scholarly journals CONTRIBUTION TO HYDRAULIC CHARACTERISTICS OF PLIO-PLEISTOCENE DEPOSITS OF THRIASSION PLAIN OF ATTICA

2017 ◽  
Vol 50 (2) ◽  
pp. 967 ◽  
Author(s):  
D. Hermides ◽  
T. Mimides ◽  
G. Stamatis
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Specific Capacity ◽  
Geological Structure ◽  
Hydraulic Characteristics ◽  
Dry Period ◽  
Tectonic Structures ◽  
Pumping Tests ◽  
Recovery Method ◽  
Hydrogeological Conditions

The geological structure of Thriassion Plain is generally complex and has been affected at different times by many tectonic activities. The last ones are the neotectonic, which caused horsts and grabens structures. Geologic and tectonic structures have influenced the hydrogeological conditions and the groundwater flow. Hydraulic characteristics of Plio-Pleistocene deposits differ throughout their extent. In this study, pumping tests in Plio-Pleistocene deposits are represented and the hydraulic characteristics transmissivity T, storativity S and hydraulic conductivity K are assigned. Pumping tests, in 8 totally wells, were conducted in the dry period. Methods as Cooper-Jacob’s, Theis’s, Papadopoulos Cooper’s and Neuman’s and last the Recovery method, are used to assign the hydraulic characteristics. These tests highlighted the Recovery method as the most reliable. Transmissivity T: 18-279.1 m2/d, storativity S: 2.5*10-3 3*10-2and hydraulic conductivity K: 0.4-25.1 m/d. Specific capacity is also determined ranging between 16-360 m3/d/m. This study contributes, essentially, in the approach of hydrogeological conditions of Thriassion Plain.

scholarly journals Modeling Spatial Distribution of 2D Anisotropic Hydraulic Conductivity Tensor of Fractured Groundwater Flow Media using Neural Network Case Study Grasberg Open Pit of PTFI and Surrounding

2017 ◽  
Author(s):  
Adam Verdyansyah Putra ◽  
Tedy Agung Cahyadi ◽  
Lilik Eko Widodo ◽  
Eman Widijanto
Keyword(s):  
Neural Network ◽  
Spatial Distribution ◽  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Geological Structure ◽  
Conductivity Tensor ◽  
Open Pit ◽  
Two Dimensional ◽  
Fracture Mapping ◽  
Anisotropic Hydraulic Conductivity

Highly fractured rocks in Grasberg open pit and surrounding of PT Freeport Indonesia (PTFI) result in fractured groundwater flow media. It is due to the complex geological structure and lithological condition. Accordingly, it leads to anisotropic distribution of hydraulic conductivity. The paper will be devoted tothe modeling of two dimensional (2D) spatial distribution of hydraulic conductivity using neural network. Surface fracture mapping database will be used to estimate 2D equivalent anisotropic hydraulic conductivity tensor based on the Oda et al (1996) approach. Modeled anisotropic hydraulic conductivity is then checked at some points where the slug tests for isotropic conductivity are observed. Co-relation, validation and training between modeled and observed hydraulic conductivity is then carried out using transformation of vector anisotropic hydraulic conductivity into the scalar isotropic hydraulic conductivity. Following training step, neural network will then generate two dimensional model of anisotropic hydraulic conductivity distribution. It is beneficial for modeling of shallow anisotropic flow of groundwater distribution

scholarly journals Geological and groundwater flow model of a submarine groundwater discharge site at Hanko (Finland), northern Baltic Sea

2021 ◽  
Author(s):  
Samrit Luoma ◽  
Juha Majaniemi ◽  
Arto Pullinen ◽  
Juha Mursu ◽  
Joonas J. Virtasalo
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Baltic Sea ◽  
Submarine Groundwater Discharge ◽  
Flow Model ◽  
Groundwater Discharge ◽  
Coarse Grained ◽  
Local Geometry ◽  
Groundwater Flow Model ◽  
Submarine Groundwater

