Geology and Geomorphology
The Conwy is bounded to the east by the rolling ancient mudstone hills of the Silurian period, the Migneint Moors. These acid rocks are generally covered in thin, often acid soils and for large parts of the upland areas the cover is of moor-grass — Mollinia spp and Erica communities. As a result the water entering the river tends to be acidic and often coloured brown with humic acids
To the west, the catchment is underlain by older Cambrian rocks which are harder and the landscape is, as a consequence, more dramatic with high craggy hills and mountains through which the river falls in cascades and waterfalls. Excellent examples of torrential river geomorphology can be seen at Conwy Falls and in the Lledr Gorge. The land to the East is highly forested with planted non-native conifers.
The western side of the valley is rich in lakes and reservoirs some of which provide drinking water supplies. The rocks are also rich in minerals and there are many abandoned mine sites where copper, lead and silver have been mined since Roman times.
The central river valley down-stream of Betws-y-Coed is relatively wide and fertile, and supports dairying and sheep rearing. In winter time these pastures are used to nurture the sheep brought down out of the mountains to avoid the worst of the winter weather.
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