A rigorous graduate-level treatment of river hydraulics and sediment transport, covering flow resistance, bedforms, channel stability, and the physical mechanics that govern river behavior.
Pierre Julien's River Mechanics is the graduate-level textbook that sits next to Fluvial Processes on the river-physics shelf. Where Leopold and Wolman gave you the broad framework and the historical case studies, Julien gives you the equations and the rigorous hydraulics. Flow resistance. Bedform regimes. Sediment transport. Channel stability. Shear stress distribution. If you want to reason quantitatively about what's happening in a rapid, or why a bend is migrating in the direction it's migrating, or how a gravel bar responds to a specific flood event, this is where the math lives.
I'll be honest: this book is not leisure reading. It's a reference, and for most river people it will be, at best, a book you dip into when a specific question comes up that Hendriks or Leopold can't fully answer. The notation is rigorous. The derivations are not simplified. If you don't have a year of calculus and some basic fluid dynamics under you, whole chapters are going to be slow going. That's fine. The book wasn't written for river runners. It was written for graduate students in hydraulic engineering.
But here is why I have it on the DM shelf anyway. There are moments — usually at a scouting bend, usually with somebody who knows more than you about what the rapid is doing — when the conversation gets technical. Why does the hydraulic at Big Drop 3 have the shape it has. Why does the sediment pulse from a specific tributary rearrange the bed thirty miles downstream of the confluence. Why does a reservoir release produce a specific clearing of the channel below the dam. These questions have answers, and Julien is where the answers are laid out in their formal form. Being able to point to a chapter and say, the math is in here — that matters.
The book is also quietly elegant in places. Julien has an eye for the specific physical intuitions that make a complex equation make sense. His treatment of why meanders form the way they form is beautiful, in a technical way. His chapter on sediment transport has the clearest single derivation of the Einstein approach I've ever read. If you are the kind of reader who likes to see the physics of a river properly formalized — not mystified, not hand-waved — this book will scratch that itch.
Keep it on the shelf as a reference. When somebody on the crew has a graduate degree in anything water-adjacent, pull it out at camp and have the conversation. You won't read it cover to cover, and that's fine. It's doing its job by being available, and by being correct when you need it to be.
