Possibly the most spectacular feature of the River Castril is its source, deep in the heart of the Sierra de Castril Nature Reserve, where incredible springs appear as if by magic with surprising force. The source, where the waters are very cold, is really quite accessible since it can be reached via an easy path that starts at the Cortijo del Nacimiento, next to the hydroelectric power station.
A unique feature of the River Castril is that it is one of the most important trout streams in southern Spain. Where the water is excellent and the trout abundant, there will always be a natural predator that controls the population, as you can easily imagine. In this case it is the other star species inhabiting the nature reserve: the otter. The River Castril is one of the few rivers in Andalusia where this fluvial mammal is still present.