River Conwy - Water Quality

Water Quality

The River Conwy is routinely monitored for quality by the Environment Agency. The river quality tends to be acidic in the headwaters with very low concentrations of the common anions and cations. Whilst conductivity rises as the river flows towards the sea, the overall organic quality remains very good despite some slight increases in ammonia due to diffuse agricultural inputs.

The Environment Agency also constantly monitors water levels in the valley, with a view to giving flood warnings. There are measuring stations at Betws-y-coed (Cwmlanerch), Llanrwst and Trefriw.

The Conwy is noted for its salmon and sea trout although increasing acidification in the second half of the 20th century, especially in the poorly buffered upland waters has significantly impacted upon their spawning success. The construction of an artificial fish pass in the 1990s to allow migratory salmonids access to the river above Conwy falls was intended to help mitigate the effects of acidification.

The Conwy Crossing, an immersed tube tunnel was built under the estuary during the late 1980s and early 1990s. It was opened by the Queen in October 1991. This resulted in the loss of some saltmarsh but also led to the creation of Conwy RSPB Reserve.

Since 2002 the valley has been overlooked by the turbines of the Moel Maelogan wind farm.