การทดสอบการแจกแจงความถี่สำหรับสภาพการไหลต่ำสุดในลุ่มน้ำยม กรณีพิจารณาการเปลี่ยนแปลงสภาพภูมิอากาศ

Abstract

This paper presents a method of Maximum-flow frequency analysis for Ping Wang Yom and Nan River Basin. Climate change that has occurred Causing global warming Affecting the changing conditions of the watershed and volume flow rate. Which is important in water management planning and hydraulics building design. The analysis of the original frequency distribution theory may not be suitable for the current peak flow conditions. Therefore, up-to-date information is used to test the appropriate frequency distribution theory with peak flow rate data. Using water stream data from representative stations with a data interval of at least 20 years and having total natural flow characteristics of 25 selected gauging stations were used in the analysis. Initially, a comparison test of goodness of fit (by the Chi-Square, Kolmogorov-Smirnov, and Least Square methods) was made between the Log-Pearson Type III, Three-Parameter Weibull, Three-Parameter Log-Normal, Two-Parameter Weibull, Two-Parameter Gamma and Gumbel distribution functions to identify the suitable type of distribution for low-flow analysis in the studied basins. The Gamma theory with the Maximum Likelihood parameter estimation was found to give best fit with the observed data. Has a more reasonable value than the previously used frequency distribution theory.

Keywords : Maximum-flow frequency, Test of Goodness of Fit