“…Other comparisons have been conducted in the following cases: to identify the unit hydrograph of an urban basin, where the results were improved by using GP to obtain mathematical expressions that correct the model errors (Rabunal et al, 2007); to simulate rainfall-runoff processes, enabling GP techniques to provide a useful tool in solving problems in hydrology by means of a simple and explicit model (Aytek and Alp, 2008); to improve the reliability of hydrologic prediction, showing that GP models can be used to predict the model uncertainty (Parasuraman and Elshorbagy, 2008); and finally, to develop a flow prediction method, where the usefulness of a GP model as an effective algorithm to forecast the long-term discharges was demonstrated (Savic et al, 1999;Wang et al, 2009b). In addition to the aforementioned cases, the GP technique was also applied to real-time forecasting (Khu et al, 2001;Kisi and Shiri, 2011).…”