon (except for the 15 June 2000 sample, which had anomalously high concentrations of Sr and major ions) compared to the nonmonsoon period. The decrease in elemental abundances, a factor of ∼2, is not proportional to the increase in discharge, an order of magnitude, indicating enhanced weathering during monsoon. This can be a cumulative effect of an increase in drainage area and in physical weathering during monsoon. 87Sr/86Sr and other proxies of silicate weathering show a relatively lower contribution from silicate weathering to the major ion and Sr budget during monsoon with a concomitant increase in carbonate weathering contribution. Shorter interaction time between water and minerals during monsoon coupled with the slower weathering kinetics of silicate compared to carbonate can be contributing factors to the seasonal changes in their relative contributions to the major ion budget. This study shows that the annual fluxes of various ions, ΣCatsil, and Srsil calculated on the basis of measured biweekly concentrations and monthly water discharge data are roughly within ±35% of those calculated using either the lowest or the highest concentrations and annual water discharge. This implies that a tropical region such as in India, where river discharge is governed mostly by monsoon rains, the annual elemental fluxes measured during monsoon would be a good approximation for their discharge weighted annual fluxes; however, an additional sampling during a drier period would be required to understand the weathering processes. The geochemistry of the 15 June 2000 sample is anomalous. The chemistry of this sample is similar to those from the Tibetan region, an inference consistent with reports of a flash flood in the Brahmaputra due to a natural dam burst in the Yigong River of Tibet. These results highlight the use of the chemical and isotopic composition of water samples to track and quantify the source and discharge of a flash flood.