scholarly journals Modelling 3D permeability distribution in alluvial fans using facies architecture and geophysical acquisitions

2016 ◽  
Author(s):  
Lin Zhu ◽  
Huili Gong ◽  
Zhenxue Dai ◽  
Gaoxuan Guo ◽  
Pietro Teatini
Keyword(s):  
Spatial Distribution ◽  
Hydraulic Conductivity ◽  
Flow Direction ◽  
Three Dimensional ◽  
Fine Sand ◽  
Coarse Sand ◽  
Alluvial Fan ◽  
Alluvial Fans ◽  
Statistical Parameters ◽  
Depositional Processes

Abstract. Alluvial fans are highly heterogeneous due to complex depositional processes, which make difficult to characterize the spatial distribution of the hydraulic conductivity K. An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional setting by using geological and geophysical data. The Chaobai River alluvial fan in the Beijing Plain, China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multi-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (Zone 1) to the lower (Zone 3) portion along the flow direction. In Zone 1, sediments were moved by higher-energy flooding, which induces bad sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from Zone 1 to Zone 3. The results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of K in alluvial fans.

scholarly journals Modeling 3-D permeability distribution in alluvial fans using facies architecture and geophysical acquisitions

2017 ◽  
Vol 21 (2) ◽  
pp. 721-733 ◽  
Author(s):  
Lin Zhu ◽  
Huili Gong ◽  
Zhenxue Dai ◽  
Gaoxuan Guo ◽  
Pietro Teatini
Keyword(s):  
Spatial Distribution ◽  
Hydraulic Conductivity ◽  
Flow Direction ◽  
Three Dimensional ◽  
Fine Sand ◽  
Coarse Sand ◽  
Alluvial Fan ◽  
Alluvial Fans ◽  
Statistical Parameters ◽  
Depositional Processes

Abstract. Alluvial fans are highly heterogeneous in hydraulic properties due to complex depositional processes, which make it difficult to characterize the spatial distribution of the hydraulic conductivity (K). An original methodology is developed to identify the spatial statistical parameters (mean, variance, correlation range) of the hydraulic conductivity in a three-dimensional (3-D) setting by using geological and geophysical data. More specifically, a large number of inexpensive vertical electric soundings are integrated with a facies model developed from borehole lithologic data to simulate the log10(K) continuous distributions in multiple-zone heterogeneous alluvial megafans. The Chaobai River alluvial fan in the Beijing Plain, China, is used as an example to test the proposed approach. Due to the non-stationary property of the K distribution in the alluvial fan, a multiple-zone parameterization approach is applied to analyze the conductivity statistical properties of different hydrofacies in the various zones. The composite variance in each zone is computed to describe the evolution of the conductivity along the flow direction. Consistently with the scales of the sedimentary transport energy, the results show that conductivity variances of fine sand, medium-coarse sand, and gravel decrease from the upper (zone 1) to the lower (zone 3) portion along the flow direction. In zone 1, sediments were moved by higher-energy flooding, which induces poor sorting and larger conductivity variances. The composite variance confirms this feature with statistically different facies from zone 1 to zone 3. The results of this study provide insights to improve our understanding on conductivity heterogeneity and a method for characterizing the spatial distribution of K in alluvial fans.

scholarly journals Heavy metal distribution in sediments around the offshore tin mining area of Central Bangka Regency, Indonesia

2021 ◽  
Vol 926 (1) ◽  
pp. 012027
Author(s):  
Irvani ◽  
S Adibrata ◽  
M Yusuf ◽  
M Hudatwi ◽  
A Pamungkas
Keyword(s):  
Heavy Metals ◽  
Spatial Distribution ◽  
Active Surface ◽  
Fine Sand ◽  
Mining Area ◽  
Pollution Load Index ◽  
Coarse Sand ◽  
Sieve Analysis ◽  
Marine Animals ◽  
Type Composition

