The book is intended to present an up-to-date overview of the current network design procedures and develop basic guidelines to be followed in both the design and the redesign of water quality monitoring networks. The book treats the network design problem in a comprehensive and systematic framework, starting with objectives of monitoring and elaborating on various technical design features, e.g. selection of sampling sites, sampling frequencies, variables to be monitored, and sampling duration. The design procedures presented are those that the authors have recently applied in a number of national and international projects on the design and redesign of water quality monitoring networks. Planners, designers, scientists, and engineers who are involved in hydrometric network design will benefit from the in-depth approach assumed in this book. It will also be of interest to those working at research and data centers, international programs and organizations related to environmental monitoring. The book may also be used as a reference text in graduate courses of water resources and environmental engineering programs.