Forecasts

Local

The Frome
When Frome Rodden EA gauge is at 1.0m the water level is just over the top of the jetty.
When the Tellisford EA gauge is at 1.6m the water is just flowing over the weir at Langham Farm. When the gauge is at 1.1m the level is around 0.1m below the crest and there is still a significant flow under the bridge.

Exmoor

The Exe
The Exe is at a good level for a group of improvers when the EA Thorverton Gauging Station (webcam here) reads between 0.6m and 0.8m. 0.4m will give a low run.

The Barle
The Barle is at a good level when the EA gauge at Brushford (Dulverton) is between 0.6m and 0.8m.  0.5m will give a low run.  Webcam at Dulverton Bridge (0.25m is low).

The East Lyn
Brendon EA gauge.  Watersmeet Web Cam. Green appears to be the minimum level to run the river. The gorge may still be possible with the level lower. For an idea of what to expect at each number on the gauge see here. Note the large picture does not currently update, right click a small picture and View Image.

Dartmoor

The Dart
A good level on the Dart for a group of improvers is when the water is level with the slab or ledge at Newbridge and this equates to around 0.7m or 0.8m on the EA gauge at Austins Bridge Buckfastleigh. 0.4m is a low run.  See also Dartcam at River Dart Country Park.
The West Dart EA gauge at Dunnabridge gives an indication of the level likely on the Upper Dart. The West Dart gauge is 30-45 mins upriver of Dartmeet and 4-6 hrs after the rain gauge reading at the Dartcom Weather Station (next to Powdermills near Princetown).  See also IsTheDartRunning?  The graph gives a prediction of rainfall and river level.

The Teign Fingle Bridge Web Cam. Clifford Bridge EA gauge.

The Tavy  Mary Tavy EA gauge. Denham EA gauge. Tavistock Town Bridge Web Cam. Note the web cam level doesn't appear to go below 25cm due to the proximity of the weir. Check the volume and colour of the water flowing over the weir.

The Erme Harford Bridge EA gauge.

See also Dartmoor River Levels and EA Gauges

Wales

The Usk
Usk Cam Brecon  The Usk is good to go between 1½ and 2.  From Sennybridge 1¼ is low and from Talybont 1 is low.
Trallong NRW gauge (Sennybridge).  Llandetty NRW gauge (Talybont).

The Ogmore  Bridgend NRW gauge

The Tawe Craig y Nos NRW gauge

Canolfan Tryweryn Water Release Information

Cardiff International White Water Park & Play - Pump Times and Booking

Other

Rainchasers river levels

Surf

North Devon
Magic Seaweed North Devon 
The surf can be affected by the swell, by the wind and by the state of the tide. Saunton is protected from Northerly winds. Putsborough is protected from Southerly winds and from the full power of most swells. Most beaches work best on a rising tide at around three quarters high. Croyde surprisingly works best at around low tide.

North Cornwall
Magic Seaweed Polzeath
Constantine Bay and Harlyn / Constantine Bay Surf Store