Reconstruction of the sudden drainage of a moraine-dammed lake in the Cordillera Vilcabamba (Peru): the 2020 Salkantay event

2021 ◽  
Author(s):  
Oscar Vilca ◽  
Martin Mergili ◽  
Adam Emmer ◽  
Holger Frey ◽  
Christian Huggel
Keyword(s):  
Meteorological Data ◽  
High Mountain ◽  
Process Chain ◽  
Remotely Sensed Data ◽  
Two Phase ◽  
Lake Volume ◽  
Landslide Volume ◽  
Before And After ◽  
Displacement Wave ◽  
Dammed Lake

<p>On 23<sup>rd</sup> February 2020, a landslide-triggered GLOF process chain was initiated from the SW slope of Nevado Salkantay, Cordillera Vilcabamba, Peru. An initial slide evolved into a rock/ice avalanche and part of the released material fell into the moraine-dammed Lake Salkantaycocha, triggering a displacement wave which overtopped and eroded the distal face of the dam. Dam overtopping resulted in a far-reaching GLOF causing fatalities and people missing in the valley downstream. In this contribution, we analyse the situation before and after the event as well as the dynamics of the GLOF process chain, based on field investigations, remotely sensed data, meteorological data, and a computer simulation with a two-phase flow model. Comparing pre- and post-event field photographs helped us to estimate the initial landslide volume of 1–2 million m³. Meteorological data suggest rainfall and/or melting/thawing processes as possible causes of the landslide. The simulation reveals that the landslide into the lake created a displacement wave height of up to 27 m. We reconstructed a released volume 57,000 m<sup>3</sup> (less than 10% of lake volume) and estimated a total GLOF peak discharge almost 10,000 m³/s at the dam. The lake had 40 m dam freeboard at the time of a GLOF, and the lake level increased by 10–15 m directly after the event, since most of the volume of landslide material deposited in the lake (roughly 1.3 million m³). The model results show a good fit with the observations, including the travel time to the uppermost village. The findings of this study serve as a contribution to the understanding of landslide-triggered GLOFs in changing high-mountain regions.</p>

scholarly journals Discharge and Sediment Transport in a River Basin. Assessment Before and After the Construction of a Dam at the Upper Basin Boundary

2021 ◽  
Author(s):  
George Paschalidis ◽  
Ilias IIordanidis ◽  
Petros Anagnostopoulos
Keyword(s):  
Sediment Transport ◽  
Meteorological Data ◽  
Climatic Data ◽  
Northern Greece ◽  
Basin Boundary ◽  
Software Packages ◽  
Before And After ◽  
The Mean ◽  
Gis Interface ◽  
Good Agreement

Abstract The purpose of this study is the evaluation of runoff and sediment transport in the basin of the Nestos River (Northern Greece) downstream of the dam of Platanovrisi, constructed in 1998. The model used for the simulation was AGNPS, which is based on the Revised Universal Soil Loss Equation (RUSLE), combined with a GIS interface. Two different simulations were conducted, one for the years 1980-1990 and another for the period 2006-2030, before and after the construction of the dam respectively. For the simulation for the period 1980-1990 existing meteorological data were employed, and the results were in good agreement with those of a different study (Hrissanthou, 2002). The simulation for the period 2006-2030 was based on rainfall and climatic data generated from the software packages GlimClim and ClimGen. The mean runoff was by 5% lower and the mean annual sediment yield by 20% lower than the corresponding values for the period 1980-1990.

scholarly journals Numerical study on the boiling heat transfer induced by two heated plates

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 257-265
Author(s):  
Xiaopeng Shan ◽  
Geng Guan ◽  
Deming Nie
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Numerical Study ◽  
Present System ◽  
Two Phase ◽  
Before And After ◽  
Flow Features ◽  
Boltzmann Method ◽  
Departure Behavior ◽  
Heated Plates

