Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Author: search.filters.author.Gündüz, Orhan

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Now showing 1 - 6 of 6
  • Master Thesis
    Adalarda İklim Değişikliği Altında Doğal Yeraltısuyu Beslenmesinin Modellenmesi: Bozcaada Örneği (Türkiye)
    (2025) Türkseven, Özge Yaren; Baba, Alper; Gündüz, Orhan
    Küresel iklim değişikliği, yağış rejimlerindeki düzensizlik, artan sıcaklık ve buharlaşma oranları gibi faktörlerle su döngüsünü önemli ölçüde etkilemekte ve özellikle küçük ve sınırlı kaynaklara sahip adalar gibi hassas bölgelerde su kaynaklarının sürdürülebilirliğini tehdit etmektedir. Bu bağlamda, yeraltı suyu rezervleri, yüzeysel kaynakların yetersiz olduğu dönemlerde güvenilir bir alternatif oluşturmakta ve entegre su yönetimi stratejilerinde kritik bir rol oynamaktadır. Bu tez çalışması, Bozcaada Adası özelinde yeraltı suyu yenilenme potansiyelini belirlemeyi ve iklimsel değişkenlerin bu süreç üzerindeki etkilerini analiz etmeyi amaçlamıştır. Çalışma kapsamında, hem geleneksel yöntemlerden biri olan Klorür Kütle Dengesi (CMB) hem de süreç-temelli bir sayısal model olan HYDRUS-1D kullanılarak düşey su akışları modellenmiş, sensör verileri ve yerel toprak özellikleri dikkate alınarak düşey su hareketi simüle edilmiştir. Bu tür adalarda deniz suyu girişimin etkisinin yüksek olduğu görülmekte olup, bu nedenle geleneksel klorür yönteminden çok sayısal modellerin daha doğru sonuç verebileceğini göstermektedir. Özellikle Bozcaada gibi dış kaynaklara bağımlı küçük bölgelerde yeraltı suyu kaynaklarının korunması için hem niceliksel hem de niteliksel değerlendirmelerin önemini vurgulamaktadır. Nispeten düşük beslenme oranları, adanın mevcut su kaynaklarının yenilenmesinin sınırlı olduğunu göstermektedir. Bu nedenle, yerel yönetimler yağmur suyu hasadı, yeraltı barajları ve doğa temelli çözümler (NbS) gibi alternatif yaklaşımları araştırmalı ve uygulamalıdır. Elde edilen veriler ışığında, bu tez kapsamında somut bazı öneriler (YAS beslenme alanları, geçirimli alanlar, arıtılmış atık suyun kullanımı ve su hasadına gibi) sunulmuştur.
  • Master Thesis
    Drought Assessment in Afghanistan Using Remotely Sensed Data
    (2023) Anwari, Ezatullah; Gündüz, Orhan; Tayfur, Gökmen
    Afghanistan's climate ranges from arid to semi-arid because it is a landlocked country in central and southern Asia. The vast majority of people work in agriculture, and agriculture accounts for a significant portion of the nation's GDP. Climate change-related droughts that have occurred repeatedly have made it increasingly difficult to implement practical water resources management techniques. Another noteworthy concern involves transboundary water flowing downstream to neighboring countries without any established sharing arrangements. Consequently, this study aims to examine drought assessment in Afghanistan over the period from 1992 to 2021. This assessment will be based on various indices, including the Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI), Reconnaissance Drought Index (RDI), and Surface Runoff Index (SRI). Data used in this study are remotely sensed precipitation, temperature and surface runoff data. In order to make compression between short term period and long-term period each of the indices are calculated in three different time scales (3_month, 6_month and 12_month). At the end Afghanistan's yearly drought maps of each four indices for each of the three-time scales are drawn by Geographic Information System (GIS) and the results obtained are discussed. Accordingly, the results revealed that most of the country, notably the west of Afghanistan, has endured several, significant droughts over the last 20 years at least, and also due to regional climate variations (arid and semi-arid), these four indexes behave differently in specific situations.
  • Master Thesis
    Assessment of Land Use Change Impacts on Hydrological Parameters in Porsuk River Basin - Turkey
    (01. Izmir Institute of Technology, 2023) Zulal, Khalilullah; Gündüz, Orhan; Alp, Emre
    Land Use Land Cover (LULC) change is considered to play an essential role in river basin hydrology. Climate change, and increase in urbanization have disrupted the hydrological parameters pattern in Porsuk River Basin (PRB). The current study is aimed to investigate the LULC change impacts on surface runoff, groundwater, evapotranspiration, and lateral flow parameters in the five sub-basins of the PRB under different LULC development scenarios (1990 & 2006) and one climate period (1989- 2010) through hydrological modeling. In this study, the Soil and Water Assessment Tool (SWAT) model was utilized to analyze the hydrology of the river basin at watershed scale. The hydrological pattern characterization is based on five discharge gauges monitored by State Hydraulic Works (DSI) in the basin. The Kiranharmani, Parsibey, and Porsuk Ciftligi subbasins, the yearly increase in surface runoff reached 25%, 18%, and 12.91%, respectively, are more affected by landuse changes. The Scenario 2, contrary to Scenario 1, showed a noticeable reduction of groundwater infiltration in all subbasins with exception of Parsibey, due to rapid increased area of residential regions. In comparison to the 1990 LULC, changes in the 2006 LULC have a greater overall impact on hydrological processes in all sub-basins of the PRB. Therefore, it is believed that changes in specific LULC classifications can be linked to the reaction to changes in hydrological processes in a subbasin. Overall, this research is believed to be among the first to be done in the PRB, and the findings are thought to be helpful for water management.
