WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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2003 - 200912010 - 20152

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Institution Author: search.filters.institutionAuthor.Tayfur, GökmenWoS Q: search.filters.wosQuartile.N/A

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Now showing 1 - 3 of 3
  • Conference Object
    Upscaling Surface Flow Equations Depending Upon Data Availability at Different Scales
    (Springer Verlag, 2003) Tayfur, Gökmen
    St. Venant equations, which are used to model sheet flows, are point-scale, depth-averaged equations, requiring data on model parameters at a very fine scale. When data are available at the scale of a hillslope transect, the point equations need to be upscaled to conserve the mass and momentum at that scale, Hillslope-scale upscaled model must be developed if data are available at that scale. The performance of the three models applied to simulate flows from non-rilled surfaces revealed that the hillslope-scale upscaled model performs as good as the point-scale model though it uses far less data. The transectionally-upscaled model slightly underestimates the observed data.
  • Conference Object
    Reverse Flood Routing in Rivers
    (International Association for Hydro-Environment Engineering Research, 2015) Tayfur, Gökmen; Moramarco, Tommaso
    This study developed model to do riverse flood routing in natural channels. The developed model has basically four components: (1) it expresses an inflow hydrograph by a Pearson Type-III distribution, involving parameters of peak discharge, time to peak, and a shape factor; (2) it employs the basic continutiy equation for flow routing, (3) it relates the storage to downstream flow stage and channel characterictis; and (4) it relates the lateral flow to downstream flow discharge with coefficients. The parameters, coefficients and exponents of the models were obtained using the genetic algorithm method. The developed models are applied to generate upstream hydrographs, using just downstream station information for Ponte Nuovo and Monte Molino river reach of 30.8 km distance within the same basin where the wave travel time is 3h and drainage area is about 1135 km(2). Inflow hydrographs were generated and compared against the observed ones. The model simulation of inflow hydrographs were satisfactory.
  • Article
    Modeling Water Stress Effect on Soil Salinity
    (Springer Verlag, 2011) Tayfur, Gökmen
    As it is widely known the earth is experiencing a climate change. The primary effect of this change is the increase trend in global temperature. This, in turn, results in increased number of events in flooding, and drought in different parts of the world. A secondary effect is the change in water and soil salinity. A considerable portion of the cultivated land in the world is affected by salinity, limiting productivity potential. About 20 million ha of total 230 million ha of irrigated land in the world are salt affected. The climate change is expected to worsen this situation. This study explores the water stress effect on soil salinity. For this purpose, a model is developed to simulate salt transport in a layered soil column. The soil salinity transport model development involves two parts: (1) modeling salt movement through sail layers due to runoff, percolation, and lateral subsurface flow, and (2) modeling dissolution and precipitation of gypsum which acts as sink or source for salts in soil. The model is calibrated and validated with measured data. The soil is irrigated under optimal and water stress irrigation conditions. The major model parameters affecting the soil salinity are found to be wilting point, field capacity, hydraulic conductivity, initial soil salinity, and soil gypsum concentration. The results have revealed that water stress results in high concentration of salt accumulation in soil columns.