Application of regional frequency analysis to Ceyhan and Seyhan river basins

ABSTRACT MSc. THESIS APPLICATION OF REGIONAL FLOOD FREQUENCY ANALYSIS TO CEYHAN AND SEYHAN RIVER BASINS Neslihan SEÇKİN DEPARTMENT OF CIVIL ENGINEERING INSTITUTE OF NATURAL AND APPLIED SCIENCES UNIVERSITY OF ÇUKUROVA Supervisor: Assoc. Prof. Dr. Recep YURTAL Year: 2002, Pages: 132 Jury : Assoc. Prof. Dr. Recep YURTAL : Prof. Dr. M. Salih KTRKGÖZ : Prof. Dr. Ahmet YÛCEER The aim of flood frequency analysis is to predict the flood discharge for a known period in a flood event for planning and designing of reservior, river basins, bridge, dams, weirs, channels, water supply systems, culverts, etc. Two Methods are available for flood frequency analysis named as following: 1. At-Site flood frequency analysis 2. Regional flood frequency analysis In this study, regional flood frequency analysis applying to Seyhan and Ceyhan river basins is investigated as nondimensionalized, and different models for predicting flood discharge in the analysis are compared and tested. After dividing the Seyhan and Ceyhan river basin areas into sub-areas, Log Logistik, Log Pearson 3, Pearson 3, Wakeby, Log Boughton, Gumbel and Log Normal models were applied to those subareas by the means of spreadsheet programs for regional flood frequency analysis. At-Site flood frequency analysis was then made using the special package program prepared by the means of Fortran 77 for the local stations on the Ceyhan and Seyhan river basins. Kolmogorov-Simirnov, Cramer Von Mises and Chi2 tests were used to determine which flood frequency model produced the most accuracy results when applied to observed data. It was seen that regional flood frequency analysis produced more accurate results than that of at-site flood frequency analysis when applied to Seyhan and Ceyhan river basins. Key words : Flood Frequency Analysis, Probability Weighted Moments, Regional Flood Frequency Analysis. n