Regional scale impact of tidal forcing on groundwater flow in unconfined coastal aquifers

2014 ◽  
Vol 517 ◽  
pp. 269-283 ◽  
Author(s):  
P.S. Pauw ◽  
G.H.P. Oude Essink ◽  
A. Leijnse ◽  
A. Vandenbohede ◽  
J. Groen ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Coastal Aquifers ◽  
Regional Scale ◽  
Tidal Forcing

scholarly journals Estimating the thickness of unconsolidated coastal aquifers along the global coastline

2018 ◽  
Vol 10 (3) ◽  
pp. 1591-1603 ◽  
Author(s):  
Daniel Zamrsky ◽  
Gualbert H. P. Oude Essink ◽  
Marc F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Coastal Aquifers ◽  
Regional Scale ◽  
Unconsolidated Sediments ◽  
Coastal Zones ◽  
Fresh Groundwater ◽  
Flow Models ◽  
Groundwater Flow Modelling ◽  
Groundwater Reserves ◽  
Geological Complexity

Abstract. Knowledge of aquifer thickness is crucial for setting up numerical groundwater flow models to support groundwater resource management and control. Fresh groundwater reserves in coastal aquifers are particularly under threat of salinization and depletion as a result of climate change, sea-level rise, and excessive groundwater withdrawal under urbanization. To correctly assess the possible impacts of these pressures we need better information about subsurface conditions in coastal zones. Here, we propose a method that combines available global datasets to estimate, along the global coastline, the aquifer thickness in areas formed by unconsolidated sediments. To validate our final estimation results, we collected both borehole and literature data. Additionally, we performed a numerical modelling study to evaluate the effects of varying aquifer thickness and geological complexity on simulated saltwater intrusion. The results show that our aquifer thickness estimates can indeed be used for regional-scale groundwater flow modelling but that for local assessments additional geological information should be included. The final dataset has been made publicly available (https://doi.pangaea.de/10.1594/PANGAEA.880771).

scholarly journals Estimating the thickness of unconsolidated coastal aquifers along the global coastline

2018 ◽  
Author(s):  
Daniel Zamrsky ◽  
Gualbert H. P. Oude Essink ◽  
Marc F. P. Bierkens
Keyword(s):  
Groundwater Flow ◽  
Coastal Aquifers ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Unconsolidated Sediments ◽  
Coastal Zones ◽  
Fresh Groundwater ◽  
Flow Models ◽  
Groundwater Flow Modelling ◽  
Groundwater Reserves

Abstract. Knowledge of the thickness of aquifers is crucial for setting up numerical groundwater flow models in support of the management and control of groundwater resources. Fresh groundwater reserves in coastal aquifers are particularly under threat of salinization and depletion as a result of climate change, sea-level rise, and excessive groundwater withdrawal under urbanization. To correctly assess the possible impacts of these pressures we must have better information about subsurface conditions in coastal zones. Here, we propose a method that combines available global datasets to estimate, along the global coastline, the thickness of aquifers formed by unconsolidated sediments. To validate our final estimation results, we collected both borehole and literature data. Additionally, we performed a numerical modelling study of the effects of varying aquifer thickness and geological complexity on simulated saltwater intrusion. The results show that our aquifer thickness estimates can indeed be used for regional scale groundwater flow modelling but that for local assessments additional geological information should be included. The final dataset can be downloaded via https://doi.pangaea.de/10.1594/PANGAEA.880771.

scholarly journals Groundwater contribution to river flows – using hydrograph separation, hydrological and hydrogeological models in a southern Quebec aquifer

2010 ◽  
Vol 7 (5) ◽  
pp. 7809-7838 ◽  
Author(s):  
M. Larocque ◽  
V. Fortin ◽  
M. C. Pharand ◽  
C. Rivard
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Regional Scale ◽  
Significant Proportion ◽  
Base Flow ◽  
Groundwater Flow Model ◽  
Hydrograph Separation ◽  
River Flows ◽  
Groundwater Contribution ◽  
Base Flows

