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


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Eris E., Aksoy H., Önöz B., ÇETİN M. , Yuce M. I. , Selek B., et al.

WATER SCIENCE AND TECHNOLOGY-WATER SUPPLY, cilt.19, ss.30-39, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 19 Konu: 1
  • Basım Tarihi: 2019
  • Doi Numarası: 10.2166/ws.2018.051
  • Dergi Adı: WATER SCIENCE AND TECHNOLOGY-WATER SUPPLY
  • Sayfa Sayısı: ss.30-39

Özet

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.

ABSTRACT

This study attempts to find out the best-fit probability distribution function to low flows using the upto-date data of intermittent and non-intermittent rivers in four hydrological basins from different regions in Turkey. Frequency analysis of D¼ 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 functions family. Selected probability distribution functions are checked for their suitability to fit each D-day low flow sequence. LN3 mostly conforms 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 has the ability to provide the end-users with any D-day low flow discharge of any given return period.

Key words  frequency analysis, intermittent river, low flow, low flow-duration-frequency curve