A two-phase lattice Boltzmann method was used to numerically study the boiling heat transfer related to the liquid-vapor transition induced by two heated plates. The effects of the gravity force as well as the separation between the heated plates were examined. The focus is on the bubble departure behavior resulting from the interaction between bubbles, which can be roughly classified into four types of pat?tern according to the separation between plates. In particular, it is shown that the bubble merging may take place twice in one cycle when the separation is close to a certain value. This is referred to as the pattern of alternation of bubble merging before and after departure, for which a sudden jump is seen in the bubble release period. Furthermore, the heat flux and the flow features are also shown to illustrate the behavior of heat transfer in the present system.

scholarly journals PENGURANGAN INTENSITAS FLUKTUASI TEKANAN PADA PEMBESARAN MENDADAK ALIRAN UDARA – AIR SEARAH HORISONTAL DENGAN PENEMPATAN RING

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Mustakim Mustakim ◽  
Indarto Indarto ◽  
Purnomo Purnomo
Keyword(s):  
Water Discharge ◽  
Pressure Fluctuations ◽  
Plug Flow ◽  
Sudden Expansion ◽  
Two Phase ◽  
Differential Pressure Transducer ◽  
Digital Storage ◽  
Before And After ◽  
Voltage Signal ◽  
Fluctuations Intensity

This research aims to reduce the effect of pressure fluctuations intensity on the sudden expansion of two phase flow of air - water in the same direction with the horizontal placement of the ring. Measurements done by installing a differential pressure transducer device that is placed on pressure points before and after sudden expansion. Output voltage signal recorded by a digital storage osciloscope. Tests conducted on water discharge 0.000038 m 3 / s; 0.000078 m 3 / s; 0.000116 m 3 / s; 0.000154 m 3 / s; 0.000198 m 3 / s; 0.000244 m 3 / s; 0.000284 m 3 / s and air flow 0.000065 m 3 / s; 0.00013 m 3 / s; 0.000195 m 3 / s; 0.000255 m 3 / s; 0.00032 m 3 / s; 0.000385 m 3 / s; 0.00045 m 3 / s. Results showed that if the total mass flow rate increases the pressure drop increases. Installation of the ring can reduce the pressure fluctuations intensity, the most effective installation of the ring using the ring the same diameter. Flow path is generally slug and plug flow pattern.

Home care packages: insights into the experiences of older people leading up to the introduction of consumer directed care in Australia

2017 ◽  
Vol 23 (2) ◽  
pp. 162 ◽  
Author(s):  
Jenny Day ◽  
Ann Clare Thorington Taylor ◽  
Peter Summons ◽  
Pamela Van Der Riet ◽  
Sharyn Hunter ◽  
...  
Keyword(s):  
Home Care ◽  
Older People ◽  
Study Data ◽  
Care Quality ◽  
Two Phase ◽  
Face To Face ◽  
Before And After ◽  
Qualitative Descriptive ◽  
Care Coordinators ◽  
Field Notes

This paper reports phase one, conducted from March to June 2015, of a two-phase, qualitative descriptive study designed to explore the perceptions and experiences of older people before and after the introduction of consumer directed care (CDC) to home care packages (HCP) in Australia. Eligible consumers with a local HCP provider were mailed information about the study. Data collection occurred before the introduction of CDC and included face-to-face, in-depth interviews, summaries of interviews, field notes and reflective journaling. Semi-structured questions and ‘emotional touchpoints’ relating to home care were used to guide the interview conversation. Line-by-line data analysis, where significant statements were highlighted and clustered to reveal emergent themes, was used. Five older people, aged 81 to 91 years, participated in the study. The four emergent themes were: seeking quality and reciprocity in carer relationships; patchworking services; the waiting game; and technology with utility. Continuity of carers was central to the development of a trusting relationship and perceptions of care quality among older consumers. Care coordinators and workers should play a key role in ensuring older people receive timely information about CDC and their rights and responsibilities. Participants’ use of contemporary technologies suggests opportunities to improve engagement of HCP clients in CDC.

