Cauldron Snout Cascade in Upper Teesdale is famous as England’s longest, largest and most impressive stairway of rapids. It is a mighty and breath-taking feature that impressive countless visitors every year. Today it is located in the Upper Teesdale National Nature Reserve just below the huge expanse of Cow Green Reservoir. This reservoir and its dam now regulate floodwater and prevent this set of cascades from displaying the awesome uncontrollable power of earlier times.