This text is intended for a senior/graduate level course in hydrosystems. Students who take this course must have previously taken a course in hydrology and hydraulics. The term Hydraulics can also be used to describe different types of water projects. The scope of this text covers both of these definitions. The major focus of the text is to bring together the use of mathematical modelling with the use of hydrosystems for the analysis, design, operation and managment of water projects. To accomplish this goal, the authors present the basic principles of optimization, probability, and risk analysis and then apply these principles to the areas of water supply management and water excess management.