The Tryweryn is a river in North Wales. It starts from Llyn Tryweryn in the Snowdonia National Park and after 19km joins the river Dee at Bala. It is one of the main tributories of the Dee and has been dammed to form Llyn Celyn . Water is stored in winter when flows are high, and released over the summer to maintain the flow in the Dee (the Dee is used as the water supply for cities in North West England).
The Tryweryn is an important river for whitewater kayaking and rafting. The regular releases from Llyn Celyn in summer mean that kayak events and trips can be planned in advance, and commercial rafting can take place (most whitewater rivers in Wales rely on recent rain to have enough water for kayaking or rafting, and public access to other rivers is rare). The Welsh Canoe Association manage kayaking and rafting on the river, charging paddlers to canoe and running commercial raft trips. There is a cafe and campsite.
The natural whitewater rapids have been modified (boulders have been moved) to make them safer and to build playspots. The river is usually considered to be grade III. Usually between nine and twelve cumecs are released.
