Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7755

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2002 - 200932010 - 20192

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Author: search.filters.author.Tayfur, GökmenScopus Q: search.filters.scopusQuartile.N/A

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  • Master Thesis
    Hec Hms Hydrological Model Application Using Scs Curve Number and Soil Moisture Accounting: Case Study of Alaşehir Basin
    (Izmir Institute of Technology, 2019) Akdeğirmen, Özgün; Baba, Alper; Tayfur, Gökmen
    Water is known as source of life throughout mankind’s history. According to first records of written history; Sumerians and Akkadians used water for their inland transportation and irrigation systems. With first settlements, mankind’s dependency to water has been increased and became one of the most substantial natural resource in our modern age. Importance of this resource even more solidifies when we consider its property of being limited. With realization of global climate change in early 19th century; treat to this limited resource has been revealed. Approximately 68% of the freshwater on earth reserved in glaciers and icecaps and 30% is reserved in groundwater systems according to United States Geological Survey’s (USGS) studies. Owing to the quantity and less compromised to contaminants nature, majority of our freshwater needs met from groundwater. Although the importance of groundwater, its management have always been a challenge due to hard to quantify volumetric changings in aquifers. This study focused on creating a hydrological basin model to investigate volumetric recharge changings in groundwater system. Under scope of this study in an attempt to acquire groundwater recharge amounts; practicality of HEC-HMS hydrological modeling software has been investigated. A SCS Curve Number and Soil Moisture Accounting (SMA) loss methods has been chosen for HEC-HMS modeling application due to availability and accessibility of data that required for loss methods. After data collection from meteorological stations, core drill samples; both methods have been used in HEC-HMS simulation environment and their predictions have been compared. In the comparisons, it was determined that the SCS Curve Number method predicts higher flow potentials and groundwater infiltration amounts compared to the SMA method. Models foresee an average of 33.4 % of precipitation infiltrates into groundwater system.
  • Master Thesis
    Numerical Modeling the Flood Wave as a Result of Ürkmez Dam
    (Izmir Institute of Technology, 2018) Şahin, Gül Sümeyra; Tayfur, Gökmen
    Dams are constructed to provide benefits to society, hydropower generation, including water supply management and flood control. However, floods caused by failure of a dam is quite catastrophic for lives, properties and environment. Flow models for dam break scenarios ensures crucial information about land use planning and risk managment to minimize flood losses. In this study, estimation of flood innundated areas caused by flood triggered by failure of Urkmez Dam in Izmir is carried out by using HEC-RAS onedimensional (1D) unsteady flow routing model (full Saint Venant equations) and two dimensional model (2D) (full Saint Venant equations or Diffusion wave equations). The experimental distorted physical model provides controlling to simulations. The aim of the paper is to assess the risk of a dam failure potential by comparing performances of 1D and 2D simulations. Two models were compared considering the required data, data preparation, inundated area, flood velocity, flood depth, and flood waves.
  • Master Thesis
    B and Se Transport Modeling in Saturated/Unsaturated Zones
    (Izmir Institute of Technology, 2002) Yüreklitürk, O. Emin; Tayfur, Gökmen
    There has been renewed interest in the application of models to the transport of non-point source pollutants. However, very little work has been done to evaluate the performance of a functional transient-state model for the transport of a reactive solute over an extensive study period. This research consists of mathematical modeling to simulate water flow, boron and selenium transport through soil in tile-drained croplands.For Boron part a mathematical model was developed to simulate non-conservative boron transport. The dynamic two-dimensional finite element model simulates water flow and boron transport in saturated-unsaturated soil system, including boron sorption and boron uptake by root-water extraction. Two different models have been employed for the sorption of boron. Similarly, for selenium part a finite element model is developed to simulate species of selenium transport in two dimensions in saturated/unsaturated zones. The model considers water, selenate, selenite and selenomethionine uptake by plants. It also considers oxidation/reduction, volatilization, and chemical and biological transformations of selenate, selenite, and selenomethionine. Comparison of boron transport model results with observed data is satisfactory. The model employed with Langmuir isotherm was found to give slightly better simulation results when compared with the model employed with Freundlich. The sensitivity analysis results indicate that the irrigation scheduling and the irrigation water quality are very important parameters for boron accumulation in the soil. Also the adsorption isotherm parameters, which reflect us the soil properties, are found to be important for the boron movement in the soil. Comparison of selenium transport model with observed data is not quite satisfactory in accuracy when compared with the model for boron transport. This may be the result of the complexity of the mechanisms affecting the selenium transport in soil. There are too many parameters, and due to the errors depending on the parameters, the total error for the estimation of the total selenium increases.
  • Master Thesis
    Artificial Neural Networks Model for Air Quality in the Region of Izmir
    (Izmir Institute of Technology, 2002) Birgili, Savaş; Tayfur, Gökmen
    In this study, a systematic approach to the development of the artificial neural networks based forecasting model is presented. S02, and dust values are predicted with different topologies, inputs and transfer functions. Temperature and wind speed values are used as input parameters for the models. The back-propagation learning algorithm is used to train the networks. R 2 (correlation coefficient), and daily average errors are employed to investigate the accuracy of the networks. MATLAB 6 neural network toolbox is used for this study. The study results indicate that the neural networks are able to make accurate predictions even with the limited number of parameters. Results also show that increasing the topology of the network and number of the inputs, increases the accuracy of the network. Best results for the S02 forecasting are obtained with the network with two hidden layers, hyperbolic tangent function as transfer function and three input variables (R2 was found as 0,94 and daily average error was found as 3,6 j..lg/m3).The most accurate results for the dust forecasting are also obtained with the network with two hidden layer, hyperbolic tangent function as transfer function and three input variables (R2 was found as 0,92 and daily average error was found as 3,64 j..lg/m3).S02 and dust predictions using their last seven days values as an input are also studied, and R2 is calculated as 0,94 and daily average error is calculated as 4,03 Jlg/m3 for S02 prediction and R2 is calculated as 0,93 and daily average error is calculated as 4,32 Jlg/m3 for dust prediction and these results show that the neural network can make accurate predictions.
  • Master Thesis
    Groundwater Quality Assessment in Torbalı Region
    (Izmir Institute of Technology, 2002) Kırer, Tuğba; Tayfur, Gökmen
    Groundwater is an important source of irrigation, drinking water and other human activities. With the growth in population, agricultural and industrial activities and the groundwater usage have increased dramatically. However, not only the groundwater use, but also has the level of contamination in groundwater increased. In TorbalI region, drinking water and irrigation water are supplied from wells which are drilled mostly without permission. Excessive abuse of fertilizers, and pesticides in agricultural activities and industries cause to contaminate the groundwater. In order to investigate the quality of the groundwater in this regIOn, sampling locations were determined taking the geology and industry of the region into account. The samples were collected monthly for ten months. In this study, water quality parameters which are pH, temperature, electrical conductivity, calcium, magnesium, potassium, sodium, chloride, alkalinity, nitrate, nitrite, ammonia, copper, chromium, cadmium, lead, zinc, chemical oxygen demand (COD), and cyanide were examined to determine the groundwater quality and relationship between the parameters and the sources of contamination. The samples were classified as hard water. All of the samples had bicarbonate alkalinity. The study revealed the existence of agricultural contamination. Nitrate concentrations of the groundwater samples increased in summer and the concentrations of nitrate were higher than the permissible limit in some of the wells. Heavy metal contamination was not detected in the region. The concentrations of the parameters were not constant during the monitoring study. This may be because the leachate of wastewaters which are discharged suddenly and discontinuously.