Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Determination of Flood Risk Areas and Development of Mitigation Strategies in Kabul River Basin, Afghanistan(01. Izmir Institute of Technology, 2023) Barez, Esmayel; Tayfur, Gökmen; Tayfur, Gökmen; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyFlooding is a devastating and natural catastrophe to population, environment, and socioeconomic development globally. Floods occur frequently in Afghanistan, especially in Kabul River Basin. Many geographical techniques have been established in recent years to map, predict and model flood risks. This research investigates identification of flood-prone zones and development of mitigation measures in Kabul River Basin. First, in this research, GIS and MCDA methodology was applied to generate flood risk map. Also, AHP method was applied to determine the best weights to be assigned to the factors that influence risk of flooding. A flood risk map of KRB was produced using 10 conditioning criteria; soil, rainfall, lithology, LULC, TWI, NDVI, distance to stream channels, curvature, elevation, and slope. Based on the weighted overlay integration of GIS-AHP technique, KRB was grouped into four flood vulnerability zones; very low, low, high, and very high. Generated flood risk map indicates a good match with the flood risk areas and location of past floods in the basin over recent years. Second, 2D HEC-RAS model and flood frequency analysis were developed for different scenarios to simulate the flow of river and to develope mitigation measures with a 500- year return period in the main river of Kunar and the lower Kabul sub-basin. Manning's n values were used to calibrate HEC-RAS model, and past flood events applied for validation. Flood mitigation strategies, including river restoration, construction of dam, and reservoir improvement were proposed on the Kunar and lower Kabul sub-basin. Keywords: Flood Inundation Map, Hydraulic Modelling, ArcGIS-MCDA.Master Thesis Developing Flood Mitigation Measures for Baledwayne City, Somalia, by Using the Hec-Ras Model(Izmir Institute of Technology, 2022) Tayfur, Gökmen; Tayfur, Gökmen; 03.03. Department of Civil Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis study covers the investigation of the flood mitigation measures required to protect the city of Baledwayne, which is located in the Hiran region of Somalia and has been subject to frequent floods recently. In the HEC-HMS model, the precipitation data measured in 2019 and DEM at the Baledwayne and Bulo-Burti stations of the Hiran region were used as input. The observed discharge in the Shabelle river in 2019 of both stations was imported into the model to compare the simulated rainfall-runoff hydrographs. The rainfall-runoff hydrographs of 2019 were simulated with the HEC-HMS model using these parameters, SCS Curve Number for analyzing runoff volume, Snyder Unit Hydrograph for estimating direct runoffs, and Constant Monthly for calculating the baseflow and Muskingum for channel routing. The outflow hydrographs at both stations were successfully simulated. With the 1D&2D HEC-RAS model, flood maps were generated using various alternatives to protect the study area from floods of Q500 flow rate with a return interval of 500 years. The Deyr 2019 flood event was used for the calibration of the model. The model determined the flood extent and depth of this flood event by changing the roughness coefficient at specific intervals. Various flood mitigation measures have been investigated after calibration. It has been found that the best protection can be achieved by the combination of these four flood mitigation measures: (1) rehabilitation of the Warabole diversion channel, (2) construction of detention ponds at the upstream of the floodplain, (3) levees along both sides of the river and (4) improvement of the river.