Frequency analysis of low flows in intermittent and non-intermittent rivers from hydrological basins in Turkey

Eris E. , Aksoy H., Önöz B., ÇETİN M., Yuce M. I. , SELEK B., ...More

WATER SCIENCE AND TECHNOLOGY-WATER SUPPLY, vol.19, no.1, pp.30-39, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 19 Issue: 1
  • Publication Date: 2019
  • Doi Number: 10.2166/ws.2018.051
  • Page Numbers: pp.30-39
  • Keywords: frequency analysis, intermittent river, low flow, low flow-duration-frequency curve, CLIMATE-CHANGE, L-MOMENTS, REGIONALIZATION, SOCIETY, IRRIGATION


This study attempts to find out the best-fit probability distribution function to low flows using the up-to-date data of intermittent and non-intermittent rivers in four hydrological basins from different regions in Turkey. Frequency analysis of D = 1-, 7-, 14-, 30-, 90- and 273-day low flows calculated from the daily flow time series of each stream gauge was performed. Weibull (W2), Gamma (G2), Generalized Extreme Value (GEV) and Log-Normal (LN2) are selected among the 2-parameter probability distribution functions together with the Weibull (W3), Gamma (G3) and Log-Normal (LN3) from the 3-parameter probability distribution function family. Selected probability distribution functions are checked for their suitability to fit each D-day low flow sequence. LN3 mostly conforms to low flows by being the best-fit among the selected probability distribution functions in three out of four hydrological basins while W3 fits low flows in one basin. With the use of the best-fit probability distribution function, the low flow-duration-frequency curves are determined, which have the ability to provide the end-users with any D-day low flow discharge of any given return period.