International Journal of Sciences: Basic and Applied Research (IJSBAR) ISSN 2307-4531 (Print & Online) http://gssrr.org/index.php?journal=JournalOfBasicAndApplied --------------------------------------------------------------------------------------------------------------------------- Determination of the Nonlinear Muskingum Model Coefficients Using Genetic Algorithm and Numerical Solution of the Continuity Equation Mohammad Shayannejad a , Nahid Akbari b , Kaveh Ostad Ali Askari c* a Associate Professor, Water Engineering Department, Isfahan University Of Technology, Isfahan, Iran b MSc student, Irrigation and Drainage engineering, Isfahan University of Technology, Isfahan, Iran c Department of Water Engineering, Faculty of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad , Isfahan , Iran a Email: shayannejad@cc.iut.ac.ir b Email: Akbari.n.92@gmail.com c Email: Kaveh.oaa2000@gmail.com Abstract The optimization method is an appropriate choice for determining optimal parameters in the Muskingum model, in order to increase the speed of computations; coefficients of this model have been computed optimally with assistance of the genetic algorithm. These coefficients were computed from the linear Muskingum and Muskingum-Cunge models using required data and the available relations. In order to evaluate efficiency of the procedure of optimizing coefficients of the nonlinear Muskingum model via the genetic algorithm method compared with the other two methods used for determining these coefficients, outflow hydrographs were computed using the optimal coefficients and solving the continuity equations according to the Runge-Kutta method order 4 and was compared with the two flood routing methods from the Muskingum and Muskingum- Cunge models as well. ----------------------------------------------------------------- * Corresponding author. Mob: +989122471430 E-mail address: Kaveh_oaa2001@yahoo.com 1