Groundwater flow modeling in an intermontane basin

Groundwater model has become a commonly used tool to perform various tasks. Geological, hydrogeological and geophysical data is required for constructing 3D hydrogeological framework models. Most of the time, it is realised that there is lack of sufficient data to build a groundwater model. The present work has been achieved after systematic data collection and hydrogeological study of Nara Basin, west Japan. Groundwater has been widely exploited for drinking water supply as well as for recreation purpose as Thermal Springs in the Nara Basin. There are hundreds of wells drilled in unconsolidated sediments and some tens of deep wells encountering the fractured basement. When water is exploited from a groundwater basin, it is necessary to understand properly the groundwater flow in different aquifer zones in the basin. Hydrostratigraphic units in the unconsolidated sediments overlying the basement rocks were established by using the borehole log data. In order to have understanding of the three dimensional configuration of these units, fence diagram was constructed. The geological and hydrogeological information were used to develop a conceptual model which was further calibrated and an acceptable model was obtained. The model was validated by comparing the observed and simulated heads and discharge.

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Program Developments For Modeling Groundwater Flow In Three-Dimensional Heterogeneous Aquifers With MODFLOW And MODFLOWP

10.21236/ada588758 ◽

1998 ◽

Author(s):

Kangle Huang ◽

Tom Clemo ◽

Warren Barrash

Keyword(s):

Groundwater Flow ◽

Three Dimensional ◽

Heterogeneous Aquifers

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Three-dimensional hydrostratigraphy and groundwater flow models in complex Quaternary deposits and weathered/fractured bedrock: evaluating increasing model complexity

Hydrogeology Journal ◽

10.1007/s10040-020-02299-4 ◽

2021 ◽

Author(s):

Susanne Charlotta Åberg ◽

Annika Katarina Åberg ◽

Kirsti Korkka-Niemi

Keyword(s):

Groundwater Flow ◽

Three Dimensional ◽

Model Complexity ◽

Quaternary Sediments ◽

Fractured Bedrock ◽

Flow Models ◽

Flow Modelling ◽

Crystalline Bedrock ◽

Discharge Patterns ◽

Geological Units

AbstractGreater complexity in three-dimensional (3D) model structures yields more plausible groundwater recharge/discharge patterns, especially in groundwater/surface-water interactions. The construction of a 3D hydrostratigraphic model prior to flow modelling is beneficial when the hydraulic conductivity of geological units varies considerably. A workflow for 3D hydrostratigraphic modelling with Leapfrog Geo and flow modelling with MODFLOW-NWT was developed. It was used to evaluate how the modelling results for groundwater flow and recharge/discharge patterns differ when using simple or more complex hydrostratigraphic models. The workflow was applied to a study site consisting of complex Quaternary sediments underlain by fractured and weathered crystalline bedrock. Increasing the hydrostratigraphic detail appeared to improve the fit between the observed and simulated water table, and created more plausible groundwater flow patterns. Interlayered zones of low and high conductivity disperse the recharge/discharge patterns, increasing the vertical flow component. Groundwater flow was predominantly horizontal in models in which Quaternary sediments and bedrock were simplified as one layer per unit. It appears to be important to define the interlayered low-conductivity units, which can limit groundwater infiltration and also affect groundwater discharge patterns. Explicit modelling with Leapfrog Geo was found to be effective but time-consuming in the generation of scattered and thin-layered strata.

