A basin-scale groundwater flow model in the Columbia Plateau (Pacific Northwest, USA); insights for management of fractured aquifer-types

2020 ◽  
Author(s):  
Giacomo Medici
Keyword(s):  
Stable Isotope ◽  
Groundwater Flow ◽  
Particle Tracking ◽  
Flow Model ◽  
Columbia River ◽  
Groundwater Flow Model ◽  
Fractured Aquifer ◽  
Isotope Data ◽  
Columbia River Basalt ◽  
Stable Isotope Data

<p>Mechanical discontinuities control groundwater flow in fractured aquifers. Bedding plane and sub-vertical discontinuities create fracture networks geometrically organized both horizontally and vertically in areas un-affected by compressional tectonic forces. In this structural setting, we use the Columbia River Basalt aquifer in the Palouse to show how the combination of previous acquired stable isotope data and geological, groundwater, and particle tracking modeling better describes groundwater flow in three dimensions. We present a steady-state flow model simulating backward particle traces from abstraction wells to the recharge boundaries. Backwards particle analysis coupled with the <sup>14</sup>C isotope vertical concentration distribution shows how the aquifer system is characterized by two separate zones. A shallow (<120 mBGL) zone of freshwater circulation is characterized by higher <sup>14</sup>C concentrations and low particle travel times with respect to the deeper (>120 mBGL) aquifer zone. Here, penetration of particles is partially impeded by the low vertical hydraulic conductivity of the volcano-sedimentary layers and recharge preferentially occurs in correspondence of discontinuities related to a geological unconformity. Hence, the outputs of a particle tracking analysis fits stable isotope data either validating a 3D groundwater flow model or aiding detail to conceptualization of a fractured aquifer.</p><p>The Columbia River Basalt aquifer is also horizontally anisotropic due to sub-vertical tectonic fractures which are related to gentle folding and faulting. This horizontal anisotropy significantly influences particle tracking analysis in the basin up to 120 mBGL. Well-head protection areas are defined globally by backward particle tracking analyses at shallow depths. Thus, as a consequence of this research we envisage introduction of horizontal anisotropies in groundwater flow models for definition of well capture zones.</p>

scholarly journals Noble gases as natural tracers of water circulation in the Paris Basin: 2. Calibration of a groundwater flow model using noble gas isotope data

1998 ◽  
Vol 34 (10) ◽  
pp. 2467-2483 ◽  
Author(s):  
Maria Clara Castro ◽  
Patrick Goblet ◽  
Emmanuel Ledoux ◽  
Sophie Violette ◽  
Ghislain de Marsily
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Noble Gases ◽  
Noble Gas ◽  
Water Circulation ◽  
Groundwater Flow Model ◽  
Paris Basin ◽  
Natural Tracers ◽  
Isotope Data ◽  
Noble Gas Isotope

scholarly journals Conceptual and Mathematical Modeling of a Coastal Aquifer in Eastern Delta of R. Nestos (N. Greece)

Hydrology ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Ioannis Gkiougkis ◽  
Christos Pouliaris ◽  
Fotios-Konstantinos Pliakas ◽  
Ioannis Diamantis ◽  
Andreas Kallioras
Keyword(s):  
Mathematical Modeling ◽  
Groundwater Flow ◽  
Coastal Aquifer ◽  
Flow Model ◽  
Meteorological Data ◽  
Field Measurements ◽  
Groundwater Flow Model ◽  
Aquifer System ◽  
Geophysical Surveys ◽  
The Mathematical Model

In this paper, the development of the conceptual and groundwater flow model for the coastal aquifer system of the alluvial plain of River Nestos (N. Greece), that suffers from seawater intrusion due to over-pumping for irrigation, is analyzed. The study area is a typical semi-arid hydrogeologic environment, composed of a multi-layer granular aquifers that covers the eastern coastal delta system of R. Nestos. This study demonstrates the results of a series of field measurements (such as geophysical surveys, hydrochemical and isotopical measurements, hydro-meteorological data, land use, irrigation schemes) that were conducted during the period 2009 to 2014. The synthesis of the above resulted in the development of the conceptual model for this aquifer system, that formed the basis for the application of the mathematical model for simulating groundwater flow. The mathematical modeling was achieved using the finite difference method after the application of the USGS code MODFLOW-2005.

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.

scholarly journals Inverse Parametrization of a Regional Groundwater Flow Model with the Aid of Modelling and GIS: Test and Application of Different Approaches

2018 ◽  
Vol 7 (1) ◽  
pp. 22 ◽  
Author(s):  
Muhammad Usman ◽  
Thomas Reimann ◽  
Rudolf Liedl ◽  
Azhar Abbas ◽  
Christopher Conrad ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Groundwater Flow Model ◽  
Regional Groundwater
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