Abstract Vary heavy metals scattered in suspension loads and re-sedimentation from the tailing of the offshore-alluvial tin mining at Tanah Merah and its surroundings, Central Bangka Regency. Research is needed to determine the type, composition, spatial distribution of heavy metals, and potential pollution. The active surface-sediments were taken from shallow marine systematically around the offshore tin mining area in the east season. Geochemical analysis of sediment using x-ray fluorescence, coupled with minerals and sieve analysis, and support by spatial analysis. These sediments have dominant the sand-size (range very-fine sand to coarse sand) and silt, contained predominantly large quantities of quartz minerals and shell fragments of marine animals. The metals are in the following decreasing order: Cr>Zn>Pb>Ni>Cu>As>Co>Cd. The spatial distribution of heavy metals generally has a relatively south, east, and north position, with concentrations occurring along the coastline and showing the degradation composition towards the open sea. The marine sediments are uncontaminated to moderately contaminated by Cd and Pb, indicate both natural and anthropogenic enrichment, low the pollution load index (PLI), and have various potential ecological risks index (RI) (low to very high RI).

scholarly journals Dust Particle Size and Statistical Parameters

2021 ◽  
pp. 57-93
Author(s):  
Noor Al-Dousari ◽  
Modi Ahmed ◽  
Ali Al-Dousari ◽  
Musaad Al-Daihani ◽  
Murahib Al-Elaj
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Size Distribution ◽  
Fine Sand ◽  
Coarse Sand ◽  
Optical Methods ◽  
Size Analysis ◽  
Coarse Silt ◽  
Statistical Parameters ◽  
Fine Silt

AbstractGrain ‘size’ can be specified and measured in several different ways. All methods of grain size determination have blemishes, and the choice of the most appropriate method is governed by the nature of the sample and the use to which the data are placed. Four main methods are currently used for size analysis of sands: (a) sieving; (b) settling tube analysis; (c) electro-optical methods, including Coulter Counter analysis and laser granulometry; and (d) computerized image analysis. The classification of the particle size distribution of Kuwait dust was mapped according to the parameters proposed by Folk And Ward (1957) which were widely used for quantitative comparisons between natural grain size distribution and the lognormal distribution that shows better sorted sediments have lower values of σ1. Maps of the distribution of dust in Kuwait were obtained that included: fine sand (F.S.), Coarse sand (C.S), Medium Sand (M.S), Very Fine Sane (V.F.S), Very Coarse Silt (V.C.Silt), Coarse Silt (C.Silt), Medium Silt (M.Silt), Fine Silt (F.Silt), Very Fine Silt (V.F.Silt), in addition to that, the deposition percentage of Clay, Sand, mud (silt plus clay) and silt were provided.

scholarly journals Alluvial-eolian interaction in a Cambrian rift margin: the Pedra das Torrinhas and Pedra Pintada formations (Guaritas Group, RS)

2009 ◽  
Vol 81 (4) ◽  
pp. 819-836 ◽  
Author(s):  
André Marconato ◽  
Renato P. Almeida ◽  
Maurício G. M. Santos ◽  
Jorge E.S. Nóbrega ◽  
Rogério B. Souza
Keyword(s):  
Spatial Distribution ◽  
Sedimentary Facies ◽  
Alluvial Fan ◽  
Terrestrial Plants ◽  
Element Analysis ◽  
Heterogeneous Distribution ◽  
Sedimentary Petrography ◽  
Depositional Processes ◽  
Lower Porosity ◽  
Porosity Analysis

This work presents a study of selected outcrops from the Pedra das Torrinhas Formation of the Guaritas Group (Cambrian, Camaquã Basin), near the basin bordering Encantadas Fault Zone. The studied succession includes alluvial fan deposits that pass laterally into eolian deposits. Sedimentary facies and architectural element analysis were performed, followed by sedimentary petrography and microscopic porosity analysis, aiming to characterize the porosity of the deposits and its spatial distribution. The main objective was to contribute to a better understanding of the porosity spatial distribution in depositional systems characterized by the interaction between alluvial and eolian processes, with special reference to deposits formed prior to the development of terrestrial plants. Porosity values are related to depositional processes, with higher porosities associated to eolian dune deposits (mean of 8.4%), and lower porosity related to interdunes (mean of 3.4%) and alluvial fans (mean of 4.3%). Architectural elements analysis revealed the spatial relationships of these deposits, a response to the interplay of the eolian and alluvial processes. The integration of porosity data reveals that the interaction of alluvial and eolian processes results in heterogeneous distribution of porosity at the facies association scale. Eolian reworking of alluvial facies increases porosity whereas sheet-flood and other alluvial processes in the interdune areas reduce porosity.

