Cauldron Linn

In England we show measured level (and flow, where recorded) from the nearest Environment Agency station; in Scotland (SEPA) and Wales (NRW), the nearest station with level + trend. Either way it is a real sensor in the river, updated through the day — we name the station, how far away it is, and link to its source page. It is a reading from the nearest gauge, not necessarily the exact spot you swim.

Each gauging station publishes its own typical range. We compare the latest reading to that station's range — so "high" means above what is typical for that river at that point, not a one-size-fits-all threshold.

Rain in the catchment increases river levels and flow, sometimes hours or days after it falls. Heavy rain can also wash debris into the river and reduce clarity. Where there is no nearby gauge, recent rainfall is the best signal we can show.

Measured gauge data covers the UK — England (Environment Agency), Scotland (SEPA) and Wales (NRW). Outside the UK, or where no station is within range, we show recent rainfall (the best simple guide to river levels) and say so plainly — we do not estimate a flow figure.

Rising levels mean more water is entering than leaving — conditions may get more challenging. Stable levels are predictable. Falling levels usually mean improving conditions, but be aware of what caused the rise.

Weirs create dangerous recirculating currents that can trap even strong swimmers. Never swim near weirs — always give them a wide margin.