Area: 17.4 hectares.
Description and Reasons for Notification:
This is a new Geological Conservation Review site within Exmoor National Park.
The River Lyn occupies a catchment of 95 km2of gently sloping moorland on the west of Exmoor. The river was the scene of a unique rainfall sequence and associated flood event in August 1952, following a period of prolonged and heavy rainfall. The large volumes of water and sediment moved during these floods created a suite of geomorphological landforms which are still visible today. In the upper reaches of the catchment, at Cannon Hill, both erosional and depositional landforms are found. These include erosional slope scars and depositional boulder deposits. In the lower reaches of the catchment of the river flows through a gorge at Lynmouth, where a suite of large boulders now occupies the river bed. These boulders were deposited during the 1952 flood when the competency of the river was much greater and are testimony to the power and magnitude of the flood event. This site is therefore important in demonstrating the effects of high magnitude – low frequency flood events and their influence on the development of geomorphological systems and landforms.