scholarly journals Experimental study on filter media using locally available materials in bioretention

2019 ◽  
Vol 68 (8) ◽  
pp. 757-768 ◽  
Author(s):  
Feikai Yang ◽  
Rajendra Prasad Singh ◽  
Dangfang Fu
Keyword(s):  
Hydraulic Conductivity ◽  
Filter Material ◽  
Fine Sand ◽  
Yangtze River Delta ◽  
Coarse Sand ◽  
Easy Access ◽  
Filter Media ◽  
Local Climate ◽  
Yangtze River Delta Region ◽  
Selection Of

Abstract Bioretention systems and selection of effective filter media are very important in implementation of sponge cities. The current study was carried out to find proper composition of filter media using locally available materials, which acclimate to the special/local climate, environmental and geographical conditions in Yangtze River Delta region. Results revealed that sand with discontinuous gradation and containing a certain amount of clay led to unsatisfactory hydraulic performance (hydraulic conductivity ranged from 423 mm/h to 1,054 mm/h, and 1,500 mm/h to 29 mm/h). In contrast, a mixture of locally available sand, which consisted of continuous gradation of coarse sand (40–70%, by mass), fine sand (0–40%, by mass), very fine sand (10–60%, by mass) and nutrient soil (0–3%, by mass), had a hydraulic conductivity ranging from 200 to 400 mm/h and relatively stable structure. During the 70 days' flooding test, the hydraulic conductivity changed in the first 20 days due to the migration of particles (mainly <0.6 mm) and then became stable; the stable value was close to the initial. Moreover, easy access and simple production processes made it easier to promote. Findings could be used as a guideline for implementation of bioretention systems and selection of locally available and effective filter material.

scholarly journals Groundwater Simulation and Wells Distribution at Qazaniyah City in Diyala Governorate

2020 ◽  
Vol 26 (9) ◽  
pp. 95-113
Author(s):  
Majed Rodhan Huseen ◽  
Basim Sh. Abed
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Modeling ◽  
Three Dimensional ◽  
Alluvial Fan ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Main Layer ◽  
Operating Rate ◽  
Gis Software ◽  
Observation Wells

In recent years, there is more interest in water sources availability, including groundwater due to an increase in demand for water because of the increasing population in the world, and the water recedes due to climate change also. Therefore, the study of groundwater has required more attention. The aim of the present study is to establish a MODFLOW model in the groundwater modeling system software to simulate the movement of groundwater in the Turssaq alluvial fan which is located in the Qazaniyah city, east of Diyala Governorate. The solid model was used to define the aquifer in the study area. Using the GIS software, mapping and preparing the data needed to create a conceptual model were carried out. The data of the wells were used to create and define the aquifer, then a three-dimensional model was created. Measuring the water table for some wells were simultaneously monitored to determine the hydraulic conductivity values ​​of the aquifer through the (PEST) package provided by the software. The hydraulic conductivity value of the main layer was 18 m/d. Then several readings of observation wells were recorded for the period extended from 1/Nov/2018 to 22/May/2019 for the calibration process in the unsteady situation and to determine the coefficient of storage. The value of the storage coefficient was defined as 0.001. Several scenarios were conducted for the study area to find the best distance between the wells. Three distances were tested, 500, 1000 and 1500 m. The operating periods were 6, 12 and 18 (hours/day). Results obtained from the model show that the best distance between the wells is 1000 meters with a maximum operating rate of 12 hours/day. The maximum discharge with the lowest distance and the lowest drawdown of the groundwater table are considered.

scholarly journals Fabrication of Permeameter for Determination of Hydraulic Conductivity of Earth Materials

2020 ◽  
Vol 9 (4) ◽  
pp. 1204-1210
Keyword(s):  
Hydraulic Conductivity ◽  
Engineering Design ◽  
Low Cost ◽  
Pressure Head ◽  
Fine Sand ◽  
Coarse Sand ◽  
Silty Clay ◽  
Earth Dams ◽  
Soil Hydraulic Conductivity

