The International scale of White Water Rafting difficulty is rated from: Grade 1- (Easy) to Grade 6- (Unraftable). Most of the rivers in the UK are usually Grade 1-3 runs but can change depending upon water levels. International White Water Rafting destinations such as the river Zambezi, the Alps etc. typically run grades 4-5. All the river systems in the world are either fed by melting snow, glaciers or rain. In the UK rivers are predominantly rain fed systems, making rafting wales conditions unpredictable. If levels are too low for rafting you will get the option of Kayaking in sit on top kayaks on a suitable stretch of white water on the same river- see video below.