The uncertainty in rainfall-runoff modeling predictions has become a topic of recent key interest. In this book, the uncertainty problem is approached by use of stochastic integral equations. Various aspects of the rainfall-runoff modeling process are scrutinized by use of probabilistic models, such that when combined, a stochastic integral equation results. Uncertainty in single even runoff estimates, as well as return frequency event outcomes are analyzed. Use of example problems demonstrate the application of stochastic integral equations in addition to explaining the underlying concepts. Computer program source code is also provided which can be used to solve both theoretical and real-world problems. The generous supply of chapter problems enables the book to be used as an applied textbook in stochastic integrals.