The River Avill rises on the eastern slopes of Dunkery Beacon and flows north through Timberscombe before joining the Bristol Channel at Dunster, where there was once a harbour.
'The purple-headed mountain, the river running by,' in the hymn 'All Things Bright and Beautiful' is said to be the River Avill running past Grabbist Hill in Dunster. The hymn may have been inspired by a verse from Coleridge's 'Ancient Mariner': 'He prayeth best, who loveth best All things great and small; For the dear God who loveth us, He made and loveth all.'
In February the Avill Valley becomes 'Snowdrop Valley'. An area of the valley not normally open ot the public is carpeted with snowdrops and the area opened up for people to enjoy. A park and ride service operates from Wheddon Cross whilst leaflets give details of local walking routes, which are very popular, if a little muddy, at this time of year.