Author
George B. Matanga
Bio: George B. Matanga is an academic researcher. The author has contributed to research in topics: Groundwater flow & Hydraulic head. The author has an hindex of 4, co-authored 5 publications receiving 157 citations.
Topics: Groundwater flow, Hydraulic head, Irrigation, Crop yield, Potential flow
Papers
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TL;DR: In this paper, an area-allocation model for corn, grain sorghum and pinto beans is proposed to maximize gross margin from yields of crops under consideration subject to total water supply, maximum amount of water that can be delivered for irrigation purposes on any date of irrigation, and irrigation labor.
Abstract: Irrigation programs, specified in terms of dates and depths of irrigation, are developed for corn, grain sorghum and pinto beans. The information contained in the irrigation programs for each crop is applied in an area-allocation model to determine a cropping pattern for the three crops. The area-allocation model is a linear optimization model which maximizes gross margin from yields of crops under consideration subject to total water supply, maximum amount of water that can be delivered for irrigation purposes on any date of irrigation, and irrigation labor. The land area to be allocated to each crop for planting is the decision variable. Results from the area-allocation model include cropping pattern, gross margin, total irrigation depth on each date of irrigation, total irrigation labor, and crop yield. Sensitivity analysis is performed to study the effect of changes in crop prices on the optimal results.
65 citations
TL;DR: For a finite or infinite planning horizon, an interseasonal model is employed to determine an irrigation policy in terms of leaching and seasonal irrigation depths in this paper, which employs stochastic dynamic programming and simulation to maximize gross margin over the planning horizon.
Abstract: For a finite or infinite planning horizon, an interseasonal model is employed to determine an irrigation policy in terms of leaching and seasonal irrigation depths. The interseasonal model employs stochastic dynamic programming and simulation to maximize gross margin over the planning horizon. Solutions to the model are obtained by value iteration and policy iteration methods for a finite and infinite planning horizons, respectively, with researched crop characteristics and measured climatic parameters from Davis, California. Salinity in the root zone of plants is defined as the state variable. A stage is a year commencing at the end of the rainy season. Seasonal rainfall is treated as a stochastic variable. The information provided by the interseasonal model is used in an area-allocation model that allocates acreage available for planting among the crops for unlimited and limited water supplies.
49 citations
TL;DR: In this article, two partial differential equations of stream functions χ and λ in three-dimensional groundwater flow are developed, which are valid for steady state groundwater flow under the Borden landfill in Ontario, Canada.
Abstract: Development of the partial differential equation of stream function ψ in two-dimensional groundwater flow is based on the assumption that the curl of hydraulic gradient vector (∇×∇ϕ) is equal to zero. The equation of ψ is expressed in terms of hydraulic conductivity. This equation is valid for steady state groundwater flow only. In this paper, two partial differential equations of stream functions χ and λ in three-dimensional groundwater flow are developed. In development of these equations, it is assumed that the curl of pseudopotential gradient (∇×∇β) is equal to zero. Pseudopotential gradient is the hydraulic gradient in the direction of flow. The equations of χ and λ are expressed in terms of pseudopotential conductivity. Pseudopotential conductivity is the hydraulic conductivity in the direction of flow. It is a scalar function and can be defined in terms of hydraulic gradient and hydraulic conductivity. Therefore besides being valid for steady state flow, the equations of χ and λ can be applied to evaluate stream functions in anisotropic porous media at a given point in time, provided that the hydraulic gradient field is known at the point in time. Application of the χ and λ equations is demonstrated by considering steady state groundwater flow under the Borden landfill in Ontario, Canada. The two equations will be valuable in visualization of groundwater flow and contaminant transport, design of numerical solution grids for contaminant transport modeling, and design of contaminant remediation well systems.
32 citations
TL;DR: In this article, a comparison of flow nets based on pseudopotential lines and hydraulic head lines is made in simulation of contaminant transport in saturated groundwater flow systems. But the results are limited to the case of an isotropic porous medium.
