This study examines the hydrodynamic properties of river spawning fish nests (commonly referred to as redds). Many biological studies and inventories of brown trout (salmo trutta) and rainbow trout (Oncorhynchus mykiss) have been conducted which identify that redds are typically found in riffle and run morphologies of gravel bed streams. However, the site specific fluid and sedimentological properties of fish staging locations and nest persistence remain unknown.

Although many studies have investigated the spatial and statistical occurrence of redds in river systems, there has been little research into the fluid mechanics and hydraulic properties of these features. This study focuses on characterizing the discrete fluid properties and related river mechanics processes of redd location selection, development and persistence.