Life before and after implementation of an acoustic noise reduction enclosure

2005 ◽  
Vol 109 (1092) ◽  
pp. 65-74
Author(s):  
B. Timmins
Keyword(s):  
Wind Tunnel ◽  
Noise Reduction ◽  
Acoustic Noise ◽  
Financial Health ◽  
Two Phase ◽  
North West ◽  
The North ◽  
Close Proximity ◽  
Before And After ◽  
Increase Productivity

Abstract This paper looks back on the designs and ambitions of ARA in resolving a long term acoustic noise problem which threatened ARA with closure. This paper today briefly looks back to the original issues but deals more fully with the later phases of a two phase project implementation and construction. ARA is now a truly ‘silent site’, where closure was once threatened, ARA has achieved the implementation of a bespoke noise reduction enclosure where 24-hour running has proved to be a reality. This paper looks at the design and construction phases, the ‘before and after’ noise footprints and at some of the financial benefits ARA has achieved. The ARA transonic wind tunnel is sited on an industrial estate on the north west perimeter of Bedford. When it was first built it was on an original farm site with no appreciable residential houses in close proximity. Since the early 1950s there has been considerable residential development around the ARA site resulting in the local householders complaining about the wind tunnel acoustic noise. In early 1999 ARA was obliged to consider several options for noise reduction measures to reduce the noise to within UK government statutory requirements. This paper deals briefly with the original noise nuisance characteristics and footprint, the noise reduction design and method that ARA selected and shows the construction phases, the further noise treatment ARA had to do on other major ancillary equipment to make ARA a truly quiet industrial site. The paper shows how ARA has utilised the resulting benefits of these investments to increase productivity and reduce costs, and the influence it has had on ARA’s financial health.

scholarly journals The Study of Sand-blocking Characteristic and Flow Field Simulation Analysis of the Ring-shaped Sand-barrier

2018 ◽  
Vol 38 ◽  
pp. 01044
Author(s):  
Wei Qiang Zheng ◽  
Wen Jun Wei ◽  
Ping Yi Liu
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Simulation Analysis ◽  
Inertia Force ◽  
Two Phase ◽  
Wind Speeds ◽  
Sand Control ◽  
Before And After ◽  
Sand Flow ◽  
Laminar Flow Model

Aiming at the complexity of wind direction and irregular sand flow in a desert area, a combinatorial ring-shaped sand barrier is used. Stokes law of inertia force and centrifugal force and gravity sedimentation are used. With CFD fluid software Fluent, laminar flow model Equation and κ-ε turbulence model, the wind speed of the sand in the sand-gas-solid two-phase flow passing through the circular sand barrier is studied at different distances and different altitudes after the sand barrier, the wind speeds before and after the sand barrier are compared and analyzed . The mean minimum wind speed behind the single sand barrier was reduced by 32.5% -49.4% compared with that before the sand barrier. The wind speed at different height of the composite sand barrier was reduced by 30% -58.3% compared with the inlet wind speed, which solved the problem of irregular wind and sand control in the desert wind direction.

Coherent Expanded Aerogels

1932 ◽  
Vol 5 (4) ◽  
pp. 600-603 ◽  
Author(s):  
S. S. Kistler
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Strong Support ◽  
Liquid Structure ◽  
Extensive Investigation ◽  
Colloid Chemistry ◽  
Similar Form ◽  
Two Phase ◽  
Before And After ◽  
Solid Liquid

Abstract There are few topics in colloid chemistry that have experienced such extensive investigation as that of the structure of gels. Numerous hypotheses have been presented and supported by experimental data of one character or another. Certain aspects of gels have seemed to classify them as solid solutions, others as emulsions, while yet others give strong support to a two-phase, solid-liquid structure. Although the latter theory in similar form to that postulated by Nägeli in 1858 has been accepted by most of the foremost colloid chemists, the evidence has not been sufficiently unequivocal to convince all. The evidence presented in the results of diffusion experiments through gels, the fact that the electrical conductivity, refractive index, and vapor pressure before and after setting are identical, at least in certain cases, and the known facts of syneresis would seem to leave little room for doubt of the two-phase nature of gels in general. A theory in order to be perfectly acceptable must, however, enable verifiable predictions to be made from it.

scholarly journals Investigating Land Surface Temperature Changes Using Landsat Data in Konya, Turkey

2016 ◽  
Vol XLI-B8 ◽  
pp. 285-289 ◽  
Author(s):  
O. Orhan ◽  
M. Yakar
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Salt Lake ◽  
Meteorological Data ◽  
Landsat 8 ◽  
Remotely Sensed Data ◽  
Landsat 5 Tm

