Evaluation of future land use models within rainfall-runoff relation: the case of the Nilufer River Basin (Bursa)

In this study, variable hydrological parameters such as peak, mean and surface flows of Nilufer Stream Basin were evaluated due to the changing land use. In the first phase of the study, basic land use map was produced with pre-processing, pixel-based and object based classification methods on Landsat-5 satellite images from 1989 and 1999. Then, in order to obtain model accuracy, the 2009 and 2019 land use projections were produced and compared with reference images. The error matrices were determined. The accuracy rate didn't fall below 85.78 % for all years. After ensuring the model reliability, future land use projections were produced in accordance with the SWAT model. Then the peak, mean and surface flow values of the near future 2020-2049 which produced from reference land use map and near future 2020-2049 which produced from the 2029 land use map were compared. When the results are compared, the striking feature is the increase in all flow values with the change of land use. The most increase was seen at the peak flow values. The reflection values on sub-basins of the two maps were also compared. It observed that the mean flow values have decreased in some sub-basins where the forest and semi-natural areas that cover huge areas due to the changing land use. The peak flow, mean flow and surface flow values, which are the basin hydrology parameters of the distant future, were compared with 2070-2099 produced from the 2009 reference land use map, 2070-2099 produced from the 2029 land use map and 2070-2099 produced from the 2070 land use map. It was observed that there was an increase in value for all results. The difference between these values was observed at the highest peak flow values. As a result, basin hydrology parameters were analyzed that depend on changing land use. It has been a study in which the errors that may occur depending on the land use parameter kept constant in hydrology studies are shown.