Comparative Analysis of Flood Frequency Analysis Techniques: A detailed study in Nallah Mahal, District Bagh, AJK

Abstract

Flood Frequency analysis is done for calculating flood peaks for different Return Periods. Hydraulic Structures like Dams, Bridges, Weirs and Barrages etc are designed on the basis of Flood Frequency Analysis. The data is used to calculate maximum floods peaks for different Return periods. Results are solely based on the quality and quantity of data and Method employed for calculation of Flood Frequency analysis. There are different statistical methods that are used to calculate Flood frequency analysis. Many of the times focus is given on only one type of method and there is always an ambiguity exists whether which method should be adopted. In this study flood frequency analysis has been completed for Nallah Mahal Bagh AJK using all the major methods like Gumble’s Extreme Value Distribution, Log Normal (LN), Log Pearson Type III (LP III) Distribution and General Extreme Value Distribution to predict and analyse maximum flood peaks for different return periods. The annual peak discharge data from 1970 to 2012 (41 years flood peak data) was collected from Power Development Organization (PDO) Muzaffarabad AJK. The data was divided into different data sets A, B, C and D after which Flood frequency analysis was performed using all four methods. After Detailed analysis it can be established that Gumble’s Extreme Value Method is the most suitable approach for predicting the peaks against return periods.