Modelling the efficiency of a drainage gallery work for a large landslide with respect to hydrogeological heterogeneity

2012 ◽  
Vol 49 (8) ◽  
pp. 968-985 ◽  
Author(s):  
Boris Matti ◽  
Laurent Tacher ◽  
Stephane Commend
Keyword(s):  
Factor Of Safety ◽  
Drainage System ◽  
Significant Gain ◽  
Deep Drainage ◽  
Large Landslide ◽  
The Impact ◽  
Polytechnical School

This study describes transient hydrogeological and geomechanical models realized jointly in 2006 by the Geolep office (Géologie de l’Ecole Polytechnique) of the Polytechnical School of Lausanne (EPFL) and GeoMod SA within the framework of the stabilization work of the La Frasse landslide (Vaud, Switzerland). These models evaluate the impact of a deep drainage gallery with subvertical drainage boreholes towards the surface in terms of reduction of the deformation velocities and increase of the landslide’s factor of safety. The paper presents the effect of different pipe spacing of the drainage system. Considering the local heterogeneities, the results show that a mean spacing between the drainage boreholes of the order of 10 m is sufficient to control the temporal head fluctuations between the wells within a range of a few metres. Moreover, this solution induces a strong diminution of the predicted displacements during a specific crisis, from 101 cm for the model without drainage to around 14 cm for the drained model, and a significant gain of stability (from a factor of safety (FoS) of 1.05 to 1.30).

scholarly journals Advances and Challenging Issues in Subsurface Drainage Module Technology and BIOECODS: A Review

2018 ◽  
Vol 203 ◽  
pp. 07005 ◽  
Author(s):  
Abdurrasheed Sa'id Abdurrasheed ◽  
Khamaruzaman Wan Yusof ◽  
Husna Bt Takaijudin ◽  
Aminuddin Ab. Ghani ◽  
Muhammad Mujahid Muhammad ◽  
...  
Keyword(s):  
Drainage System ◽  
Numerical Data ◽  
Subsurface Drainage ◽  
Infiltration Capacity ◽  
Sustainable Solutions ◽  
Ecologically Sustainable ◽  
The Impact ◽  
Flow Attenuation ◽  
Permeability Rate ◽  
Over Time

Subsurface drainage modules are important components of the Bio-ecological Drainage System (BIOECODS) which is a system designed to manage stormwater quantity and quality using constructed grass swales, subsurface modules, dry and wet ponds. BIOECODS is gradually gaining attention as one of the most ecologically sustainable solutions to the frequent flash floods in Malaysia and the rest of the world with a focus on the impact of the subsurface modules to the effectiveness of the system. Nearly two decades of post-construction research in the BIOECODS technology, there is need to review findings and areas of improvement in the system. Thus, this study highlighted the key advances and challenges in these subsurface drainage modules through an extensive review of related literature. From the study, more work is required on the hydraulic characteristics, flow attenuation and direct validation methods between field, laboratory, and numerical data. Also, there is concern over the loss of efficiency during the design life especially the infiltration capacity of the module, the state of the geotextile and hydronet over time. It is recommended for the sake of higher performance, that there should be an onsite methodology to assess the permeability, rate of clogging and condition of the geotextile as well as the hydronet over time.

scholarly journals Straight to Low-Sinuosity Drainage Systems in a Variscan-Type Orogen—Constraints from Tectonics, Lithology and Climate

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 933
Author(s):  
Harald G. Dill ◽  
Andrei Buzatu ◽  
Sorin-Ionut Balaban
Keyword(s):  
Chemical Weathering ◽  
Current Model ◽  
Drainage System ◽  
Numerical Data ◽  
Structural Features ◽  
Acute Angle ◽  
Drainage Systems ◽  
Starting Point ◽  
Bedrock Lithology ◽  
The Impact

