The book is basically a hydraulic design aid for selection of diameter of pipe and/or deciding gradient of the pipeline to convey water from one place to the other economically. The novel feature of the book is that it highlights the power wasted in overcoming resistance due to friction offered by the surface of pipe in contact with the water. A judicious selection of right size of pipe diameter can save even up to 90% of the power used in transmission of water. The book also helps select appropriate gradient of the pipe line to convey a designed flow through pipe flowing under gravity conditions. It also gives details of flow parameters of partially-flowing circular conduits. This book will be useful to the students and the teachers of the engineering colleges and polytechnics. It will serve as most useful tool to the hydraulic system designers and practicing engineers as well.