Model and prototype results for a sinuous two-stage river-channel design

A relocated length of the River Blackwater in Hampshire, UK, has been designed and constructed as a doubly-sinuous, two-stage channel. This has been established as a field test site with water level and discharge recording equipment for an ongoing analysis of its hydraulic and ecological performance. Preliminary hydraulic data, which were collected from the site, are analysed and compared with data from two hydraulic models which were built to the same design but at different scales. Results from the prototype, the 1/5, and 1/25 scale models are examined for scaling relationships and scale effects. The small-scale model was then reconstructed with a 2:1 vertical-scale exaggeration, and the results were assessed against the others. Methods for the selection of appropriate surface roughness for small-scale river models are discussed.