Regionalisation of discharges having certain exceedance probabilities and Eastern Black Sea Basin sample

In many of water engineering studies, it is necessary to determine the amount of water or the probability of discharge at a certain value. However, current discharge measurements are limited and located in discharge gauging stations (DGS). Flow duration curves (FDC) belonging to each DGS can be obtained, but it is necessary to estimate discharge values of the areas having no or insufficient discharge data. For this purpose, studies based on the regionalization of discharge values can be applied. In this study, discharge values of 39 DGS located on Eastern Black Sea Basin in Turkey, and temperature and precipitation of weather stations in the region have been obtained. Drainage areas have been determined. Total annual precipitation and temperature values of DGS have been obtained by using Thiessen method. Values having 20%, 30%, 50%, and 90% exceedance probabilities of annual FDC, have also been correlated with basin characteristics using 10-year average daily discharges. Drainage area, drainage density and mean slope of tributary values were chosen as topographic; and mean annual precipitation height and annual temperature values chosen as climatic parameters. As a result, in the ungauged areas, 20%, 30%, 50%, and 90% exceedance probabilities of annual FDC have been estimated by some basin properties and the results were examined.