AbstractThree-dimensional geological and groundwater flow models of a submarine groundwater discharge (SGD) site at Hanko (Finland), in the northern Baltic Sea, have been developed to provide a geological framework and a tool for the estimation of SGD rates into the coastal sea. The dataset used consists of gravimetric, ground-penetrating radar and shallow seismic surveys, drill logs, groundwater level monitoring data, field observations, and a LiDAR digital elevation model. The geological model is constrained by the local geometry of late Pleistocene and Holocene deposits, including till, glacial coarse-grained and fine-grained sediments, post-glacial mud, and coarse-grained littoral and aeolian deposits. The coarse-grained aquifer sediments form a shallow shore platform that extends approximately 100–250 m offshore, where the unit slopes steeply seawards and becomes covered by glacial and post-glacial muds. Groundwater flow preferentially takes place in channel-fill outwash coarse-grained sediments and sand and gravel interbeds that provide conduits of higher hydraulic conductivity, and have led to the formation of pockmarks on the seafloor in areas of thin or absent mud cover. The groundwater flow model estimated the average SGD rate per square meter of the seafloor at 0.22 cm day−1 in autumn 2017. The average SGD rate increased to 0.28 cm day−1 as a response to an approximately 30% increase in recharge in spring 2020. Sensitivity analysis shows that recharge has a larger influence on SGD rate compared with aquifer hydraulic conductivity and the seafloor conductance. An increase in recharge in this region will cause more SGD into the Baltic Sea.

GEOPOLIS software tools – Groundwater flow modeling at deep repository of liquid radioactive waste at Severny test site

2021 ◽  
pp. 91-97
Author(s):  
V. V. Suskin ◽  
A. V. Rastorguev ◽  
I. V. Kapyrin
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Liquid Radioactive Waste ◽  
Three Dimensional ◽  
Test Site ◽  
Geological Structure ◽  
Groundwater Flow Model ◽  
Flow Modeling ◽  
Three Dimensional Model ◽  
Groundwater Flow Modeling

This article discusses a three-dimensional groundwater flow model of a deep disposal facility at Severny test site. The three-dimensional model is a part of the certified software GEOPOLIS, based on the hydrogeological code GeRa (Geomigration of Radionuclides) serving as the calculation engine. This study describes the hydrogeological patterning of the groundwater flow model, as well as the results of calibration and verification of the model water heads with respect to the data of monitoring for more than 40 years of the deep repository exploitation. The article begins with a brief overview of the previously developed hydrogeological models of this object and continues with a description of the geological structure of the territory, and with a substantiation of the boundaries and parameters of the model. The results of groundwater flow modeling, model calibration, verification and estimation of discrepancy between the model results and monitoring data are shown. The comparison of the modeled and observed water heads in the stationary conditions (before the start of injection) and during operation of the deep repository allows making conclusion on the quality of calibration.

scholarly journals Hydrogeological Conditions of Qazaniyah Sub-basin in Diyala / Iraq

2021 ◽  
pp. 3921-3931
Author(s):  
Zahraa. M. Muhsin ◽  
Qusai .Y. Al-Kubaisi
Keyword(s):  
Hydraulic Properties ◽  
Specific Capacity ◽  
Sedimentary Rocks ◽  
Storage Coefficient ◽  
Hydrogeological Conditions ◽  
And Storage

The study area is located in the eastern part of the Diyala Governorate close to the Iraqi-Iranian border. This study was set to investigate the hydrogeological calculations of northeast of Qazaniyah wells where the groundwater moves in directions of from the northeastern parts towards the southwestern par, that is, the same direction of the topography and the same direction of the tendency of the layers t. The study‘s region is characterized by visible geological layers or those that can be penetrated to a reasonable depth by wells which are sedimentary rocks deposited in continental or semi-continental conditions in the bays. From the study of the hydraulic properties of the two hydrogeological and exemplary systems, the values of transmissivity, permeability and storage coefficient are ranged between 1.94- 5.73 m2/day, 1.02- 3.92 m/day and1.40 x 10-5- 2.62 x 10-4, respectively. While the estimated value of transmissivities, which are obtained from specific capacity, ranged between 6.27- 8.62 m2/day. This variance in the values indicates the broad differences in the values Lithology of aquifers, which seems to be influenced by the strength and the number of fractures and joints.

scholarly journals Factors Affecting Runoff Retention Performance of Extensive Green Roofs