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Nonlinear effects of locally heterogeneous hydraulic conductivity fields on regional stream–aquifer exchanges

Hydrology and Earth System Sciences ◽

10.5194/hess-19-4531-2015 ◽

2015 ◽

Vol 19 (11) ◽

pp. 4531-4545 ◽

Cited By ~ 2

Author(s):

J. Zhu ◽

C. L. Winter ◽

Z. Wang

Keyword(s):

Groundwater Flow ◽

Effective Conductivity ◽

Model Simulation ◽

Three Dimensional ◽

Small Scale ◽

Heihe River ◽

Effective Parameters ◽

Aquifer Systems ◽

Basin Scale ◽

Local Grid

Abstract. Computational experiments are performed to evaluate the effects of locally heterogeneous conductivity fields on regional exchanges of water between stream and aquifer systems in the Middle Heihe River basin (MHRB) of northwestern China. The effects are found to be nonlinear in the sense that simulated discharges from aquifers to streams are systematically lower than discharges produced by a base model parameterized with relatively coarse effective conductivity. A similar, but weaker, effect is observed for stream leakage. The study is organized around three hypotheses: (H1) small-scale spatial variations of conductivity significantly affect regional exchanges of water between streams and aquifers in river basins, (H2) aggregating small-scale heterogeneities into regional effective parameters systematically biases estimates of stream–aquifer exchanges, and (H3) the biases result from slow paths in groundwater flow that emerge due to small-scale heterogeneities. The hypotheses are evaluated by comparing stream–aquifer fluxes produced by the base model to fluxes simulated using realizations of the MHRB characterized by local (grid-scale) heterogeneity. Levels of local heterogeneity are manipulated as control variables by adjusting coefficients of variation. All models are implemented using the MODFLOW (Modular Three-dimensional Finite-difference Groundwater Flow Model) simulation environment, and the PEST (parameter estimation) tool is used to calibrate effective conductivities defined over 16 zones within the MHRB. The effective parameters are also used as expected values to develop lognormally distributed conductivity (K) fields on local grid scales. Stream–aquifer exchanges are simulated with K fields at both scales and then compared. Results show that the effects of small-scale heterogeneities significantly influence exchanges with simulations based on local-scale heterogeneities always producing discharges that are less than those produced by the base model. Although aquifer heterogeneities are uncorrelated at local scales, they appear to induce coherent slow paths in groundwater fluxes that in turn reduce aquifer–stream exchanges. Since surface water–groundwater exchanges are critical hydrologic processes in basin-scale water budgets, these results also have implications for water resources management.

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Three-dimensional semi-analytical solution to groundwater flow in confined and unconfined wedge-shaped aquifers

Advances in Water Resources ◽

10.1016/j.advwatres.2009.03.004 ◽

2009 ◽

Vol 32 (6) ◽

pp. 925-935 ◽

Cited By ~ 12

Author(s):

Mohammad Mahdi Sedghi ◽

Nozar Samani ◽

Brent Sleep

Keyword(s):

Analytical Solution ◽

Groundwater Flow ◽

Three Dimensional

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The effect of hydrogeological and hydrochemical dynamics on landslide triggering in the central highlands of Ethiopia

Hydrogeology Journal ◽

10.1007/s10040-020-02288-7 ◽

2021 ◽

Vol 29 (3) ◽

pp. 1239-1260

Author(s):

Tesfay Kiros Mebrahtu ◽

Andre Banning ◽

Ermias Hagos Girmay ◽

Stefan Wohnlich

Keyword(s):