  • Master Thesis
    Surface Water Quality Modeling for Best Management Practices - a Case Study From Bakırçay River Basin
    (01. Izmir Institute of Technology, 2021) Kazancı, Yiğithan; Gündüz, Orhan; Kazancı, Yiğithan; Baba, Alper; Baba, Alper; Gündüz, Orhan
    This study was carried out to analyze the water quality in the Bakırçay River basin, which is known to be exposed to intense industrial and agricultural pollutant loads. A mathematical model system called AQUATOOL was used to reveal the changes that the effects of anthropogenic and natural events in the basin will cause on the conservative water quality parameters and nutrients. Model results are given in wet (April) and dry (September) periods for 4 points determined from upstream to downstream in the basin on a spatial basis, and temporal evaluation is also given for 1 upstream river water body, 1 downstream river water body, and 1 lake water body. Seven best management practices scenarios were determined and implemented one after the other in the model. Spatially, the results reveal good water status for both the dry period and the wet period at the upstream points, while at the downstream points, all parameters except BOD5 and Dissolved Oxygen are found to be in poor condition. Besides, similar situations arise in spatial-based results, and despite the scenarios, parameters could not reach good water status except for the lake waterbodies. The improvement in lake results occurs due to dilution, not scenarios. With this study, the pollution load in Bakırçay River Basin and the effects it creates once again revealed that if the anthropogenic loads are not reduced, the water quality of the basin will reach irreversible points for many years. It is thought that this study can constitute a source document for decision-makers, especially in terms of efficiency comparisons in the best management scenarios to be applied.
  • Master Thesis
    Exposure and Risk Assessment for Arsenic in Simav Plain by Ingestion of Edible Crops
    (Izmir Institute of Technology, 2017) Terzi, Begüm; Sofuoğlu, Sait Cemil; Gündüz, Orhan
    Ingestion is the main route of exposure to arsenic. The pathways of concern are ingestion of drinking water and arsenic-accumulating plants. Simav plain has been shown to have the natural arsenic conamination of waters and soil. However, foodstuff was not made a subject of investigation. In this study, arsenic exposure via ingestion of edible plants cultivated in Simav plain was investigated based on the modeling of the measured soil concentrations and data collected from the literature, which were for bioconcentration factors, plant consumption rates, background arsenic concentrations in plants, plant root depths, and body weights. Eighteen plant species, which are bean, broccoli, cabbage, carrot, cauliflower, corn, cucumber, eggplant, garlic, lettuce, okra, onion, potato, radish, spinach, sunflower seed, tomato, and wheat were studied. Chronic-toxic and carcinogenic risks associated with the consumption contaminated foodstuff were assessed with two approaches: scenario based point estimates (deterministic approach) and population based estimates (probabilistic approach). Monte Carlo simulation was used to determine chronic-toxic and carcinogenic risks via ingestion of edible plants probabilistically. Wheat was found as the plant variety with the highest non-carcinogenic and carcinogenic risks which was followed by potato, tomato, cucumber, corn, cabbage, eggplant, and onion. Non-carcinogenic risk levels for broccoli, cauliflower, garlic, and radish were below the threshold level. However, their carcinogenic risk levels were considerable. The risk levels estimated in this study are exceptionally high, indicating consumption of the plants cultivated in Simav may pose significant chronic-toxic and carcinogenic health risks.
  • Master Thesis
    The Investigation of Seawater Intrusion of Coastal Aquifer in Karareis (karaburun Peninsula)
    (Izmir Institute of Technology, 2016) Mansour, Ahmed Y. S.; Baba, Alper; Gündüz, Orhan
    Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could easily be influenced by seawater. This study presents the development of conceptual and numerical model for the coastal aquifer of Karareis region in the western part of Turkey. The study also presents the interpretation and the analysis of the groundwater levels recorded by groundwater data loggers. Groundwater pumping from Karareis aquifer has increased significantly during the summer period to meet the agriculture and domestic water demands. Levels of groundwater were measured at nine locations in Karareis region; also water samples were collected and analyzed for some parameters. For this study SEAWAT code is used to solve the numerical model for the coupled density dependent flow system. The model was calibrated using the average of one-year dataset of collected groundwater levels. Model validation was handled using the average of groundwater levels measured over more one year. Five scenarios were tested to understand the effects of pumping and climate change on groundwater levels and seawater intrusion in the next ten years. The result of analysis demonstrated a high concentration of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion will extent about 420 m towards the land in the next ten years of increased pumping scenario, while a little change in water level and TDS concentration was recognized in climate change scenario. Results also showed that reducing the pumping from Karareis wells will be necessary to protect the freshwater from contamination by seawater.