scholarly journals Using water level and temperature time series to improve hydrogeological parameterization in a complex alluvial system

2019 ◽  
Author(s):  
Luca Vettorello ◽  
Andrea Sottani
Keyword(s):  
Hydraulic Conductivity ◽  
Unconfined Aquifer ◽  
Open Pit ◽  
Homogeneous Distribution ◽  
Groundwater Temperature ◽  
Pumping Tests ◽  
Groundwater Exploitation ◽  
Phreatic Aquifer ◽  
Depth Analysis ◽  
High Level

A new pumping station was designed in the northern high plain of the province of Padua (Veneto region, north-eastern Italy), aiming to reach an overall abstraction rate of about 2 m3/s, in order to relevantly contribute to the regional drinking water supply. Local unconfined aquifer is a highly permeable alluvial system, hydraulically connected to the Brenta river, one of the most important groundwater recharging sources of the entire hydrogeological basin, and the Camazzole lake, a former open-pit mine. This lake deepens below the water table and is directly connected to the surrounding phreatic aquifer and indirectly to the river, forming a 3-element hydraulic equilibrium. In order to evaluate the sustainability of the groundwater exploitation, this case study required an in-depth analysis of the hydrogeological resource, focusing on the estimation of hydraulic conductivity values and distribution. A numerical simulation was needed since the first step of the study, to plan the following field activities and provide a rough representation of the expectable drawdown in the pumped aquifer, even if the initial model had a very high level of uncertainty. Before the pumping tests no experimental data were available, so a homogeneous distribution of hydraulic conductivity was preliminarily assigned to the entire mesh, referring to a single bibliographic value available for the aquifer. After the analytical interpretation of pumping tests, different punctual values of hydraulic conductivity were estimated, but the parameter field was still very difficult to define, due to the complexity of the hydrogeological context and the non-uniqueness of the possible spatial interpolations. The availability of groundwater level observations at a larger scale allowed to calculate a set of hydraulic conductivity fields through the pilot points method, integrating the pumping tests results and extending aquifer characterization to a wider domain. The numerical model was finally calibrated with groundwater temperature monitored trends, reproducing the interaction between the lake and the phreatic aquifer through a heat transport simulation. The resulting hydraulic conductivity distribution has been considerably refined, especially at the interface between the lake and the aquifer, and the parameterization has been further validated using heat as a groundwater tracer.

scholarly journals Stochastic analysis of the hydraulic conductivity estimated for a heterogeneous aquifer via numerical modelling

2015 ◽  
Vol 368 ◽  
pp. 472-477
Author(s):  
C. Lu ◽  
Y. Zhang ◽  
L. Shu ◽  
X. Chen ◽  
S. Chen ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Karst Aquifer ◽  
Unconfined Aquifer ◽  
Pumping Tests ◽  
Heterogeneous Aquifer ◽  
The Monte Carlo Method ◽  
The Mean ◽  
Theis Solution ◽  
Observation Wells ◽  
The Impact

Abstract. The paper aims to evaluate the impacts of the average hydraulic conductivity of the heterogeneous aquifer on the estimated hydraulic conductivity using the observations from pumping tests. The results of aquifer tests conducted at a karst aquifer are first introduced. A MODFLOW groundwater flow model was developed to perform numerical pumping tests, and the heterogeneous hydraulic conductivity (K) field was generated using the Monte Carlo method. The K was estimated by the Theis solution for an unconfined aquifer. The effective hydraulic conductivity (Ke) was calculated to represent the hydraulic conductivity of a heterogeneous aquifer. The results of numerical simulations demonstrate that Ke increase with the mean of hydraulic conductivity (EK), and decrease with the coefficient of variation of the hydraulic conductivity (Cv). The impact of spatial variability of K on the estimated Ke at two observation wells with smaller EK is less significant compared to the cases with larger EK.

