Karst havza taşkınlıklarının yüzeysel akış bileşenlerinin analizi

Abstract

the expected base flow hydrograph - f or the mean flood day, or as the average base flow observed during the flood season. If similar studies are carried out on many stations with homogenous period of records, and if the base flow can be separated more precisely, it seems quite possible to extract more reliable conclusions about the floods in karst river basins those which may also be extended for the project sites where streamflow records are not available. V

SYNOPSIS Almost one third of Turkey's surface area is covered by karstified limestones. The springflows discharging from these formations affect the structural properties as weel as the quality and quantity of the river flows. In this study, the role of the karst media and of the base flows ön statistical and frequency distribution parameters of annual peak flows has been investigated. For this purpose, peak flows (as annual maxima) at seven representative streamgaging stations sited in five karstic river basins are analyzed. The base and the surface flow components of the annual maxima are separated by introducing a graphical procedure based on annual hydrographs of daily flows. Frequency analyses with eight theoretical distribution models are carried out for the total values of the annual peak flows and for the surface flow components in order to infer on how the base flow affects sample statistics and frequency distributions of the peak flow sequences. The computational results for the seven streamgaging stations revealed that the base flow components considerably reduce the variance, however have no significant influence on the frequency distribution model. Furthermore, it may be concluded that the frequency distribution characteristics and the return period coefficients of the represen tative stations, except those of Homa and Tanır, may be assumed quite similar to each other. Because of the random character of the peak flood days and of the storm precipitation, it is concluded that the base flow during the flood period varies randomly in nature. Hence, it seems rather reasonable to add a base flow contribution to the surface flow component of a given recurrance interval either as the ordinate of IVthe expected base flow hydrograph - f or the mean flood day, or as the average base flow observed during the flood season. If similar studies are carried out on many stations with homogenous period of records, and if the base flow can be separated more precisely, it seems quite possible to extract more reliable conclusions about the floods in karst river basins those which may also be extended for the project sites where streamflow records are not available. V