The high ground forms the catchment area for numerous rivers and streams.
There are about 483 km (300 mi) of named rivers on Exmoor.
The River Exe, after which Exmoor is named, rises at Exe Head near the village of Simonsbath, close to the Bristol Channel coast, but flows more or less directly due south, so that most of its length lies in Devon.
It reaches the sea at a substantial ria (estuary) on the south (English Channel) coast of Devon.
It has several tributaries which arise on Exmoor.
The River Barle runs from northern Exmoor to join the River Exe at Exebridge, Devon.
The river and the Barle Valley are both designated as biological Sites of Special Scientific Interest.
Another tributary, the River Haddeo, flows from the Wimbleball Lake.

Most other rivers arising on Exmoor flow north to the Bristol Channel.
These include the River Heddon, which runs along the western edges of Exmoor, reaching the North Devon coast at Heddon's Mouth, and the East and West Lyn rivers, which meet at Lynmouth.
Hoar Oak Water is a moorland tributary of the East Lyn River, the confluence being at Watersmeet.
The River Horner, which is also known as Horner Water, rises near Luccombe and flows into Porlock Bay near Hurlstone Point.
The River Mole arises on the south-western flanks of Exmoor and is the major tributary of the River Taw, which itself flows northward from Dartmoor.
Badgworthy Water is one of the small rivers running north to the coast and is associated with the Lorna Doone legends.
The high ground forms the catchment area for numerous rivers and streams. There are about 483 km (300 mi) of named rivers on Exmoor. The River Exe, after which Exmoor is named, rises at Exe Head near the village of Simonsbath, close to the Bristol Channel coast, but flows more or less directly due south, so that most of its length lies in Devon. It reaches the sea at a substantial ria (estuary) on the south (English Channel) coast of Devon. It has several tributaries which arise on Exmoor. The River Barle runs from northern Exmoor to join the River Exe at Exebridge, Devon. The river and the Barle Valley are both designated as biological Sites of Special Scientific Interest. Another tributary, the River Haddeo, flows from the Wimbleball Lake.
Most other rivers arising on Exmoor flow north to the Bristol Channel. These include the River Heddon, which runs along the western edges of Exmoor, reaching the North Devon coast at Heddon's Mouth, and the East and West Lyn rivers, which meet at Lynmouth. Hoar Oak Water is a moorland tributary of the East Lyn River, the confluence being at Watersmeet. The River Horner, which is also known as Horner Water, rises near Luccombe and flows into Porlock Bay near Hurlstone Point. The River Mole arises on the south-western flanks of Exmoor and is the major tributary of the River Taw, which itself flows northward from Dartmoor. Badgworthy Water is one of the small rivers running north to the coast and is associated with the Lorna Doone legends.
Exmoor