“…Since the "universal approximator demonstration" at the end of the 1980's (Cybenko, 1989;Hornik et al, 1989;Irie and Miyake, 1988), artificial neural networks (ANN) have probably become the most typical machine learning algorithm and have been used in many different fields like physics, chemistry, medicine, ecology and hydrology (Cote et al, 1995;Faraggi and Simon, 1995;Kralisch et al, 2003;Lek et al, 1999;Lischeid, 2001;Smits et al, 1992;Suen and Eheart, 2003;Telszewski et al, 2009). Artificial Neural Networks have been widely used to model complex nonlinear relationships, particularly when the functional form of the relations between the variables involved is unknown.…”