A holistic-modular approach has been taken to study the evolution of three straight to low-sinuosity drainage systems (=SSS) in an uplifted basement block of the Central European Variscides. The development of the SSS is described by means of a quadripartite model. (1) The geological framework of the SSS: Forming the lithological and structural features in the bedrock as a result of different temperature, pressure and dynamic-metamorphic processes. (2) Prestage of SSS: Forming the paleo-landscape with a stable fluvial regime as a starting point for the SSS. (3) Proto-SSS: Transition into the metastable fluvial regime of the SSS. (4) Modern SSS: Operation of the metastable fluvial regime Tectonics plays a dual role. Late Paleozoic fold tectonic creates the basis for the studied SSS and has a guiding effect on the development of morphotectonic units during the Neogene and Quaternary. Late Cenozoic fault tectonics triggered the SSS to incise into the Paleozoic basement. The change in the bedrock lithology has an impact on the fluvial and colluvial sediments as well as their landforms. The latter reflects a conspicuous modification: straight drainage system ⇒ higher sinuosity and paired terraces ⇒ hillwash plains. Climate change has an indirect effect controlling via the bedrock the intensity of mechanical and chemical weathering. The impact on the development of the SSS can be assessed as follows: Tectonics >> climate ≅ bedrock lithology. The three parameters cause a facies zonation: (1) wide-and-shallow valley (Miocene), (2) wide-angle V-shaped valley (Plio-Pleistocene), (3) acute-angle V-shaped valley (Pleistocene), (4) V-shaped to U-shaped valleys (Pleistocene-Holocene). Numerical data relevant for the hydrographic studies of the SSS are determined in each reference area: (1) Quantification of fluvial and colluvial deposits along the drainage system, (2) slope angles, (3) degree of sinuosity as a function of river facies, (4) grain size distribution, (5) grain morphological categorization, (6) grain orientation (“situmetry”), (7) channel density, (8) channel/floodplain ratios. Thermodynamic computations (Eh, pH, concentration of solubles) are made to constrain the paleoclimatic regime during formation of the SSS. The current model of the SSS is restricted in its application to the basement of the Variscan-Type orogens, to an intermediate crustal maturity state.

scholarly journals The impact of agriculture drainage reconstruction on ground water recession close to the subgrade

2015 ◽  
Vol 10 (3) ◽  
pp. 230-238 ◽  
Author(s):  
Vilimantas Vaičiukynas ◽  
Saulius Vaikasas ◽  
Henrikas Sivilevičius ◽  
Audrius Grinys
Keyword(s):  
Agricultural Land ◽  
Drainage System ◽  
Hydraulic Permeability ◽  
Road Maintenance ◽  
Permeability Characteristics ◽  
The Road ◽  
The Impact ◽  
Good Drainage ◽  
Important Design ◽  
Local Road

Good drainage is the most important design consideration for a road, both to miniaturize road maintenance costs and maximize the time the road is operational. The lack of good drainage lead to the structural damages and costly repairs. Many of roads are built in intensively drained agricultural land. The effective way to drain subgrades is reconstruction of existing agricultural drainage. The impact of cross-subsurface drainage system on water level fluctuation was measured using Plane geofiltration mathematical model, one of 3D geofiltration modelling programs. The hydraulic permeability characteristics were determined in field of Pikeliai, close to local road in Kėdainiai district, Lithuania. This object is composed of clay and loamy soils. Subsurface cross drains trenches spacing of 20 m, 30 m and 40 m were simulated. The hydraulic permeability of cross drain trenches and lateral trenches modelled was from 0.006 m/a day to 6 m/a day. The simulation of cross drains trenches showed that the most effective distance between them are 20 m. The highest water depression occurs when the permeability of cross drain trenches and lateral trenches is ~ 6 m/day, at the distance of 20 m. The water recession is 20 cm lower compared to the drainage systems without cross drains trenches. By installing cross drains trenches every 30 m, water recession is 10 cm lower when the trench permeability is about 6 m/day. When increasing the distance between the cross drains up to 40 m their influence disappears.

