Water quality models that simulate chlorine decay are valuable tools for the management of chlorine residual. Such models are currently used for dosage optimization, chlorination facilities siting and prediction of critical locations where chlorine may decay to ineffective levels. Although many efforts have been made in the last decades (Rossman et al., 1994; Shang et al., 2008), the modeling of chlorine residuals is still complex, as it relies on the accuracy of hydraulic models to describe flows and flow velocities (Blokker et al., 2008; Pasha and Lansey, 2010) and on the adequacy of chlorine decay kinetic models (Fisher et al., 2011a). The nth order bulk decay kinetic model with respect to chlorine is described by the following equation: