Several statistical methods are being widely used for different hydrological, hydraulic and water quality studies. Based on different statistical methods, some researchers have developed statistical models, which are used for forecasting. Recently, a new non-linear technique named Artificial Neural Networks (ANN) is also emerged. ANN can establish non-linear relationships with input and output variables. This session will cover following topics: Statistical modelling of Rainfall; Statistical modelling of Runoff; Statistical methods for catchment water quality estimations; Statistical methods for river/stream water quality estimations; Statistical methods for reservoir water quality simulations; Decision Support Tools based on statistical methods; ANN for rainfall forecasting; ANN for water distribution system studies; and ANN for pollution transport and water quality studies.