scholarly journals Mapping Groundwater Seepage in a Fen Using Thermal Imaging

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Ogochukwu Ozotta ◽  
Philip J. Gerla
Keyword(s):  
Hydraulic Conductivity ◽  
Thermal Imaging ◽  
Crucial Role ◽  
Groundwater Discharge ◽  
Late Summer ◽  
Groundwater Temperature ◽  
Groundwater Seepage ◽  
Heterogeneous Soil ◽  
Hydraulic Gradients ◽  
Warm Soil

The transport of dissolved minerals and groundwater flow plays a crucial role in the ecosystem of many wetlands. Nonetheless, installing equipment to monitor groundwater seepage is invasive, harms vegetation, and can impact biodiversity. By remotely mapping surface temperature in late summer, when there is the greatest difference between warm soil and cold groundwater, temperature patterns can expose areas with the greatest upward gradient and flow. The conventional method of using tensiometers to measure hydraulic gradient and estimate flux using Darcy’s law was applied and compared with thermal imaging to characterize groundwater seepage at two contrasting sites within a central North Dakota fen (groundwater discharge wetland). Both sites exhibited variable gradients between the shallow and deep tensiometers. The temperature trend determined from the thermal imaging showed a closer relationship to the measured hydraulic gradients at the herbaceous (Sedge) site than at the wooded (Willow) site. Saturated hydraulic conductivity K ranged from 6 × 10−5 to 2 × 10−4 m/s for the Willow site; and 6 × 10−6 to 1 × 10−4 m/s for Sedge site. The flux calculated for the Willow site ranged from 1.4 × 10−5 to 2.7 × 10−4 m/s and that of the Sedge site ranged from 2.2 × 10−6 to 6.3 × 10−5 m/s. The gradients are affected at shallow depth because of heterogeneous soil stratigraphy, which is likely the reason that seepage faces at the sites cannot be mapped solely by thermal imaging.

scholarly journals New insights into the drainage of inundated ice-wedge polygons using fundamental hydrologic principles

2021 ◽  
Author(s):  
Dylan R. Harp ◽  
Vitaly Zlotnik ◽  
Charles J. Abolt ◽  
Brent D. Newman ◽  
Adam L. Atchley ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Aspect Ratio ◽  
Annular Region ◽  
Active Layer Thickness ◽  
Conductivity Anisotropy ◽  
Aspect Ratios ◽  
High Anisotropy ◽  
Vertical Hydraulic Conductivity ◽  
Depth Analysis ◽  
Ice Wedge

Abstract. The pathways and timing of drainage from inundated ice-wedge polygon centers in a warming climate have important implications for carbon flushing, advective heat transport, and transitions from carbon dioxide to methane dominated emissions. This research provides intuition on this process by presenting the first in-depth analysis of drainage from a single polygon based on fundamental hydrogeological principles. We use a recently developed analytical solution to provide a baseline for the effects of polygon aspect ratios (radius to thawed depth) and hydraulic conductivity anisotropy (horizontal to vertical hydraulic conductivity) on drainage pathways and temporal depletion of ponded water heights of inundated ice-wedge polygon centers. By varying the polygon aspect ratio, we evaluate the effect of polygon size (width), inter-annual increases in active layer thickness, and seasonal increases in thaw depth on drainage. One of the primary insights from the model is that most inundated ice-wedge polygon drainage occurs along an annular region of the polygon center near the rims. This implies that inundated polygons are most intensely flushed by drainage in an annular region along their horizontal periphery, with implications for transport of nutrients (such as dissolved organic carbon) and advection of heat towards ice wedge tops. The model indicates that polygons with large aspect ratios and high anisotropy will have the most distributed drainage. Polygons with large aspect ratio and low anisotropy will have their drainage most focused near the their periphery and will drain most slowly. Polygons with small aspect ratio and high anisotropy will drain most quickly. Our results, based on idealized scenarios, provide a baseline for further research considering geometric and hydraulic complexities of ice-wedge polygons.