scholarly journals Corrugated Galvanised Iron Sheet as an Alternative to Conventional Roofing Materials “A case study from Sakteng Wildlife Sanctuary, Bhutan”

2018 ◽  
Vol 6 (01) ◽  
Author(s):  
Sonam Tobgay ◽  
Kumbu Dorji ◽  
Norbu Yangdon
Keyword(s):  
Habitat Management ◽  
Positive Impact ◽  
Natural Habitat ◽  
Drainage System ◽  
Development Program ◽  
Wildlife Sanctuary ◽  
Run Off ◽  
Community Pressure ◽  
The Impact ◽  
Roofing Materials

Corrugated galvanized iron (CGI) sheet as an alternative to conventional roofing material was initiated under the integrated conservation development program (ICDP) of Sakteng Wildlife Sanctuary in the year 2004. The program was aimed at reducing community pressure on natural resources to enhance conservation of biodiversity and keystone fauna and flora species through protection of wild habitat. It has benefited 628 inhabitants of Merak and Sakteng which were identified as the least developed among 15 Gewogs (Blocks) under Trashigang Dzongkhag (District). Data were collected through semi structured questionnaires to study the impact of the program to policy and natural habitat management. Amongst the two types of conventional roofing materials available in the locality, Shingles (79%) were in extensive use in comparison to Bamboo mat (21%) attributing to its durability. However, people prefer to use CGI sheet (100%) roofing which is economical, durable and effective in comparison to Shingle and Bamboo mat roofing, where incidences of water seepage to the room is frequent and requires replacing after 5.6 and 1.7 years respectively incurring higher maintenance costs. Replacing conventional roofing with CGI sheet has a long-term positive impact to conservation of forest and wild habitat. It is estimated that under ideal conditions approximately 5521 healthy matured Fir trees (>4'1''girth) and 1.68 million Bamboos were saved from felling since the initial supply of CGI sheet. However, effective roofing has led to the construction of the illegal permanent concrete huts in the Tsamdro (pastureland) and changes in the architectural designs of their native houses. The need of proper drainage system was also observed as important to reduce the gully erosion from CGI sheet roof run-off.

Vulnerability of coastal areas to increased aquifer saturation due to climate change

2021 ◽  
Author(s):  
Alexandre Gauvain ◽  
Ronan Abhervé ◽  
Jean-Raynald de Dreuzy ◽  
Luc Aquilina ◽  
Frédéric Gresselin
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Large Scale ◽  
Regional Scale ◽  
Drainage System ◽  
Hydrological Regime ◽  
Coastal Areas ◽  
Western Coast ◽  
Study Sites ◽  
The Impact

<p>Like in other relatively flat coastal areas, flooding by aquifer overflow is a recurring problem on the western coast of Normandy (France). Threats are expected to be enhanced by the rise of the sea level and to have critical consequences on the future development and management of the territory. The delineation of the increased saturation areas is a required step to assess the impact of climate change locally. Preliminary models showed that vulnerability does not result only from the sea side but also from the continental side through the modifications of the hydrological regime.</p><p>We investigate the processes controlling these coastal flooding phenomena by using hydrogeological models calibrated at large scale with an innovative method reproducing the hydrographic network. Reference study sites selected for their proven sensitivity to flooding have been used to validate the methodology and determine the influence of the different geomorphological configurations frequently encountered along the coastal line.</p><p>Hydrogeological models show that the rise of the sea level induces an irregular increase in coastal aquifer saturations extending up to several kilometers inland. Back-littoral channels traditionally used as a large-scale drainage system against high tides limits the propagation of aquifer saturation upstream, provided that channels are not dominantly under maritime influence. High seepage fed by increased recharge occurring in climatic extremes may extend the vulnerable areas and further limit the effectiveness of the drainage system. Local configurations are investigated to categorize the influence of the local geological and geomorphological structures and upscale it at the regional scale.</p>

