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 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 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 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 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.

scholarly journals Unified Packing Model for Improved Prediction of Porosity and Hydraulic Conductivity of Binary Mixed Soils

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 455
Author(s):  
Ammar El-Husseiny
Keyword(s):  
Hydraulic Conductivity ◽  
Current Model ◽  
Fine Sand ◽  
Coarse Sand ◽  
Published Data ◽  
Soil Mixing ◽  
Packing Model ◽  
Wide Range ◽  
The Impact ◽  
Mixed Soils

Binary mixed soils, containing coarse sand particles mixed with variable content of fines (fine sand, silt, or clay) are important for several environmental and engineering applications. The packing state (or porosity) of such sand-fines mixtures controls several important physical properties such as hydraulic conductivity. Therefore, developing an analytical packing model to predict porosity of binary mixed soils, based on properties of pure unmixed sand and fines (endmembers), can contribute to predicting hydraulic conductivity for the mixtures without the need for extensive laboratory measurements. Toward this goal, this study presents a unified packing model for the purpose of predicting the porosity and hydraulic conductivity of binary mixed soils as function of fines fraction. The current model modifies an existing packing model developed for coarse binary mixed soils to achieve three main improvements: (1) being inclusive of wide range of binary mixed soils covering the whole range particle sizes, (2) incorporating the impact of cohesive packing behavior of the fines on binary mixture porosity, and (3) accounting for the impact of clay swelling. The presented model is the first of its kind incorporating the combined impact of all three factors: particle size ratio, fines cohesive packing and swelling, on binary mixtures porosity. The predictions of the modified model are validated using experimental published data for the porosity of sand-fines mixtures from 24 different studies. The model shows significant improvement in predicting porosity compared to existing packing models that frequently underestimate the porosity. By using the predicted porosity as an input in Kozeny–Carman formulation, the absolute mean error in predicting hydraulic conductivity, as function of fines fraction for 16 different binary mixed soils, is reduced by 50% when compared to the use of the previous packing model. The current model provides insights about the endmembers properties (porosity, hydraulic conductivity, and grain size) and fines content required to achieve a certain target desirable porosity and hydraulic conductivity of the mixed soils. This can assist the optimization of soil mixing design for various applications.

scholarly journals Selection of Drainage and Evaluation Used Filter Media

2020 ◽  
Vol 6 (3) ◽  
pp. 161-169
Author(s):  
J. Talybova
Keyword(s):  
Filter Material ◽  
Ground Layer ◽  
Filter Media ◽  
Normative Documents ◽  
Large Particles ◽  
Selection Of

The feature of running the suffosion of sand grounds in the top five-meter soil-ground layer where drainage is constructed on the basis of existing normative documents and granulo¬metric composition of filter material was determined with reports. The actual and report contents of the filter differ sharply. Large particles (40% by weight) of more than 20 mm should be sorted out from the sand-gravel ground to be used for construction of drainage.

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