scholarly journals Simulation of groundwater flow and the interaction of groundwater and surface water in the Willamette Basin and Central Willamette subbasin, Oregon

Author(s):  
Nora B. Herrera ◽  
Erick R. Burns ◽  
Terrence D. Conlon
2021 ◽  
Author(s):  
Goedele Verreydt ◽  
Niels Van Putte ◽  
Timothy De Kleyn ◽  
Joris Cool ◽  
Bino Maiheu

<p>Groundwater dynamics play a crucial role in the spreading of a soil and groundwater contamination. However, there is still a big gap in the understanding of the groundwater flow dynamics. Heterogeneities and dynamics are often underestimated and therefore not taken into account. They are of crucial input for successful management and remediation measures. The bulk of the mass of mass often is transported through only a small layer or section within the aquifer and is in cases of seepage into surface water very dependent to rainfall and occurring tidal effects.</p><p> </p><p>This study contains the use of novel real-time iFLUX sensors to map the groundwater flow dynamics over time. The sensors provide real-time data on groundwater flow rate and flow direction. The sensor probes consist of multiple bidirectional flow sensors that are superimposed. The probes can be installed directly in the subsoil, riverbed or monitoring well. The measurement setup is unique as it can perform measurements every second, ideal to map rapid changing flow conditions. The measurement range is between 0,5 and 500 cm per day.</p><p> </p><p>We will present the measurement principles and technical aspects of the sensor, together with two case studies.</p><p> </p><p>The first case study comprises the installation of iFLUX sensors in 4 different monitoring wells in a chlorinated solvent plume to map on the one hand the flow patterns in the plume, and on the other hand the flow dynamics that are influenced by the nearby popular trees. The foreseen remediation concept here is phytoremediation. The sensors were installed for a period of in total 4 weeks. Measurement frequency was 5 minutes. The flow profiles and time series will be presented together with the determined mass fluxes.</p><p> </p><p>A second case study was performed on behalf of the remediation of a canal riverbed. Due to industrial production of tar and carbon black in the past, the soil and groundwater next to the small canal ‘De Lieve’ in Ghent, Belgium, got contaminated with aliphatic and (poly)aromatic hydrocarbons. The groundwater contaminants migrate to the canal, impact the surface water quality and cause an ecological risk. The seepage flow and mass fluxes of contaminants into the surface water were measured with the novel iFLUX streambed sensors, installed directly in the river sediment. A site conceptual model was drawn and dimensioned based on the sensor data. The remediation concept to tackle the inflowing pollution: a hydraulic conductive reactive mat on the riverbed that makes use of the natural draining function of the waterbody, the adsorption capacity of a natural or secondary adsorbent and a future habitat for micro-organisms that biodegrade contaminants. The reactive mats were successfully installed and based on the mass flux calculations a lifespan of at least 10 years is expected for the adsorption material.  </p>


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Mohammad Ainul Labib ◽  
Agung Suprianto ◽  
Devi Prasetyo ◽  
Aan Seftian Hardianto ◽  
Alfi Sahrina ◽  
...  

Bagus-Jebrot Cave is located in Donomulyo District, Malang Regency which is in the Wonosari Formation which was formed in the Middle Miocene and Late Miocene. The purpose of this study is related to the developmental control that affects the cave passageways. The approach used is a geomorphological approach by conducting field measurements and documentation. The analysis used is frequency analysis and cross-section of the passage. Bagus-Jebrot Cave is a type of Epigenic Cave which is formed from surface water flowing into doline/sinkhole. It can be seen from the planview map that has a curvilinear passage pattern. The existence of groundwater flow also forms a physiographic cave passage with ellipse passage formation, asymmetrical ellipse, potholes, callops, solution notches, cups, solution pockets. Besides underground water flow, the development of the Bagus-Jebrot Cave aisle is related to the process of structural lifting and control. The lifting process is marked by the formation of 4 levels of the cave passage. While the formation of the canyon, joint passage, rectangular passage and keyhole is the result of structural control


Author(s):  
Kent Werner ◽  
Emma Bosson ◽  
Sten Berglund

The safety assessments of potential geological repositories for spent nuclear fuel in Sweden are supported by modelling of groundwater flow in rock, to predict locations (exit points) where radionuclides from the deep repository may enter land, surface waters and associated ecosystems above the rock. This modelling includes detailed rock descriptions, but simplifies the upper part of the flow domain, including representations of meteorological processes and interactions with hydrological objects at the surface. Using the Laxemar candidate site as example, this paper investigates some potentially important consequences of these simplifications. Specifically, it compares particle tracking results obtained by a deep-rock groundwater flow model (CONNECTFLOW) and by MIKE SHE-MIKE 11, which contains detailed descriptions of near-surface/surface water flow. Overall, the models predict similar exit point patterns, occurring as clusters along streams in valleys, at a lake, and in sea bays. However, on a detailed level there are some prediction differences, which may be of importance for biosphere-focused safety assessments. CONNECTFLOW essentially predicts flow paths through the repository that follow fractures and deformation zones, outcropping in valleys. In comparison, MIKE SHE-MIKE 11 provides more detailed information on near-surface water flow paths, including the associated exit points and inputs to assessments of radionuclide retention.


