Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Conference Object Simulation of Groundwater Flow in the Gediz River Basin(European Water Resources Association, 2015) Elçi, Alper; Şimşek, Celalettin; Gündüz, Orhan; Baba, Alper; Acınan, Sezen; Yıldızer, Nilgün; Murathan, AlimThe objective of this paper is to present the approach and results of a groundwater flow modeling study that was conducted for the Gediz River Basin (GRB), located in western Turkey. The GRB is one of the most important, largest and stressed river basins in Turkey. This basin is agriculture-dominant; however significant competition for water exists among various stakeholders and sectors. The model is set up as a two-dimensional, finite-difference MODFLOW-2005 model that is solved for steady-state conditions, representing average annual groundwater flow in the basin. The main purpose of the groundwater flow model is to determine groundwater flow dynamics and water budget for the alluvial aquifers of the GRB. Pumping wells in the GRB predominantly withdraw water from these aquifers. A model-based estimate of the hydraulic conductivity distribution is also obtained. A two-stage modeling approach is taken to determine boundary conditions of the alluvial aquifer model domain. This approach results in two independently calibrated models that are referred as baseline and alluvial flow models. Modeled groundwater heads of both models provide an acceptable fit to observed data. The range of hydraulic conductivity (K) values is from 0.01 to 4451 m/d indicating a very heterogeneous aquifer. The median K value is 34.92 m/d and the standard deviation is 366.45 m/d. According to the baseline flow model budget, it can be concluded that the most significant groundwater input for the entire GRB is leakage from surface water such as dam reservoirs and the Gediz riverbed. In the alluvial aquifer, surface water still plays an important role in the water balance, however lateral flows across aquifer boundaries are the most important component. Also, groundwater extraction is larger than groundwater recharge by precipitation.Article Citation - WoS: 22Citation - Scopus: 26Fuzzy Logic for Rainfall-Runoff Modelling Considering Soil Moisture(Kluwer Academic Publishers, 2015) Tayfur, G.; Brocca, L.This study developed Mamdani-type fuzzy logic model to simulate daily discharge as a function of soil moisture measured at three different depths (10, 20 and 40 cm) and rainfall. The model was applied to 13 km2 size Colorso Basin in central Italy for a period from October 2002 to April 2004. For each variable of soil moisture, rainfall, and discharge, 9 fuzzy subsets were employed while 30 fuzzy rules, relating the input variables (soil moisture and rainfall) to the output variable (discharge), were optimized. The model employed the min inferencing, max composition, and the centroid method. The model application results revealed that Mamdani-type fuzzy logic model can be employed to incorporate soil moisture along with rainfall to simulate discharge. Using soil moisture measured at 40 cm soil depth along with rainfall produced better simulation of discharge with NS=0.68 and R= 0.82. The performance of the model was also tested against a conceptual rainfall- runoff model of MISDc (Modello Idrologico Semi-Distribuito in continuo). MISDc couples an event-specific component with a module for continuous time soil water balance for taking into account the variable antecedent wetness conditions. The MISDc model requires estimation of seven parameters and the measurements of the hydrometeorological variables such as rainfall and air temperature. The comparative study revealed that fuzzy model performs better in capturing runoff peak rates and overall trend of high and small flooding events. © Springer Science+Business Media Dordrecht 2015.