Abstract. Groundwater contribution to river flows, generally called base flows, often accounts for a significant proportion of total flow rate, especially during the dry season. The objective of this work is to test simple approaches requiring limited data to understand groundwater contribution to river flows. The Noire river basin in southern Quebec is used as a case study. A lumped conceptual hydrological model (the MOHYSE model), a groundwater flow model (MODFLOW) and hydrograph separation are used to provide estimates of base flow for the study area. Results show that the methods are complementary. Hydrograph separation and the MOHYSE surface flow model provide similar annual estimates for the groundwater contribution to river flow, but monthly base flows can vary significantly between the two methods. Both methods have the advantage of being easily implemented. However, the distinction between aquifer contribution and shallow subsurface contribution to base flow can only be made with a groundwater flow model. The aquifer renewal rate estimated with the MODFLOW model for the Noire River is 30% of the recharge estimated from base flow values. This is a significantly difference which can be crucial for regional-scale water management.

scholarly journals Characterization of Surface Evidence of Groundwater Flow Systems in Continental Mexico

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2459
Author(s):  
Alessia Kachadourian-Marras ◽  
Margarita M. Alconada-Magliano ◽  
José Joel Carrillo-Rivera ◽  
Edgar Mendoza ◽  
Felipe Herrerías-Azcue ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Water Cycle ◽  
Regional Scale ◽  
Ground Surface ◽  
The Public ◽  
Groundwater Flow Systems ◽  
Human Needs ◽  
Flow Systems ◽  
Vegetation And Climate

The dynamics of the underground part of the water cycle greatly influence the features and characteristics of the Earth’s surface. Using Tóth’s theory of groundwater flow systems, surface indicators in Mexico were analyzed to understand the systemic connection between groundwater and the geological framework, relief, soil, water bodies, vegetation, and climate. Recharge and discharge zones of regional groundwater flow systems were identified from evidence on the ground surface. A systematic hydrogeological analysis was made of regional surface indicators, published in official, freely accessible cartographic information at scales of 1:250,000 and 1:1,000,000. From this analysis, six maps of Mexico were generated, titled “Permanent water on the surface”, “Groundwater depth”, “Hydrogeological association of soils”, “Hydrogeological association of vegetation and land use”, “Hydrogeological association of topoforms”, and “Superficial evidence of the presence of groundwater flow systems”. Mexico’s hydrogeological features were produced. The results show that 30% of Mexico is considered to be discharge zones of groundwater flow systems (regional, intermediate, and recharge). Natural recharge processes occur naturally in 57% of the country. This work is the first holistic analysis of groundwater in Mexico carried out at a national–regional scale using only the official information available to the public. These results can be used as the basis for more detailed studies on groundwater and its interaction with the environment, as well as for the development of integrative planning tools to ensure the sustainability of ecosystems and satisfy human needs.

scholarly journals Editorial of Special Issue “Advances in Groundwater Flow and Solute Transport: Pushing the Hidden Boundary”

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 457
Author(s):  
Hongbin Zhan ◽  
Quanrong Wang ◽  
Zhang Wen
Keyword(s):  
Numerical Methods ◽  
Groundwater Flow ◽  
Solute Transport ◽  
Vadose Zone ◽  
Regional Scale ◽  
Chemical Transport ◽  
Low Permeability ◽  
Special Issue ◽  
Flow And Transport ◽  
Wide Range

The theme of this special issue is to explore the new territories beyond conventional subsurface flow and transport theories. We have selected 12 articles in this special issue and these articles cover a wide range of problems including (1) Non-Fickian chemical transport in various environments; (2) Non-Darcian flow; (3) Flow and transport in low-permeability media; (4) Vadose zone process; (5) Regional scale groundwater flow and groundwater-surface interaction; (6) Innovative numerical methods. The major contributions of these papers are summarized in this editorial.

scholarly journals Influence of aquifer and streambed heterogeneity on the distribution of groundwater discharge

