Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Article Citation - WoS: 16Citation - Scopus: 19Comparative Analysis of Estimation of Slope-Length Gradient (ls) Factor for Entire Afghanistan(Taylor & Francis, 2023) Ansari, Ahmad; Tayfur, GökmenSlope length gradient (LS) is one of the crucial factors in the Universal Soil Loss Equations (USLE, RUSLE). This study aimed at estimating the slope-length and slope-steepness (LS) factor for the entire watersheds of Afghanistan by using three different methods, namely; (1) LS-TOOLMFD (Method 1); (2) The Method of Equations (Method 2); and (3) The approach of Moore and Burch (Method 3). The first method uses the digital elevation model (DEM) in the ASCII format, and the other two methods use the DEM in the spatial domain. The results show that the LS-factor of the study area ranges from 0.01 to 44.31, with a mean of 5.24 and standard deviation of 6.95, according to Method 1; 0.03 to 163.49, with a mean of 9.6 and standard deviation of 13.58, according to Method 2; and 0 to 3985, with a mean of 7.16 and standard deviation of 29.7, according to Method 3. The study reveals that Methods 1 and 2 are more appropriate than Method 3 because Method 3 yields high LS-factor values close to or at streamlines located near mountainous regions. The highest LS values are found to be in the northeast, north, and central regions of Afghanistan, which is consistent with the high mountains and deep valley geomorphology, indicating that these regions are particularly vulnerable to soil erosion by rainfall-runoff processes. The sediment delivery ratio (SDR) for the Upper-Helmand River Basin (Upper-HRB) is also estimated by the RUSLE, employing the LS factors produced by the three methods. The results revealed that the average annual soil loss is found to be, respectively, 9.3, 18.2, and 11.1 (ton/ha/year) by using the three methods, corresponding to SDR of 23.5%, 12.1%, and 19.9%.Article Citation - WoS: 13Citation - Scopus: 12Identification of Groundwater Potential Zones in Kabul River Basin, Afghanistan(Elsevier, 2021) Tani, Hamidullah; Tayfur, GökmenGroundwater (GW) plays a vital role in the socio-economic growth of Kabul River Basin (KRB) in Afghanistan. Since the GW resources in the basin have not been properly managed, there is a need for sound strategies by first identifying the potential GW zones. This study assesses the potential groundwater zones for the KRB using the Geographic Information Systems (GIS) and the Analytic Hierarchy Process (AHP). In this direction, seven different thematic maps of rainfall, lithology, land use/land cover, slope, soil, drainage density, and lineament density are first prepared using the GIS. The AHP is then employed to assess the weights of different themes. Finally, the weighted overlay option in the GIS is used to generate the map of the groundwater potential zones (GWPZ). The Very Good zones are mostly located in the downstream and central parts of the KRB, covering around 1543 km(2) area. The Good and the Poor zones are found to be randomly distributed, covering about 39 444 km(2) and 27 658 km(2), respectively. The Very Poor zones are located in the west, southwest, and in some central parts of the basin, covering about 2272 km(2). It is found that only 18% of the total average annual precipitated water of 6.88 x 10(9) m(3)/year infiltrates into the subsurface and ultimately contributes to recharging of the groundwater.Article Citation - WoS: 44Citation - Scopus: 47Predicting Flood Plain Inundation for Natural Channels Having No Upstream Gauged Stations(IWA Publishing, 2019) Kaya, C. Melisa; Tayfur, Gökmen; Güngör, OğuzFlow hydrographs are one of the most important key elements for flood modelling. They are recorded as time series; however, they are not available in most developing countries due to lack of gauged stations. This study presents a flood modelling method for rivers having no upstream gauged stations. The modelling procedure involves three steps: (1) predicting upstream hydrograph by the reverse flood routing method which requires information about channel geometric characteristics, downstream flow stage and downstream flow hydrographs; (2) modelling flood wave spreading using HEC-RAS. The hydrograph predicted by the reverse flood routing in the first step becomes an inflow for the HEC-RAS model; (3) delineating the flood-risk areas by overlapping the Geographical Information System (GIS)-based flood maps produced by the HEC-RAS to the related orthophoto images. The developed model is applied to Guneysu Basin in Rize Province in Eastern Black Sea Region of Turkey. The model-produced flood map is compared to the observed one with success.Conference Object Monitoring of Acid Mine Lakes by Unmanned Aerial Vehicle (uav) on Geographic Information System (gis) Around Can Region, Biga Peninsula, Nw Turkey(Muğla Sıtkı Koçman Üniversitesi, 2014) Yücel, Mehmet Ali; Şanlıyüksel Yücel, Deniz; Turan, Recep Yavuz; Baba, AlperIn the past three decades, a few small scale private enterprises have been operating around Can Region, Biga Peninsula, NW Turkey which is rich in lignite reserves. They have abandoned the operation land without providing any working of rehabilitation. during the operation of high sulfur content lignite, the topography have been damaged and this caused the large holes and deterioration in these areas. As a result of discharge of surface water the artificial lakes have been formed. In the course of the time, these lakes gain acidic character due to acid generation from pyrite oxidation. Significantly high acidity with low pH values ranging from 2.53 to 3.05 is recorded from AMLs.Conference Object Groundwater Resources in Local Development Strategies: Case of Izmir(International Water Association, 2017) Velibeyoğlu, Koray; Yazdani, Hamidreza; Baba, AlperRural socio economic development has gained utmost importance in Turkish Metropolitan Municipalities within the frame of recent legal changes extending boundaries towards their peripheral areas. With this regard, Ġzmir Metropolitan Municipality has completed series of local development strategies aiming at the sustainable development of the city‘s rural hinterland. For three fertile sub region of Izmir, namely as Yarımada, Gediz Bakırçay and Küçük Menderes, local development strategies were prepared consecutively. In the framework of local development strategies; agriculture, tourism, settlement pattern and culture, local innovation and entrepreneurship, and environmental issues and water resources