Testing the Optimal Distribution of Rainfall Using Hyfran-Plus Software and Deriving Rainfall Intensity Duration Frequency (IDF) Curves for Al-Adhaim Basin, Iraq

sahar Resen; Abdulhussain Abbas; Zuhal Hamza

Article Details

Testing the Optimal Distribution of Rainfall Using Hyfran-Plus Software and Deriving Rainfall Intensity Duration Frequency (IDF) Curves for Al-Adhaim Basin, Iraq

Authors:

sahar Resen | Abdulhussain Abbas | Zuhal Hamza

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1D, pp.1-13

Document Type:

Article

Publication Date:

4/2026

Document Language:

English

Document ID (Org No.):

2001837004

pISSN:

2663-8754

Keywords:

Abstract:

 One of the most advanced ways to address the risk posed by natural hazards is to analyse rainfall events in each catchment accurately. This enables experts to make informed decisions and ensure compliance with safety standards and optimal hydraulic design. Examining rainfall events in the Al-Adhaim Basin in Iraq is particularly important in this respect. By performing a frequency analysis and selecting the most suitable distribution, one can obtain likely storm hyetographs and intensity curves, and observe the harmonic behaviour of rainfall patterns. Herein, eleven theoretical probability distributions, functions, including exponential, General Extreme Value, Gumbel, Weibull, normal, log normal (3 parameters), gamma, inverse gamma, generalised gamma, and Pearson Type III were developed to simulate the properties of the observed probability using the Hyfran Plus program. The best probability distribution was selected using the Akaike information criterion and the Bayesian Information Criterion. Among the evaluated probability distributions, the Gumbel distribution was objectively identified as the most appropriate for maximum-likelihood frequency analysis within the research region. In light of this, the Soil Conservation Service technique type II was used to produce synthetic storms lasting 24 hours to distribute rainfall depth, both cumulative and incremental, in the dry and semiarid region, with return periods of T = 5, 10, 25, 50, and 100 years. Based on these artificial storms, rainfall intensity-duration-frequency curves were produced.

Article Details

Testing the Optimal Distribution of Rainfall Using Hyfran-Plus Software and Deriving Rainfall Intensity Duration Frequency (IDF) Curves for Al-Adhaim Basin, Iraq

Authors:

sahar Resen | Abdulhussain Abbas | Zuhal Hamza

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1D, pp.1-13

Document Type:

Article

Publication Date:

4/2026

Document Language:

English

Document ID (Org No.):

2001837004

pISSN:

2663-8754

Al-Adhaim basin

Hyfran-Plus

Probability distribution functions

Gumbel distribution

return periods

IDF curves

Issues

Article Details

Testing the Optimal Distribution of Rainfall Using Hyfran-Plus Software and Deriving Rainfall Intensity Duration Frequency (IDF) Curves for Al-Adhaim Basin, Iraq

Authors: sahar Resen | Abdulhussain Abbas | Zuhal Hamza

Publisher: Iraqi Geologists Union (Union of Iraqi Geologists)

Journal: The Iraqi Geological Journal Vol.59 Issue 1D, pp.1-13

Document Type: Article

Publication Date: 4/2026

Document Language: English

Document ID (Org No.): 2001837004

pISSN: 2663-8754

Al-Adhaim basin

Hyfran-Plus

Probability distribution functions

Gumbel distribution

return periods

IDF curves

Issues

Authors:

sahar Resen | Abdulhussain Abbas | Zuhal Hamza

Publisher:

Iraqi Geologists Union (Union of Iraqi Geologists)

Journal:

The Iraqi Geological Journal Vol.59 Issue 1D, pp.1-13

Document Type:

Article

Publication Date:

4/2026

Document Language:

English

Document ID (Org No.):

2001837004

pISSN:

2663-8754