Simulation of nitrate transport in groundwater with a three-dimensional groundwater model run as a subroutine in an agroecosystem model

1991 ◽  
Vol 57 (3-4) ◽  
pp. 263-276 ◽  
Author(s):  
G. Wuttke ◽  
B. Thober ◽  
H. Lieth
Keyword(s):  
Three Dimensional ◽  
Nitrate Transport ◽  
Groundwater Model ◽  
Agroecosystem Model

scholarly journals Coupling saturated and unsaturated flow: comparing the iterative and the non-iterative approach

2021 ◽  
Author(s):  
Natascha Brandhorst ◽  
Daniel Erdal ◽  
Insa Neuweiler
Keyword(s):  
Unsaturated Zone ◽  
Unsaturated Flow ◽  
Three Dimensional ◽  
Lower Boundary ◽  
3D Models ◽  
Specific Yield ◽  
Iterative Approach ◽  
Groundwater Model ◽  
Iterative Coupling ◽  
Fully Integrated

Abstract. Fully integrated three dimensional (3D) physically based hydrologic models usually require many computational resources. For many applications, simplified models can be a cost effective alternative. 3D models of subsurface flow are often simplified by coupling a 2D groundwater model with multiple 1D models for the unsaturated zone. The crucial part of such models is the coupling between the two model compartments. In this work we compare two approaches for the coupling. One is iterative and the 1D unsaturated zone models go down to the impervious bottom of the aquifer and the other one is non-iterative and uses a moving lower boundary for the unsaturated zone. In this context we also propose a new way of treating the specific yield, which plays a crucial role in linking the unsaturated and the groundwater model. Both models are applied to three test cases with increasing complexity and analyzed in terms of accuracy and speed compared to fully integrated model runs. The non-iterative approach is faster while the iterative approach is more accurate and robust. Besides, for the iterative coupling method a calibration of the specific yield is not needed.

scholarly journals Evaluation of the potential impact of Grand Ethiopian Renaissance Dam and pumping scenarios on groundwater level in the Nile Delta aquifer

2017 ◽  
Vol 17 (5) ◽  
pp. 1356-1367 ◽  
Author(s):  
Asaad M. Armanuos ◽  
Mona G. Ibrahim ◽  
Wael Elham Mahmod ◽  
Abdelazim Negm ◽  
C. Yoshimura ◽  
...  
Keyword(s):  
Water Depth ◽  
Groundwater Level ◽  
Nile Delta ◽  
Three Dimensional ◽  
Actual Condition ◽  
Irrigation Canal ◽  
Groundwater Model ◽  
Worst Case ◽  
Study Results ◽  
Potential Impact

The main objective of this study is to evaluate the potential impact of Grand Ethiopian Renaissance Dam (GERD) and pumping scenarios on groundwater level by a three-dimensional groundwater model of the Nile Delta using MODFLOW software. The Nile Delta has highly intensive irrigation canal networks that share yearly about 35.5 km3 of water. In this study, an integrated three-dimensional groundwater model is built considering the actual condition of the irrigation canals and their recharges of the Nile Delta aquifer. The model was calibrated for estimating the vertical and hydraulic conductivity. The model was run for three scenarios: (1) reduction of water depth in canals, (2) increasing pumping discharge from the aquifer and (3) combination between the first and second scenarios. Results reveal that the effect of increasing the pumping discharge on groundwater level in the Nile Delta is more significant than decreasing the water depth of the canals network due to the fact of the existence of the upper clay layer which reduces the amount of water penetrating and reaching the groundwater in the aquifer. The last scenario presents the worst case as the average drawdown reached 1.26 m, 1.7 m and 1.35 m in the western, central and eastern parts of the Nile Delta respectively. The study results should be taken in account for studying the saltwater intrusion and climate change impacts on the Nile Delta region.

scholarly journals Groundwater flow modeling in an intermontane basin

2015 ◽  
Vol 49 (1) ◽  
pp. 7-15
Author(s):  
Dinesh Pathak
Keyword(s):  
Groundwater Flow ◽  
Three Dimensional ◽  
Unconsolidated Sediments ◽  
Groundwater Model ◽  
Basement Rocks ◽  
Deep Wells ◽  
Hydrogeological Study ◽  
Acceptable Model ◽  
Fence Diagram ◽  
Three Dimensional Configuration

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.

scholarly journals OpenMI: Open modelling interface

2007 ◽  
Vol 9 (3) ◽  
pp. 175-191 ◽  
Author(s):  
J. B. Gregersen ◽  
P. J. A. Gijsbers ◽  
S. J. P. Westen
Keyword(s):  
Three Dimensional ◽  
Integrated Modelling ◽  
Integrated Analysis ◽  
Software Components ◽  
Groundwater Model ◽  
One Dimensional ◽  
Time Basis ◽  
Model Components ◽  
River Models ◽  
Management Issues

Management issues in many sectors of society demand integrated analysis that can be supported by integrated modelling. Since all-inclusive modelling software is difficult to achieve, and possibly even undesirable, integrated modelling requires the linkage of individual models or model components that address specific domains. Emerging from the water sector, the OpenMI has been developed with the purpose of being the glue that can link together model components from various origins. The OpenMI provides a standardized interface to define, describe and transfer data on a time basis between software components that run simultaneously, thus supporting systems where feedback between the modelled processes is necessary in order to achieve physically sound results. The OpenMI allows the linking of models with different spatial and temporal representations: for example, linking river models and groundwater models, where the river model typically uses a one-dimensional grid and a short timestep and the groundwater model uses a two- or three-dimensional grid and a longer timestep. The OpenMI is designed to accommodate the easy migration of existing modelling systems, since their re-implementation may not be economically feasible due to the large investments that have been put into the development and testing of these systems.

scholarly journals Sustainable groundwater modeling using single- and multi-objective optimization algorithms

2016 ◽  
Vol 19 (1) ◽  
pp. 97-114 ◽  
Author(s):  
S. Sadeghi-Tabas ◽  
S. Z. Samadi ◽  
A. Akbarpour ◽  
M. Pourreza-Bilondi
Keyword(s):  
Groundwater Modeling ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Specific Yield ◽  
Groundwater Model ◽  
Absolute Deviation ◽  
Pumping Rate ◽  
Optimization Simulation ◽  
Pumping Rates ◽  
Management Alternatives

This study presents the first attempt to link the multi-algorithm genetically adaptive search method (AMALGAM) with a groundwater model to define pumping rates within a well distributed set of Pareto solutions. The pumping rates along with three minimization objectives, i.e. minimizing shortage affected by the failure to supply, modified shortage index and minimization of extent of drawdown within prespecified regions, were chosen to define an optimal solution for groundwater drawdown and subsidence. Hydraulic conductivity, specific yield parameters of a modular three-dimensional finite-difference (MODFLOW) groundwater model were first optimized using Cuckoo optimization algorithm (COA) by minimizing the sum of absolute deviation between the observed and simulated water table depths. These parameters were then applied in AMALGAM to optimize the pumping rate variables for an arid groundwater system in Iran. The Pareto parameter sets yielded satisfactory results when maximum and minimum drawdowns of the aquifer were defined in a range of −40 to +40 cm/year. Overall, ‘Modelling – Optimization – Simulation’ procedure was capable to compute a set of optimal solutions displayed on a Pareto front. The proposed optimal solution provides sustainable groundwater management alternatives to decision makers in arid region.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

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