Phd Degree / Doktora

Permanent URI for this collectionhttps://hdl.handle.net/11147/2869

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  • Doctoral Thesis
    Hydrological and Meteorological Drought and Trend Analysis in Afghanistan and Their Implications on Transboundary Rivers
    (01. Izmir Institute of Technology, 2022) Hayat, Ehsanullah; Tayfur, Gökmen
    Afghanistan as a landlocked country located within central and southwestern Asia has an arid to semi-arid climate. Most of the people are involved in agricultural activities and major part of the country's gross domestic product depends on agriculture, but the country has the lowest water storage capacity. Consecutive periods of droughts and rapid snowmelt due to climate change have made it more challenging for convenient water resources management practices. Other major concern is transboundary water that flows to downstream countries without any sharing agreement rather than one on the Helmand River. Therefore, this study first aims to investigate the historical hydrological and meteorological drought characteristics across the whole country using Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) for meteorological drought analysis for a period 1979-2019, and Streamflow Drought Index (SDI) is used for hydrological drought analysis using two different time series (1960-1979 and 2008-2020) from 55 hydro-meteorological stations. Missing streamflow data in four stations across four transboundary River Basins (RBs) of the country is modeled using Remote Sensing (RS) techniques via Landsat satellite imagery time series data from 1988 to 2021, and which is the novelty of this study. Afterwards, trends in streamflow, precipitation and temperature are examined using Mann-Kendall's and Sen's slope statistical tests. A four decadal countrywide drought maps are also generated. Finally, the effects of droughts and trends on transboundary rivers in the country are investigated. Data from (55) ground stations is used for this purpose in this study.
  • Doctoral Thesis
    Three Dimensional Numerical Modelling of Recharce: Case Study: Eğri Creek Sub-Basin, İzmir
    (01. Izmir Institute of Technology, 2022) Şahin, Yavuz; Tayfur, Gökmen; Baba, Alper
    Although the science of water management has experienced significant improvements over the past century, many issues still require the attention of the scientific community. Global change, growing population and increasing pressure on existing water supplies have intensified the need for further improvement of water resources management practice. The purpose of this special issue is to present some of the latest research carried out in the area of water resources management under uncertain and changing conditions. Study in this issue highlight recent consuming in this basin covering all the surface & groundwater of the hydrologic cycle. The large demand for drinking, irrigation and industrial water in the region of K. Menderes Basin. The main objective of the study is to emerge capacity of surface and groundwater. Also, notice that decreasing groundwater level in basin. This river basin agricultural dominant has fertile land and range of harvest diversity in all season. In dry periods, Groundwater level has been facing decreases for past 30 years. Every private farm has private wells that were drilled without permission. These cause depletion of groundwater and restraining the usage of groundwater. Another subject is industrial usage of groundwater and increasing population in area. For this purpose, surface artificial recharge methods in conjunction with underground dam construction were investigated in Egri Creek sub-basin. Thus, their contributions to the groundwater levels were investigated with the help of a numerical model.