Estimation of hydraulic conductivity of an unconfined aquifer using cokriging of GPR and hydrostratigraphic data

2001 ◽  
Vol 47 (2) ◽  
pp. 135-152 ◽  
Author(s):  
Erwan Gloaguen ◽  
Michel Chouteau ◽  
Denis Marcotte ◽  
Robert Chapuis
Keyword(s):  
Hydraulic Conductivity ◽  
Unconfined Aquifer

scholarly journals Hydrophobic Forces Are Relevant to Bacteria-Nanoparticle Interactions: Pseudomonas putida Capture Efficiency by Using Arginine, Cysteine or Oxalate Wrapped Magnetic Nanoparticles

2018 ◽  
Vol 2 (3) ◽  
pp. 29 ◽  
Author(s):  
Federico Figueredo ◽  
Albert Saavedra ◽  
Eduardo Cortón ◽  
Virginia Diz
Keyword(s):  
Amino Acid ◽  
Pseudomonas Putida ◽  
Surface Characteristics ◽  
Magnetic Core ◽  
Capture Efficiency ◽  
Homogeneous Distribution ◽  
Infrared Spectrometry ◽  
Ideal Situation ◽  
High Level ◽  
Surface Modified

Size, shape and surface characteristics strongly affect interfacial interactions, as the presented among iron oxide nanoparticles (NPs) aqueous colloids and bacteria. In other to find the forces among this interaction, we compare three types of surface modified NPs (exposing oxalate, arginine or cysteine residues), based on a simple synthesis and derivation procedure, that allows us to obtain very similar NPs (size and shape of the magnetic core). In this way, we assure that the main difference in the synthesized NPs are the oxalate or amino acid residue exposed, an ideal situation to compare their bacterial capture performance, and so too the interactions among them. Field emission scanning electron microscopy showed homogeneous distribution of particle sizes for all systems synthesized, close to 10 nm. Magnetization, zeta potential, Fourier transformed infrared spectrometry and other studies allow us further characterization. Capture experiments of Pseudomonas putida bacterial strain showed a high level of efficiency, independently of the amino acid used to wrap the NP, when compared with oxalate. We show that bacterial capture efficiency cannot be related mostly to the bacterial and NP superficial charge relationship (as determined by z potential), but instead capture can be correlated with hydrophobic and hydrophilic forces among them.

scholarly journals Biodiversity trends in Europe: development and testing of a species trend indicator for evaluating progress towards the 2010 target

2005 ◽  
Vol 360 (1454) ◽  
pp. 297-308 ◽  
Author(s):  
M de Heer ◽  
V Kapos ◽  
B.J.E ten Brink
Keyword(s):  
Population Declines ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
Depth Analysis ◽  
Species Population ◽  
2010 Target ◽  
Biogeographical Region ◽  
Using Data ◽  
High Level ◽  
Existing Data

This paper presents a trial of a species population trend indicator for evaluating progress towards the 2010 biodiversity target in Europe, using existing data. The indicator integrates trends on different species (groups), and can be aggregated across habitats and countries. Thus, the indicator can deliver both headline messages for high-level decision-making and detailed information for in-depth analysis, using data from different sources, collected with different methods. International non-governmental organizations mobilized data on over 2800 historical trends in national populations of birds, butterflies and mammals, for a total of 273 species. These were combined by habitat and biogeographical region to generate a pilot pan-European scale indicator. The trial indicator suggests a decline of species populations in nearly all habitats, the largest being in farmland, where species populations declined by an average of 23% between 1970 and 2000. The indicator is potentially useful for monitoring progress towards 2010 biodiversity targets, but constraints include: the limited sensitivity of the historical data, which leads to conservative estimates of species decline; a potential danger of ambiguity because increases in opportunistic species can mask the loss of other species; and failure to account for pre-1970 population declines. We recommend mobilizing additional existing data, particularly for plants and fishes, and elaborating further the criteria for compiling representative sets of species. For a frequent, reliable update of the indicator, sound, sensitive and harmonized biodiversity monitoring programmes are needed in all pan-European countries.