2020 ◽  
Author(s):  
Yosuke Miura ◽  
Kei Yoshimura

<p>  Groundwater is one of the important water resources in the world and Groundwater flow is linked with surface water strongly. Many studies on groundwater are conducted in a local scale or focused on affect-ing surface water in a global scale. In current Earth System Model, fixed and constant one-dimensional vertical grid is used in unsaturated zone. In real world, the thickness of unsatu-rated zone depends on the climate and it is considered that there are limitations of runoff process expression especially in humid mountainous area. In this study, we developed three-dimensional groundwater flow model as ESM which can represent the variably saturated flow and groundwa-ter storativity. Since, this model is eventually coupled with Land Surface Model, it is possible to track the underground water flow using boundary conditions of recharge and surface water level.</p><p>  We verified accuracy of the code using one & two-dimensional infiltration problem, three-dimensional groundwater pumping problem, and hillslope problem. Our model was com-pared with other researchers results, experimental data, analytical solutions. In consequence, our model was able to get accurate results. Subsequently, we conducted validation in Central valley, California, USA. The reason of chose this region is that this region is a semi-arid region, ground-water is used for irrigation and well pumping data is accessible. Over the world, groundwater use is more important in arid or semi-arid region than in humid area, and also highly utilized as agri-cultural water. Central valley has representativeness of groundwater use. In addition, the famous groundwater model, MODFLOW, was used to evaluate water resource management in this region. As well as MODFLOW, we calibrated hydraulic conductivity with 24 observation sites during 1961 - 2003 to validate. 156 observation points excluded 24 calibration points were used as vali-dation in same period. In the near future, we will confirm the difference between one-dimension and three dimensions setting of the unsaturated zone with respect to runoff process.</p>


2020 ◽  
Author(s):  
Simon Stisen ◽  
Raphael Schneider ◽  
Anker Lajer Højberg

<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>


Author(s):  
Waldilene Correa ◽  
Sueli Pereira ◽  
Joaquim Ernesto Bernardes ◽  
Paulo Ricardo Pereira

Groundwater-Surface water interactions in alluvial plains facing morphological features are the subject of the study. Considered transitions zones, alluvial plains have different morphological features interfering with groundwater flow and hydrochemistry. The alluvial plain of Mogi Guaçu river (southeastern Brazil) presented topography-controlled groundwater flow, nevertheless, natural levees, wet fields, oxbow lakes, and abandoned meanders can control local flow and interfere in discharges points of the main river. Two sampling water campaigns were done in the dry and wet season for physicochemical and natural isotopes analysis, collecting in total 44 groundwaters samples from monitoring wells and eight water samples from the river, creek, and lake. The groundwaters in wet fields and terraces, and surface waters from creek and lake presented low mineralization (EC from 8 to 37 μS.cm), pH acidic (4.98 to 5.8), and essentially Ca and Na-HCO composition. River waters samples presented pH between 5.92 e 7.69 (acidic in the rainy season and basic in the dry season), and EC from 24.2 and 181.1 μS/cm (lower values in the wet season), Na-HCO and Na-HCO-SO (dry season) and Ca-HCO and Na-HCO (rainy season) compositions. In dry season groundwaters composition showed evolution from sodium mixed (SO – HCO) to bicarbonate waters and higher mineralization; in wet season waters varied from Ca to Na-HCO composition and low mineralization, denoting dilution due to rainwater infiltration. Closer to the river margins, in abandoned meanders and oxbows, the groundwaters have increased values of EC and major ions indicating GW-SW mixtures, and effluent-influent changes (descendent and ascendent flux) in wet and dry seasons, respectively. Natural isotopes in groundwaters imply meteoric origin, without evaporation during recharge and high d-excess can be influenced by continental air masses and Amazonia Basin low-level jet. Shallow water table, permeable silty-sand material of vadose zone, flat terrain, and pristine conditions can contribute to direct infiltration of rainwaters, recharging the shallow aquifer.


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