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1217 ◽  
Author(s):  
Yongwei Gong ◽  
Dingkun Yin ◽  
Xing Fang ◽  
Junqi Li
Keyword(s):  
Hydraulic Conductivity ◽  
Retention Rate ◽  
Green Roofs ◽  
Retention Performance ◽  
Dry Period ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Drainage Layer ◽  
Factors Affecting ◽  
Extensive Green Roofs

The runoff retention effectiveness of 10 extensive green roof (EGR) modules (100 mm substrate planted Sedum lineare Thunb.) were analyzed in Beijing for 22 rainfall events (2.4–46.4 mm) from 1 July to 30 September 2017. Differences between minimum inter-event dry periods, module scales, substrate hydraulic conductivity and depths, drainage layer types and rainfall characteristics were examined to study their correlation to the retention performance of EGRs. In general, EGRs with lower substrate hydraulic conductivity, deeper substrate and lower rainfall depth had higher runoff retention performance. By comparsion, no siginificant correlation was found between rainfall duration, prior dry period, average rainfall intensity, drainage layer type and EGR runoff retention rate. Analyses of variance (ANOVA) and Tukey tests supported these results. Low or moderate rainfall (<15 mm) may or may not have an effect, but heavy rainfall (>25 mm) definitely affects the EGR retention performance of the next rainfall event.

GEOLOGICAL STRUCTURE OF THE SURFACE OF THE PALEOZOIC FOLDED BASE OF THE WEST OF THE TURAN PLATFORM

2021 ◽  
Vol 82 (3) ◽  
pp. 19-26
Author(s):  
POPKOV VASILY I. ◽  
Keyword(s):  
Surface Structure ◽  
Oil And Gas ◽  
Geological Structure ◽  
Comprehensive Analysis ◽  
Tectonic Structures ◽  
The West ◽  
Seismic Surveys ◽  
Gravity And Magnetic ◽  
Morphostructural Zoning ◽  
Gas Potential

The surface of the folded base of the platforms is an important geological boundary separating rock complexes formed in different geodynamic settings and characterized by different physical properties, which largely determine the patterns of formation of minerals in them. Therefore, determining the depth of its occurrence and morphology is not only theoretical, but also practical. Despite many years of studying the foundation of the west of the Turan Platform, there is no unity among geologists and geophysicists in their ideas about its structure, depth of occurrence and surface structure. In this regard, the aim of the work is to build a structural map of the surface of the foundation of the west of the Turan plate, to identify the main tectonic structures and their morphology. The construction is based on a comprehensive analysis of drilling materials and geophysical data. When drawing up the structural map, all the currently available geological and geophysical material was used, including data from drilling, gravity and magnetic surveys, and seismic surveys of various modifications, which made it possible to perform fairly detailed and reliable constructions. The article provides a detailed description of the surface structure of the folded base of the west Turan platform. The obtained results can be used in solving the issues of oil and gas potential of the studied territory. The folded base of the western Turan plate is a heterogeneous and heterochronous formation, differentiated by the depth of occurrence, which allows for morphostructural zoning of its surface.

scholarly journals Groundwater flow below construction pits and erosion of temporary horizontal layers of silicate grouting

2020 ◽  
Vol 28 (8) ◽  
pp. 2821-2832
Author(s):  
Joris M. Dekker ◽  
Thomas Sweijen ◽  
Alraune Zech
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Analytical Solutions ◽  
Mass Flux ◽  
Approximate Solutions ◽  
Sensitivity Study ◽  
Advective Transport ◽  
Dilution Ratio ◽  
The Impact ◽  
Horizontal Layers

AbstractInjection of silicate grouting materials is widely used to create temporary horizontal layers for reducing inflow of groundwater at construction sites, in regions with shallow water tables. The erosion of a grouting layer was investigated by means of analytical solutions for groundwater flow and transport within a pit after construction finished. Erosion is assumed to occur by dissolution of the temporary injection layer and subsequent advective transport. Thereby, the hydraulic conductivity changes with time. This paper presents novel analytical solutions and approximate solutions for the major fluxes in the construction pit as a function of the domain settings, aquifer gradient and hydraulic conductivity. In addition, the mass flux and the dilution ratio of erosion-related components leaving the construction pit and entering the aquifer are quantified. Derived solutions are verified against numerical simulations. A sensitivity study shows the impact of domain settings on fluxes and dilution ratio. The results confirm that mass flux of grout components increases with ongoing erosion. Thus, its effect on groundwater quality increases with time after construction ceased.