2009 ◽  
Vol 13 (1) ◽  
pp. 69-77 ◽  
Author(s):  
E. Kalbus ◽  
C. Schmidt ◽  
J. W. Molson ◽  
F. Reinstorf ◽  
M. Schirmer
Keyword(s):  
Groundwater Flow ◽  
Transport Model ◽  
Regional Scale ◽  
Base Case ◽  
Case Scenario ◽  
Base Case Scenario ◽  
Heterogeneous Distribution ◽  
Heterogeneous Aquifer ◽  
The Impact ◽  
Low K

Abstract. The spatial distribution of groundwater fluxes through a streambed can be highly variable, most often resulting from a heterogeneous distribution of aquifer and streambed permeabilities along the flow pathways. Using a groundwater flow and heat transport model, we defined four scenarios of aquifer and streambed permeability distributions to simulate and assess the impact of subsurface heterogeneity on the distribution of groundwater fluxes through the streambed: (a) a homogeneous low-K streambed within a heterogeneous aquifer; (b) a heterogeneous streambed within a homogeneous aquifer; (c) a well connected heterogeneous low-K streambed within a heterogeneous aquifer; and (d) a poorly connected heterogeneous low-K streambed within a heterogeneous aquifer. The simulation results were compared with a base case scenario, in which the streambed had the same properties as the aquifer, and with observed data. The results indicated that the aquifer has a stronger influence on the distribution of groundwater fluxes through the streambed than the streambed itself. However, a homogeneous low-K streambed, a case often implemented in regional-scale groundwater flow models, resulted in a strong homogenization of fluxes, which may have important implications for the estimation of peak mass flows. The flux distributions simulated with heterogeneous low-K streambeds were similar to the flux distributions of the base case scenario, despite the lower permeability. The representation of heterogeneous distributions of aquifer and streambed properties in the model has been proven to be beneficial for the accuracy of flow simulations.

Including hydrologic signatures in the calibration of a groundwater-surface water model to improve representation of artificial drain

2020 ◽  
Author(s):  
Simon Stisen ◽  
Raphael Schneider ◽  
Anker Lajer Højberg
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Large Scale ◽  
Agricultural Land ◽  
Water Cycle ◽  
Regional Scale ◽  
Drainage System ◽  
Water Model ◽  
Hydrological Models ◽  
Drain Flow

<p>About half of the Danish agricultural land is artificially drained to make land arable and increase crop yield. Those artificial drains, mostly in the form on tile drains, have a significant effect on the groundwater flow patterns and the whole water cycle. Consequently, the drainage system must also be represented in hydrological models that are used to understand and simulate, for example, recharge patterns, groundwater flow paths, or the transport and retention of nutrients. However, representation of drain in regional- and large-scale hydrological models is challenging due to i) issues with scale, ii) a lack of data on the distribution of the drain network, and iii) a lack of direct observations of drain flow. This calls for more indirect methods to inform such models.</p><p>We assume that drain flow leaves a signal in certain hydrograph signatures, as it impacts the generation of streamflow. Based on a dataset of observed discharge covering all of Denmark, and simulation results from regional-scale hydrological models, we use machine learning regressors to shed light on possible correlations between hydrograph signatures and artificial drainage. Building up on this step, we run a series of calibration exercises on a hydrological model of the agriculturally dominated Norsminde catchment, Denmark (~100 km<sup>2</sup>). The model is set up in the DHI MIKE SHE software, as distributed coupled groundwater-surface water models with a grid size of 100 m. The different calibration exercises differed in the objective functions used: either we only use conventional stream flow metrics (KGE), or also include hydrograph signatures that showed sensitive towards drain flow in our regression analysis. We then evaluate the results from the different calibration exercises, in terms of how well the model reproduces directly observed drain flow, and spatial drainage patterns.</p><p>Despite including hydrologic signatures in the calibration process, the representation of drain flow in large-scale models remains challenging. Eventually, the insight gained from this and similar studies will be incorporated in the National Water Resources Model for Denmark, to help improving national targeted regulation of nitrate application through fertilizers.</p>

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