Water and Wastewater Consulting Engineers Journal of Water and Wastewater; Ab va Fazilab (in persian) 1024-5936 18 4 2007 12 01 Effect of El Nino-Southern Oscillation on Annual Maximum Flood in Southwestern of Iran Effect of El Nino-Southern Oscillation on Annual Maximum Flood in Southwestern of Iran 66 78 2160 FA Amin Haghnegahdar Former Research Associate, Soil Conservation and Watershed Management Research Institute Bahram Saghafian Assoc. Prof., Soil Conservation and Watershed Management Research Institute Roohangiz Akhtari Former Research Associate, Soil Conservation and Watershed Management Research Institute Journal Article 2006 03 08 Flood forecasting and the study of the factors involved in flood events form important issues of concern in water resources management. In recent years, the influence of large-scale global climate phenomena on flood peaks has attracted more attention. In this paper, the effect of El Nino-Southern Oscillation (ENSO) is investigated on annual maximum flood (AMF) in Iran’s southwestern basins. The basins are located upstream of Dez and Karun-I dams. ENSO effects on probability, magnitude, and intensity (probability times magnitude) of AMF in the Esfand-Farvardin (March-April) period are examined. The results indicate that following El Nino, the probability of an AMF occurrence larger than the AMF corresponding to neutral ENSO conditions is higher in the study period. The opposite is true for La Nina conditions. It is also seen that El Nino effects are more intense than those of La Nina period. Flood forecasting and the study of the factors involved in flood events form important issues of concern in water resources management. In recent years, the influence of large-scale global climate phenomena on flood peaks has attracted more attention. In this paper, the effect of El Nino-Southern Oscillation (ENSO) is investigated on annual maximum flood (AMF) in Iran’s southwestern basins. The basins are located upstream of Dez and Karun-I dams. ENSO effects on probability, magnitude, and intensity (probability times magnitude) of AMF in the Esfand-Farvardin (March-April) period are examined. The results indicate that following El Nino, the probability of an AMF occurrence larger than the AMF corresponding to neutral ENSO conditions is higher in the study period. The opposite is true for La Nina conditions. It is also seen that El Nino effects are more intense than those of La Nina period. https://www.wwjournal.ir/article_2160_1819932ff5cf474f4f19e7c7024640c2.pdf