Laboratory investigation is one of the major ways of assessing soil hydraulic conductivity. Determination of hydraulic conductivity aids in engineering design of well pumping, prediction concerning spread of polluting fluids, embankment of canal bank affected by seepage, flooding solutions and stability of earth dams. However, different studies have shown that there are alternative models to Darcy’s law which governs the widely use of laboratory measurement of hydraulic conductivity. The deficiencies accustomed to the conventional permeameter such as the time wastage and cost-intensivehas led to different research modification. A low-cost permeameter was fabricated using a plastic column, hose pipe, to serve as water inlet and outlet connected to two manometer tubes to measure the pressure head difference. The hydraulic conductivities measured using the lowcost were 4.31 cm/s, 8.14 cm/s, 6.12 cm/s, 5.86 cm/s for 0.3 mm coarse sand, 0.85-1 mm fine sand, sandy clay and silty clay respectively. In comparison of the fabricated permeameter with conventional permeameter and other fabricated laboratory permeameters, it was observed that the hydraulic conductivity obtained is consistent with the typical permeability range for each soil type.

scholarly journals Spatial distribution of bivalvia (Mollusca) in the soft-bottoms of Ilha Grande Bay, Rio de Janeiro, Brazil

1998 ◽  
Vol 46 (1) ◽  
pp. 19-31 ◽  
Author(s):  
Maria Cláudia Guimarães Grillot ◽  
Carlos Renato R. Ventura ◽  
Sérgio Henrique Gonçalves da Silva
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Rio De Janeiro ◽  
Fine Sand ◽  
Structural Heterogeneity ◽  
Coarse Sand ◽  
Bivalve Molluscs ◽  
Soft Bottoms

The spatial distribution of bivalve molluscs and its relation to granulometry and to the percentage of organic matter and silt-clay were studied in the Saco do Céu Inlet. Bivalves and samples of sediment were collected in 39 stations, in January and July 1992, using a 0.1 m2 Petersen grab. The type of sediment varied from very fine to coarse sand. Nineteen species of bivalves were quantified, 14 of which were present in the two periods of the year. The highest diversity was found in medium and fine sand in summer and in coarse sand in winter. These bottoms presented a greater structural heterogeneity. A community dominated by Corbula caribaea was distinguished in fine bottoms with relative high content of organic matter, whereas another community dominated by Anomalocardia brasiliana occurred in coarser bottoms. Both communities were distributed in continuum along a sediment gradient.

scholarly journals Sediment type and breeding strategy of the Bank Swallow Riparia riparia in western Sweden

Ornis Svecica ◽  
2002 ◽  
Vol 12 (3) ◽  
pp. 157-163
Author(s):  
Bo-Bertil Lind ◽  
Jimmy Stigh ◽  
Lars Larsson
Keyword(s):  
Hydraulic Conductivity ◽  
Bulk Density ◽  
Fine Sand ◽  
Coarse Sand ◽  
Breeding Strategy ◽  
Sediment Type ◽  
Medium Sand ◽  
Riparia Riparia ◽  
Bank Swallow ◽  
Sand Pits

This paper presents an investigation of the sediment used by the Bank Swallow (Sand Martin) Riparia riparia for the construction of breeding tunnels. Grain-size distribution, bulk density and hydraulic conductivity of breeding-tunnel sediment were investigated at four localities in western Sweden. The investigation shows that the Bank Swallow was consistent in using layers composed of a narrow range of fine and medium sand. Ninety percent of the investigated breeding burrows were located in fine to medium sand (0.125–0.5 mm) and 10% in coarse sand (0.5–1.0 mm). No breeding tunnels were found in sediment finer than fine sand or coarser than coarse sand. The fine to medium sand fraction has the properties to hold stable walls and keep dry tunnels even during rainy periods with heavy infiltration. The hydraulic conductivity of the sediment was in the range of 10–4 to 10–3 m/s and the bulk density 1,510–1,575 kg/m3. In Sweden, artificially excavated slopes in gravel and sand pits have long been the dominating breeding locality for the Bank Swallow. However, during the last two decades, four major factors have led to the decrease of breeding localities: (1) a decreasing demand of aggregate resources, (2) landscaping of gravel and sand pits and stabilization of eroding slopes, including river banks and shorelines, (3) a change to quarries as a source for aggregate production, and (4) concentrating gravel and sand exploitation to fewer and larger pits. It is concluded that these factors are important for the decline of the Bank Swallow population in Sweden and possibly elsewhere in Europe and North America.

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