Analysis of Tyrrell Sea Deposits from the Vicinity of the Victor Diamond Mine: Comparison of Three North American Clay Deposits

2018 ◽  
Author(s):  
Jean Holloway
Keyword(s):  
Hydraulic Conductivity ◽  
Clay Fraction ◽  
Liquid Limit ◽  
Open Pit ◽  
Open Pit Mining ◽  
High Plasticity ◽  
Lake Agassiz ◽  
Clay Deposits ◽  
De Beers ◽  
Limestone Aquifers

he De Beers Victor Mine is an open pit diamond mine, and is located in the James Bay lowlands. The lowlands are characterized by extensive peatlands overlying Tyrell Sea sediments. One of the potential impacts of open pit mining, and the focus of the current work, is the potential for differential subsistence in the Tyrell Sea sediments owing to continuous groundwater withdrawal from the underlying limestone aquifers. To fully understand the potential effects of subsistence, a better understanding of the nature and properties of the Tyrell Sea sediments is needed. This will be achieved by analyzing various properties of samples collected from the Victor Diamond Mine, and comparing those properties with values from Lake Agassiz sediments and Bearpaw Shale. Properties such as hydraulic conductivity, grain size, plastic and liquid limit, and mineralogy will be compared. It is expected that the samples from the Victor Mine are a rock flour dominated by clay fraction, composed mostly of finely ground carbonates. The sediments are expected to have high plasticity, low hydraulic conductivity, and moisture content too low for that of true clay.

Not Quite What You Expected: The Curious Case of Brexit Scrutiny in the Czech Parliament

2019 ◽  
Author(s):  
Petr Kaniok ◽  
Monika Brusenbauch Meislova
Keyword(s):  
European Union ◽  
Party System ◽  
Party Politics ◽  
The European Union ◽  
Institutional Adjustment ◽  
Depth Analysis ◽  
The Government ◽  
High Level ◽  
The Eu

Abstract The aim of the article is to explore how the Czech bicameral parliament has reacted to the process of the United Kingdom's (UK's) withdrawal from the European Union (EU). Drawing upon insights from the theoretical expectations of parliamentary power, the inquiry researches the ways that Czech legislatures have developed in terms of engaging with and influencing the Brexit process. In this regard, the Czech case is exceptionally interesting and worth exploring, since the EU agenda has become a highly politicised issue within the Czech context. The significance of this inquiry has been further highlighted by the high level of party-based Euroscepticism typical of Czech politics as well as the frequent changes that the Czech party system has been undergoing in recent years. Throughout the in-depth analysis of parliamentary scrutiny activities—conceptualised as comprising four aspects: (i) the institutional adjustment; (ii) articulation of priorities; (iii) interactions with the government and (iv) parliamentary party politics—the article considers how these activities compare between both chambers of the Czech Parliament.

scholarly journals Development of the Availability Concept by Using Fuzzy Theory with AHP Correction, a Case Study: Bulldozers in the Open-Pit Lignite Mine

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4044 ◽  
Author(s):  
Stevan Djenadic ◽  
Dragan Ignjatovic ◽  
Milos Tanasijevic ◽  
Ugljesa Bugaric ◽  
Ivan Jankovic ◽  
...  
Keyword(s):  
Asset Management ◽  
Fuzzy Theory ◽  
Life Cycle Management ◽  
Open Pit ◽  
Engineering System ◽  
Analytic Hierarchy ◽  
Lignite Mine ◽  
It Support ◽  
High Level

Availability is one of the most used terms in maintainability engineering. This concept is used to denote: The quality of service of an engineering system, i.e., machines, weak points’ analysis, asset management, as well as making decisions in the process of life cycle management. Availability is an overall indicator and contains partial indicators that are oriented towards reliability, maintenance, and logistical support. Availability presents a variable value and changes in time and space. Usually, availability is shown as the coefficient of time use of the machine. This approach is not good enough because it does not go into the structure of the availability itself and requires a high level of IT support in system monitoring. In this sense, this paper will use the fuzzy theory and the corresponding analytic hierarchy process (AHP) multi-criteria analysis to present a conceptual and mathematical model for the assessment of availability based on expert judgment. The model will be shown in the case study (on the example) of bulldozers working in the open-pit lignite mine.

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