were examined as project themes. Among them, water resources has utmost important since the local development of whole sectors are largely dependent on them. Therefore, local development strategies have underlined the reality of river basins and potentials and limitations on groundwater resources due to the fact that surface waters have already been contaminated.Conference Object The Impacts of Planning Criteria’s on Groundwater Sources: Case of Izmir New City Center(International Water Association, 2017) Yazdani, Hamidreza; Baba, AlperCities with historical background, according to their geographic or economic alteration generally possess different town centers. Mostly for better protection against human or non-human factors the center of cities are relocated. The city of Ġzmir is one the magnificent case of city center resettlements. The premier location of city that is estimated to be 5000-8000 years before was in Bornova reeds in the north. Far from the sea and as results of serious disease the settlement relocated to Smyrna in Bayraklı. Smyrna was then abounded after massive earthquakes. Pagos hills (Kadifekale) with its great defending potential become the next city of Smyrna. Then, the economic value of harbor and rail-way moved the city to the cost. In all this location selection, geographic characters present crucial role in optimizing the decision.Conference Object Evaluating Impacts of Urbanization on Recharge of Groundwater Resources: Case Study: Bornova Plain (izmir/Turkey)(International Water Association, 2017) Yazdani, Hamidreza; Kılıç, Çılga; Baba, AlperIncreasing the World‘s population and industrialization in parallel with urbanization has created serious problems on water resources. Over the next forty years it is expected to add 2,5 million people on world population. To fulfill the needs of increasing population, the water demand will increase but the increasing of demand towards water is more rapid than increasing of population. Urbanization is a global phenomenon that is quickly altering the physical structure of any region. Bornova plain is located in water basin of Ġzmir where it is the most important settlement of the Aegean Region from the ancient ages to the current era. In this study, impacts of urbanization and population growth on groundwater resources were analyzed using GIS in Bornova Plain, where it is one of the most important groundwater aquifers and it supports about 16% of domestic water resources of Izmir City.Article Citation - WoS: 76Citation - Scopus: 84Two-Dimensional Numerical Modeling of Flood Wave Propagation in an Urban Area Due To Ürkmez Dam-Break, Izmir, Turkey(Springer Verlag, 2016) Haltas, İsmail; Tayfur, Gökmen; Elçi, ŞebnemThis study investigated flood inundation in an urban area due to a possible failure of Ürkmez Dam in İzmir, Turkey. The estimation of flood hydrograph upon partial failure of the dam and routing of the flood hydrograph along the narrow valley downstream were first performed by the one-dimensional hydraulic routing model HEC-RAS. The two-dimensional hydraulic routing model FLO-2D is then used to simulate the spreading of the dam-break flood after the flood wave exits the valley. Land use and land cover digital maps were utilized to find the spatially varying roughness coefficient for the floodplain. The influence of the buildings on the flood propagation was represented in the numerical model by the area reduction factor as well as the width reduction factor. The peak flow depth, peak flow velocity and time moment of the peak flow depth maps were shown in the GIS environment. The results reveal that flow depths can reach about 3 m in the residential area. In about 40 min after the dam-break, houses in the large section of the town would be under the maximum flow depths. The two-dimensional hydrodynamic model results were tested against experimental dam-break flow data of the distorted physical model of Ürkmez Dam, which is consisted of the reservoir, dam body and downstream area including Ürkmez Town. The model successfully simulated experimental flow depth data measured at different measurement locations.Article Citation - WoS: 20Citation - Scopus: 23Change Detection and Visualization of Acid Mine Lakes Using Time Series Satellite Image Data in Geographic Information Systems (gis): Can (canakkale) County, Nw Turkey(Springer Verlag, 2014) Şanlıyüksel Yücel, Deniz; Yücel, Mehmet Ali; Baba, AlperCan, a county in the province of Canakkale, is one of the most prominent coal mining districts in Turkey. Many mining companies have been operating coal deposits for power generation and district heating in this region since 1980. Generally, small and medium-scale mining companies operate for short periods and abandon the operational land without providing any rehabilitation. Human intervention in the natural structure and topography of the earth surface causes large holes and deterioration in these areas. Artificial lakes occur because of surface discharge and underground leakage into abandoned open pit mines with high lignite sulfur content (0.21–14.36 wt %). Furthermore, these lakes gain acidic character due to acid generation from pyrite oxidation. Acid mine lakes are highly acidic (pH < 3.05) and have elevated concentrations of (Formula presented.), Fe and some metals. The main objective of this study is to evaluate the environmental conditions and demonstrate the development of a monitoring system for their possible changes in the acid mine lakes of the open cast lignite mining area on a regional scale. For this purpose, the data received from remote sensing satellites were used. Areal change detection and perimeter changes of nine acid mine lakes caused by coal mining companies in Can from 1977 to 2011, were determined using Landsat, Quickbird and Worldview satellite images. As a case study, an area of 9 km2 was chosen for the variety of acid mine lakes. Using GIS software, satellite images were analyzed in time series, borders of acid mine lakes were digitized and converted into vector data format. At this stage, prior to the digitization, in order to create contrast on the satellite images, “stretch type” and “stretch values” were changed. The areal and perimeter changes were computed and presented via tables and graphics. In addition, thematic maps of the acid mine lakes were created and visualized. The results show that the number of acid mine lakes increased and these caused environmental risks due to their hydrochemical properties and areal increments.