Abstract: Construction of flow nets in most hydrogeologic field problems is complicated by nonexistence of orthogonality between streamlines and hydraulic head lines in anisotropic porous media. The nonexistence of orthogonality can be circumvented by transformation of the anisotropic porous medium into an isotropic one. Flow nets are valuable in generation of a numerical solution grid for a contaminant transport equation formulated along the direction of flow and the direction orthogonal to flow. Effect of flow domain transformation on contaminant transport simulation is not known. The flow domain transformation can be avoided by constructing flow nets with streamlines and pseudopotential lines. The pseudopotential lines are based on the theory of pseudopotential function. A discussion of the theory in isotropic porous media exists in literature. To my knowledge, this is the first time that the theory is being extended to anisotropic porous media. An integration procedure is used to evaluate values of pseudopotential function and hydraulic head along a streamline. A comparison of flow nets based on pseudopotential lines and hydraulic head lines indicates that pseudopotential lines are more useful than hydraulic head lines in simulation of contaminant transport in saturated groundwater flow systems.
8 citations
TL;DR: In this article, the authors used pseudopotential surfaces to visualize groundwater flow and transport processes in the Borden Landfill in a 3D model of the underground aqua system.
Abstract: Scientific visualization is increasingly being applied in many large-scale groundwater modeling efforts as an effective means of presentation and interpretation of model results An interpolation or statistical approach is applied to develop three-dimensional spatial distributions of geologic, hydraulic, and chemical data from a model or field measurements The distributions become the basis for evaluating spatial variation of data The evaluation is accomplished by displaying data in the form of isosurfaces of values of data Or as contours of data on a surface or plane This approach of analyzing data is known as data visualization In addition to data visualization, some of the problems encountered in groundwater hydrology require visualization of groundwater flow and transport processes Display of hydraulic and chemical data for analysis of groundwater flow and transport processes is herein referred to as process visualization In both data and process visualization, hydraulic and chemical data are displayed as color contours or isolines on surfaces However, in data visualization the surface on which data are displayed may be oriented in any direction, whereas in process visualization the surfaces need to be tangential or orthogonal to the direction of groundwater flow In three-dimensional groundwater flow, stream surfaces and pseudopotential surfaces are tangential and orthogonal, respectively, to the direction of groundwater flow Therefore stream and pseudopotential surfaces provide natural platforms on which to visualize groundwater flow and transport processes To demonstrate application of stream and pseudopotential surfaces in process visualization, the three-dimensional groundwater flow beneath the Borden Landfill is considered
3 citations
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TL;DR: In this paper, the authors present a survey of dynamic programming models for water resource problems and examine computational techniques which have been used to obtain solutions to these problems, including aqueduct design, irrigation system control, project development, water quality maintenance, and reservoir operations analysis.
Abstract: The central intention of this survey is to review dynamic programming models for water resource problems and to examine computational techniques which have been used to obtain solutions to these problems. Problem areas surveyed here include aqueduct design, irrigation system control, project development, water quality maintenance, and reservoir operations analysis. Computational considerations impose severe limitation on the scale of dynamic programming problems which can be solved. Inventive numerical techniques for implementing dynamic programming have been applied to water resource problems. Discrete dynamic programming, differential dynamic programming, state incremental dynamic programming, and Howard's policy iteration method are among the techniques reviewed. Attempts have been made to delineate the successful applications, and speculative ideas are offered toward attacking problems which have not been solved satisfactorily.
524 citations
TL;DR: In this paper, a numerical model based on rectangular grids is proposed to simulate mixing in aquifers, and the authors show that the model-dependent transverse dispersion caused the modeled plume to degrade much faster and therefore appear much shorter than the actual plume.
218 citations
TL;DR: The comprehensive reviews on the use of various programming techniques for the solution of different optimization problems have been provided and conclusions are drawn where gaps exist and more research needs to be focused.
194 citations
27 May 2018
TL;DR: In this paper, the authors model water resources management at the basin level and propose a model for basin level water resource management at basin level, which is based on the model presented in this paper.
Abstract: Modeling water resources management at the basin level , Modeling water resources management at the basin level , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
140 citations
TL;DR: The reviews on the combined applications of simulation and optimization modeling for the conjunctive use planning and management of surface water and groundwater resources for sustainable irrigated agriculture are done and presented in this paper.
128 citations