İnşaat Mühendisliği

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Browsing İnşaat Mühendisliği by Subject "Aquifers."

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    Artificial neural networks approach for the determination of aquifer parameters
    (Thesis (M.S.)-Bogazici University. Institute for Graduate Studies in Science and Engineering, 2008., 2008.) Şahin, A. Ufuk.; Avcı, Cem.
    The determination of the aquifer parameters with sufficient accuracy is an important issue in the application of the mathematical models which have been developed for the groundwater systems. Recently, Artificial Neural Networks (ANNs) approach has become popular trend in the solutions of several hydrological problems. ANNs have the ability of learning and processing the introduced data without the need for the full understanding the physical world of the problems at the hand. In this research, ANN approach has been utilized to determine confined aquifer parameters such as transmissivity and storativity. Furthermore, an iterative ANN model has been proposed to determine leaky confined aquifer parameters. The results that have been obtained by ANN models have been also compared to the conventional curve matching procedures that are employed for the determination of aquifer parameters. As a second dimension of this thesis, a numerical experiment has been conducted to contour transmissivity distribution of a hypothetical aquifer by the ANN approach. The performance of the ANN model has been investigated by comparing the solutions of mathematical methods, namely Radial Basis Function and Ordinary Kriging, which are used in data interpolation. As a conclusion, the ANN approach has been successfully applied to determine aquifer parameters. ANN models demonstrate that the ANN approach can be an alternative modeling technique for the solution of various Hydrological problems.
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    Incremental area method approach for the determination of aquifer parameters and aquifer systems identification
    (Thesis (Ph.D.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2012., 2012.) Şahin, A. Ufuk.; Avcı, Cem.
    Groundwater is one of the main freshwater resources for the demand of potable water, agriculture and industry. The protection and remediation of groundwater sources have become an important issue in order to provide sustainable development for the societies. To construct a proper remediation scheme for the contaminated groundwater resources, the mathematical and physical models require parameters which can be obtained from aquifer pump tests. The accurate and reliable determination of aquifer parameters is called as an inverse problem in the groundwater engineering literature. The performance of the conventional estimation methods developed and commonly used for the ideal aquifer conditions is insu cient when the aquifer media have a heterogeneous character. In this thesis, a new estimation approach, as simple as the traditional techniques, referred as Incremental Area Method (IAM) has been introduced to analyze transient pumping response of an aquifer under heterogenic circumstances. The potential uses and limitations of the proposed method have also been investigated for various aquifers pump test data. Furthermore, the spatial dependency of aquifer heterogeneity has been analyzed using Inverse Solution Algorithm (ISA) which was rst established for the petroleum engineering reservoir cases. As a conclusion, the outcome of this research indicate that utilizing both the suggested IAM and adapted ISA to groundwater bearing ow problems leads to a realistic and robust interpretation of aquifer heterogeneity obtained from drawdown tests.