Hydrostatic Pressure ◽

Groundwater Flow ◽

Volcanic Rocks ◽

Chemical Characterization ◽

Unconsolidated Sediments ◽

Ethiopian Rift ◽

Main Ethiopian Rift ◽

Groundwater Level Fluctuations ◽

Landslide Mass ◽

Landslide Triggering

AbstractThe volcanic terrain at the western margin of the Main Ethiopian Rift in the Debre Sina area is known for its slope stability problems. This report describes research on the effects of the hydrogeological and hydrochemical dynamics on landslide triggering by using converging evidence from geological, geomorphological, geophysical, hydrogeochemical and isotopic investigations. The chemical characterization indicates that shallow to intermediate aquifers cause groundwater flow into the landslide mass, influencing long-term groundwater-level fluctuations underneath the landslide and, as a consequence, its stability. The low content of total dissolved solids and the bicarbonate types (Ca–Mg–HCO3 and Ca–HCO3) of the groundwater, and the dominantly depleted isotopic signature, indicate a fast groundwater flow regime that receives a high amount of precipitation. The main causes of the landslide are the steep slope topography and the pressure formed during precipitation, which leads to an increased weight of the loose and weathered materials. The geophysical data indicate that the area is covered by unconsolidated sediments and highly decomposed and weak volcanic rocks, which are susceptible to sliding when they get moist. The heterogeneity of the geological materials and the presence of impermeable layers embodied within the highly permeable volcanic rocks can result in the build-up of hydrostatic pressure at their interface, which can trigger landslides. Intense fracturing in the tilted basalt and ignimbrite beds can also accelerate infiltration of water, resulting to the build-up of high hydrostatic pressure causing low effective normal stress in the rock mass, giving rise to landslides.

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Improvement on Permeability of Cyclic Peptide/Peptidomimetic: Backbone N-Methylation as A Useful Tool

Marine Drugs ◽

10.3390/md19060311 ◽

2021 ◽

Vol 19 (6) ◽

pp. 311

Author(s):

Yang Li ◽

Wang Li ◽

Zhengshuang Xu

Keyword(s):

Cyclic Peptides ◽

Cyclic Peptide ◽

Three Dimensional ◽

Conformational Space ◽

Cell Permeability ◽

Relative Importance ◽

Intrinsic Properties ◽

Surface Areas ◽

Synthetic Methodologies ◽

Three Dimensional Configuration

Peptides have a three-dimensional configuration that can adopt particular conformations for binding to proteins, which are well suited to interact with larger contact surface areas on target proteins. However, low cell permeability is a major challenge in the development of peptide-related drugs. In recent years, backbone N-methylation has been a useful tool for manipulating the permeability of cyclic peptides/peptidomimetics. Backbone N-methylation permits the adjustment of molecule’s conformational space. Several pathways are involved in the drug absorption pathway; the relative importance of each N-methylation to total permeation is likely to differ with intrinsic properties of cyclic peptide/peptidomimetic. Recent studies on the permeability of cyclic peptides/peptidomimetics using the backbone N-methylation strategy and synthetic methodologies will be presented in this review.

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Analyses of groundwater flow and plant evapotranspiration in a vegetated soil slope

Canadian Geotechnical Journal ◽

10.1139/cgj-2013-0148 ◽

2013 ◽

Vol 50 (12) ◽

pp. 1204-1218 ◽

Cited By ~ 43

Author(s):

A.K. Leung ◽

C.W.W. Ng

Keyword(s):

Groundwater Flow ◽

Pore Water Pressure ◽

Water Pressure ◽

Three Dimensional ◽

Root Water Uptake ◽

Dry Season ◽

Climatic Data ◽

Wet Season ◽

Soil Slopes ◽

Transient Seepage

Understanding seasonal hydrogeological responses of vegetated soil slopes is vital to slope stability because pore-water pressure (PWP) varies from positive values upon rainfall in wet seasons to negative values upon plant evapotranspiration (ET) in dry seasons. There are, however, few case histories that report seasonal performance of vegetated soil slopes. In this study, a vegetated slope situated in Hong Kong was instrumented to analyse (i) groundwater flow during rainfall in the wet season and (ii) effects of plant ET on PWP in the dry season. Two- and three-dimensional anisotropic transient seepage analyses are conducted to identify groundwater flow mechanism(s) during a heavy rainstorm. Through water and energy balance calculations, measured plant-induced suction is interpreted with plant characteristic and climatic data. During the rainstorm, substantial recharge of the groundwater table was recorded, likely due to preferential water flow along relict joints and three-dimensional cross-slope groundwater flow. During the dry season, the peak suction induced by plant ET is up to 200 kPa and the depth of influence is shallower than 200% of the root depth. For the range of suctions monitored, root-water uptake is revealed to have been restricted by suction not very significantly and was driven mainly by the climatic variation.

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

Gornyi Zhurnal ◽

10.17580/gzh.2021.05.12 ◽

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.

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