Determination of hydraulic parameters of semi-infinite aquifers using Marquardt algorithm

Taşkan, Cüneyt
In this study, transmissivity and storage coefficient of a semi-infinite, confined, homogeneous and isotropic aquifer, where the flow is one-dimensional and linear, are determined using Marquardt algorithm, considering two independent cases: constant drawdown in the adjacent stream; or constant discharge from the aquifer due to pumping at a constant rate. In the first case piezometric head and discharge measurements are utilized. Hydraulic diffusivity, which is the ratio of transmissivity to storage coefficient, is determined from piezometric head measurements; whereas their product is determined from discharge measurements. Then, the two parameters are calculated easily. In the second case piezometric head observations are utilized only and transmissivity and storage coefficient are determined simultaneously. Convergence to true values is very fast for both cases even for poor initial estimates. Three examples, two using synthetic data for both cases and one using actual field data for the second case, are presented. Conventional type-curve matching method is used for comparison of the results. It is observed that the results of Marquardt algorithm are in a reasonable agreement with those of type-curve matching method.


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Dündar, Serdar; Önder, Halil; Department of Civil Engineering (2005)
Laplace transform step-response functions are presented for one dimensional transient flow in fractured semi-infinite & finite aquifers. Unsteady flow in the aquifer resulting from a constant discharge pumped from the stream is considered. Flow is one-dimensional, perpendicular to the stream in the confined aquifers. The stream is assumed to penetrate the full thickness of the aquifer. The aquifers may be semi-infinite or finite in width. The Laplace domain solutions are numerically inverted to the real-tim...
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Bakar, Ürün; Önder, Halil; Department of Civil Engineering (2010)
In this study, piezometric heads in a composite aquifer composed of an alluvial deposit having a width adjacent to a semi-infinite fractured rock are determined. One dimensional transient flow induced by a constant discharge pumping rate from a stream intersecting alluvial part of the aquifer is considered. Parts of the aquifer are homogeneous andisotropic. Equations of flow, initial and boundary conditions are converted to dimensionless forms for graphical presentation and the interpretation of results ind...
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Zaloğlu, Cihan; Göğüş, Mustafa; Department of Civil Engineering (2014)
The goal of this study is to estimate the critical submergence depths of horizontal water intakes that have symmetrical and asymmetrical approach flow conditions by using empirical equations. Therefore a series of experiments were performed in a reservoir-pipe system dominated by gravity and controlled by a valve. On account of adjustable lateral walls, symmetrical and asymmetrical flow conditions were created at various Froude numbers. For a wide range of discharges and for three different pipe diameters, ...
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Şimşek, Çağdaş; Tokyay, Nuray; Department of Civil Engineering (2006)
In the scope of the study, prismatic roughness elements with different longitudinal spacing and arrangements have been tested in a rectangular flume in order to reveal their effects on fundamental characteristics of a hydraulic jump. Two basic roughness types with altering arrangements have been tested. Roughness elements of the first type extends through the channel width against the flow with varying length and pitch ratios for different arrangements. The second type is of staggered essence and produced b...
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Akdoğan, Tevfik; Merzi, Nuri; Department of Civil Engineering (2005)
In spite of a wide research, design of water distribution networks are not realized using optimization techniques. One reason for this fact is, design of water distribution networks is evaluated, mostly, as a least-cost optimization problem where pipe diameters being the only decision variables. The other motivation for preferring the traditional modeling practice is that, existing optimization algorithms are not presented to the user as friendly as it should be. In fact, water distribution systems are very...
Citation Formats
C. Taşkan, “Determination of hydraulic parameters of semi-infinite aquifers using Marquardt algorithm,” M.S. - Master of Science, Middle East Technical University, 2004.