Discussion of “Parameter Estimation of the Nonlinear Muskingum Flood-Routing Model Using a Hybrid Harmony Search Algorithm” by Halil Karahan, Gurhan Gurarslan, and Zong Woo Geem

Closure to “Parameter Estimation of Extended Nonlinear Muskingum Models with the Weed Optimization Algorithm” by Farzan Hamedi, Omid Bozorg-Haddad, Maryam Pazoki, Hamid-Reza Asgari, Mehran Parsa, and Hugo A. Loáiciga

“…The original paper estimated the Muskingum parameters by posing them as unknown variables. An initial condition is needed to estimate the parameter S 0 (the initial river-reach storage), and for this purpose, the initial condition I 0 ¼ O 0 is applied in the flood routing, in which I 0 denotes the initial reach inflow and O 0 denotes the initial calculated outflow (e.g., Chow 1959;Das 2007;Chu and Chang 2009;Orouji et al 2012;Easa 2013;Hamedi et al 2014;Bozorg-Haddad et al 2015a). The authors intended to improve the initial condition to produce a well-calibrated Muskingum model in the original paper.…”