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. Situation The panorama shows the mouth of the Conwy Estuary from Deganwy Castle, the original defensive position of the area. However, problems with resupply in the event of siege and its destruction by Llywelyn ap Gruffudd, Prince of Wales in 1263 to prevent it falling into King Edward's hands, led to a new castle being built across the water in Conwy town. See also Conwy Valley Line (railway line) Rivers of Great Britain List of rivers of Europe References External links www.geograph.co.uk : photos of the River Conwy Rivers of Conwy County Borough Rivers of Snowdonia