Multi criteria hydrological modeling and forecasting study in Coruh basin

The increase in global temperatures, undesireably affects the continuously increasing world population and reveals the importance of the science of hydrology. The efficient use of water resources in the country as well as drought and flood control, is crucial in terms of water resources management. For this reason, monitoring the amount of accumulated snow in the higher parts of Coruh Basin, hosting Turkey's major dams such as Yusufeli and Deriner, is vital in terms of modeling and forecasting the expected flow. In this study, the upstream part of the Coruh Basin is selected where a significant portion of the streamflow comes from snowmelt during spring and early summer months. In order to better understand the properties of this area of interest, various surface analyses have been carried out with the GIS platform and the snow potential of the region is examined using different satellites. Verification of snow algorithm is evaluated by comparing MODIS images with finer resolution Landsat satellite images as well as ground observation data. Hydrologic modeling is performed utilizing the HBV model with hydro-meteorological data for 2003-2015 water years and the model is calibrated by two different methods. The performance in terms of model efficiency using the GAP method is calculated as 0.86 for the calibration and 0.77 for the validation period. Multi-criteria hydrological modeling is applied using the Monte Carlo method, exploiting satellite snow cover images besides flow data. After applying sensitivity and uncertainty analysis on the model parameters, it is observed that multi-criteria modeling is effective in reducing the uncertainty of the parameters. As a final result, ensemble runoff forecasts are generated with several best model parameters using 1-day and 2-day ahead numerical weather prediction data for the snowmelt period (March-June) of 2015 water year. The study performed and the results achieved serve as an example of the conceptual hydrological modeling studies on the selected region and have the potential to lead for similar snow dominated basins.