The main purpose of this paper is to investigate multi-temporal land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI) changes of Konya in Turkey using remotely sensed data. Konya is located in the semi-arid central Anatolian region of Turkey and hosts many important wetland sites including Salt Lake. Six images taken by Landsat-5 TM and Landsat 8- OLI satellites were used as the basic data source. These raw images were taken in 1984, 2011 and 2014 intended as long-term and short-term. Firstly, those raw images was corrected radiometric and geometrically within the scope of project. Three mosaic images were obtained by using the full-frame images of Landsat-5 TM / 8- OLI which had been already transformed comparison each other. Then, Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI) maps have been produced to determine the dimension of the drought. The obtained results showed that surface temperature rates in the basin increased about 5°C between 1984 and 2014 as long periods, increased about 2-3°C between 2011and 2014 as short periods. Meteorological data supports the increase in temperature.

scholarly journals Detection of earthflow dynamics using medium-resolution digital terrain models: Diachronic perspective of the Jovac earthflow, Southern Serbia

2021 ◽  
Vol 61 (2) ◽  
pp. 187-206
Author(s):  
Marko Milošević ◽  
Dragoljub Štrbac ◽  
Jelena Ćalić ◽  
Milan Radovanović
Keyword(s):  
Digital Terrain Models ◽  
Digital Terrain ◽  
Terrain Models ◽  
Landslide Volume ◽  
Medium Resolution ◽  
Before And After ◽  
Movement Mechanism ◽  
Research Procedure ◽  
Definition Of

The paper presents and discusses the landslide research procedure related to the topography before and after its occurrence, using the comparative analysis of two medium-resolution digital terrain models. The case study is the Jovac mega-landslide—the largest landslide to occur in Serbia in the last 100 years, active for three days in February 1977. The indicators used to determine the volume and movement mechanism were the spatial distribution of elevation differences within the two digital terrain models (DTM), and the analysis of geomorphological features before the landslide. The obtained elevation differences allowed the definition of the approximate landslide volume: 11.6 × 106 m3. All the data obtained indicate that the movement mechanism falls into the category of earthflow.

scholarly journals Controls on the formation and size of potential landslide dams and dammed lakes in the Austrian Alps

2021 ◽  
Vol 21 (5) ◽  
pp. 1615-1637
Author(s):  
Anne-Laure Argentin ◽  
Jörg Robl ◽  
Günther Prasicek ◽  
Stefan Hergarten ◽  
Daniel Hölbling ◽  
...  
Keyword(s):  
Real World ◽  
Fluid Dynamic ◽  
Probabilistic Approach ◽  
Drainage System ◽  
Austrian Alps ◽  
Lake Volume ◽  
Landslide Dams ◽  
Landslide Volume ◽  
Lake Formation ◽  
Lake Size

Abstract. Controls on landsliding have long been studied, but the potential for landslide-induced dam and lake formation has received less attention. Here, we model possible landslides and the formation of landslide dams and lakes in the Austrian Alps. We combine a slope criterion with a probabilistic approach to determine landslide release areas and volumes. We then simulate the progression and deposition of the landslides with a fluid dynamic model. We characterize the resulting landslide deposits with commonly used metrics, investigate their relation to glacial land-forming and tectonic units, and discuss the roles of the drainage system and valley shape. We discover that modeled landslide dams and lakes cover a wide volume range. In line with real-world inventories, we further found that lake volume increases linearly with landslide volume in the case of efficient damming – when an exceptionally large lake is dammed by a relatively small landslide deposit. The distribution and size of potential landslide dams and lakes depends strongly on local topographic relief. For a given landslide volume, lake size depends on drainage area and valley geometry. The largest lakes form in glacial troughs, while the most efficient damming occurs where landslides block a gorge downstream of a wide valley, a situation preferentially encountered at the transition between two different tectonic units. Our results also contain inefficient damming events, a damming type that exhibits different scaling of landslide and lake metrics than efficient damming and is hardly reported in inventories. We assume that such events also occur in the real world and emphasize that their documentation is needed to better understand the effects of landsliding on the drainage system.

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