Management of water resources is one of the most challenging and interesting problems for the survival of the life. The demand of water is increasing in a tremendous way whereas the availability of water remains practically constant; therefore it becomes very important to study the hydrological system in a proper way. Forecasting of hydrological variables like, rainfall and runoff using past experiences is very helpful for the proper management of hydrological reservoirs as well as for warning of extreme flood or drought conditions to help to optimize the operations of systems. This book will give an introduction of Artificial Neural Networks and will be helpful to understand applications of Artificial Neural Networks in hydrology. This book also contains development of multiple linear regression models for the river stage discharge and comparison of developed multiple linear regression models with developed ANN models.