Distribution, origin, and hydraulic influence of fractures in a clay-rich glacial deposit

1995 ◽  
Vol 32 (6) ◽  
pp. 957-975 ◽  
Author(s):  
L.D. McKay ◽  
J. Fredericia
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Key Words ◽  
Water Table ◽  
Stress Relief ◽  
Fracture Density ◽  
Lacustrine Environment ◽  
Tritium Content ◽  
Glacial Deposit ◽  
A Site

In the unconsolidated clay-rich glacial deposits underlying a site in southwestern Ontario, fractures and root casts greatly influence hydraulic conductivity and groundwater flow. The fractures are predominantly vertical and have visible oxidation staining from surface to a depth of 6 m. Root casts commonly occur along fracture surfaces in the upper 3 m, but can also occur as holes in apparently unfractured blocks. The fractures are believed caused mainly by dessication during past periods of low water table. This hypothesis is supported by a decrease in fracture density with depth and the presence of a stiff crust, presumably caused by desiccation-induced consolidation. The random pebble fabric and faint layering indicate deposition in a calm lacustrine environment, which precludes the possibility of the fractures having been caused by overriding ice. Fractures were found below the depth of oxidation staining (6 m) but most of these appear to have been caused by stress-relief due to the excavation and subsequent drying. In the upper 3 m the fractures and root casts are responsible for field-measured hydraulic conductivity values that are up to 3 orders of magnitude greater than measured in the laboratory for samples of the unfractured matrix. High values of field-measured hydraulic conductivity, seasonal head variations greater than 0.5 m, and high tritium content all persist below the depth of root casts, indicating that hydraulically conductive fractures do exist to depths of at least 6 m and possibly as great as 12–15 m, which is well below the depth of oxidation staining. However, there is some uncertainty in this assessment of the extent of hydraulically conductive fractures because of the sensitivity to small leaks in the piezometer installations. Key words : clay, glacial, fractures, desiccation, hydraulic conductivity.

Statistical analysis of the geological–hydrogeological conditions within part of the Eye–Dashwa Pluton, Atikokan, northwestern Ontario

1989 ◽  
Vol 26 (2) ◽  
pp. 345-356
Author(s):  
P. A. Brown ◽  
N. A. C. Rey
Keyword(s):  
Hydraulic Conductivity ◽  
Linear Regression Analysis ◽  
Filling Material ◽  
Predictive Capability ◽  
Filling Materials ◽  
Northwestern Ontario ◽  
Hydrogeological Conditions ◽  
Regression Design ◽  
R Value ◽  
Lower Temperature

The occurrence and distribution of fracture-filling material within the Eye–Dashwa granite indicate that the dominant fracture system formed shortly after emplacement and cooling of the pluton at 2678 ± 67 Ma. Subsequent reactivation of these ancient fractures was accompanied by sequentially younger and lower temperature filling materials. These reopened ancient fractures are best developed in the upper 300–400 m of the rock mass and are commonly conduits for present-day groundwater flow.Multiple linear regression analysis performed on the geological variables defined from boreholes ATK-1, -2, -3, -4, and -5 identified a highly significant correlation between a number of these variables and hydraulic conductivity values measured in 25 m test sections of the boreholes. The correlation is expressed as[Formula: see text]here log Kerm is the log of hydraulic conductivity; log(DEPTH) is the log-transformed depth to the lower end of the packer interval; log(CLAY) is the log-transformed frequency of clay-filled fractures per 25 m interval; log(VEIN) is the log-transformed frequency of veins per 25 m interval. The equation has a multiple r value of 0.82, explains 67% of the variance of hydraulic conductivity, and has a random exceedence probability (Q) of 9 × 10−12 (i.e., it is highly significant).The predictive capability of the regression design was tested with seven new test data and found to be a valid estimator of the hydrogeological conditions within these test intervals.

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