A Novel Drainage System Using Cellular Automata to Avoid Urban Flood

2018 ◽  
Vol 9 (2) ◽  
pp. 38-51
Author(s):  
Neeraj Kumar ◽  
Alka Agrawal ◽  
Raees Ahmad Khan
Keyword(s):  
Cellular Automata ◽  
Smart City ◽  
Water Storage ◽  
Drainage System ◽  
Urban Flood ◽  
Long Duration ◽  
Storage Methods ◽  
The Impact ◽  
Removal System

Floods are problems which become disasters if they persist for a long duration. Out of all kind of floods, a rainfall-induced flood is just a problem created by a lack of water storage methods, which can be eliminated if a better removal system is available. For flood avoidance, many methods have been used, out of which a dedicated drainage pipeline structure may facilitate better removal. This article shows the theory of cellular automata with its new application for flood avoidance using ground leveling. This article analyzes the performance of hexagonal shapes compared with a popular rectangle grid. The article also shows the impact of various layers on the size of the tank. This article provides knowledge towards the flood avoidance for a flood free smart city.

scholarly journals Effects of suspended micro- and nanoscale particles on zooplankton functional diversity of drainage system reservoirs at an open-pit mine

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anna Maria Goździejewska ◽  
Monika Gwoździk ◽  
Sławomir Kulesza ◽  
Mirosław Bramowicz ◽  
Jacek Koszałka
Keyword(s):  
Functional Diversity ◽  
Drainage System ◽  
Open Pit ◽  
Nanoscale Particles ◽  
X Ray ◽  
Force Microscopy ◽  
Suspension Parameters ◽  
Atomic Force ◽  
Size Of Particles ◽  
The Impact

Abstract Water from mining drainage is turbid because of suspensions. We tested the hypothesis that the chemical composition as well as shape and size of particles in suspensions of natural origin affect the density and functional diversity of zooplankton. The suspensions were analyzed with atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and optical microscopy. Elements found in the beidellite clays were also identified in the mineral structure of the particles. As the size of the microparticles decreased, the weight proportions of phosphorus, sulfur, and chlorine increased in the suspensions. These conditions facilitated the biomass growth of large and small microphages and raptorials. As the size of the nanoparticles decreased, the shares of silicon, aluminum, iron, and magnesium increased. These conditions inhibited raptorials the most. Ecosystem functionality was the highest with intermediate suspension parameters, which were at the lower range of the microphase and the upper range of the nanophase. The functional traits of zooplankton demonstrate their potential for use as sensitive indicators of disruptions in aquatic ecosystems that are linked with the presence of suspensions, and they facilitate gaining an understanding of the causes and scales of the impact of suspensions.

scholarly journals Link between Land Use and Flood Risk Assessment in Urban Areas

Proceedings ◽  
2020 ◽  
Vol 30 (1) ◽  
pp. 62
Author(s):  
Zahra Kalantari ◽  
Johanna Sörensen
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Green Infrastructure ◽  
Flood Risk ◽  
Urban Areas ◽  
Land Use Changes ◽  
Drainage System ◽  
Property Owners ◽  
Pluvial Flooding ◽  
The Impact

The densification of urban areas has raised concerns over increased pluvial flooding. Flood risk in urban areas might increase under the impact of land use changes. Urbanisation involves the conversion of natural areas to impermeable areas, causing lower infiltration rates and increased runoff. When high-intensity rainfall exceeds the capacity of an urban drainage system, the runoff causes pluvial flooding in low-laying areas. In the present study, a long time series (i.e., 20 years) of geo-referenced flood claims from property owners has been collected and analysed in detail to assess flood risk as it relates to land use changes in urban areas. The flood claim data come from property owners with flood insurance that covers property loss from overland flooding, groundwater intrusion through basement walls, as well as flooding from drainage systems; these data serve as a proxy of flood severity. The spatial relationships between land use change and flood occurrences in different urban areas were analysed. Special emphasis was placed on examining how nature-based solutions and blue-green infrastructure relate to flood risk. The relationships are defined by a statistical method explaining the tendencies whereby land use change affects flood risk.

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