Conceptual flow model and changes with time at Braunton Burrows coastal dunes

Braunton Burrows supports a rainfed groundwater system with a water table that is mounded along an axis near and parallel to the eastern boundary of the Burrows, but trends westward towards the north of the system around the Golf Club. Annual water level fluctuations are up to 2 m. The long term recharge and discharge/abstraction estimate for the Burrows is 478.6 mm. Much of this drains to the foreshore at low tide on the west and towards the West Boundary Drain on the landward side in the east. Some groundwater is intercepted by drainage of fields north of Sandy Lane Car Park and at the Golf Course which also has an abstraction borehole in the sands. Deepening of the West Boundary Drain in 1983 affected water levels only in the immediate vicinity of the drain. Effective rainfall has declined by 5% since the mid 1960s. The 24 month moving average for rainfall at Bideford parallels the hydrographs, reflecting a rainfed system independent of significant outside influences. Since 2001 the water level has fallen although there has been considerable recovery during the period February to April 2007. In the long term, groundwater levels may be affected by a number of influences but decline in effective rainfall is the critical influence. Change in land cover is unlikely to be a significant influence on the water table. The historical data set is comprehensive and complements that for the Ainsdale National Nature Reserve on Merseyside. It is recommended that consideration be given to gathering some additional data to cover present uncertainties in order to develop a groundwater flow model for the Braunton aquifer. The model could be used to simulate climate change outcomes, and could enable management options for the dunes and associated wetlands which could be applicable to both Braunton Burrows and other coastal dunes in England and Wales.