River Thaw
| River Thaw (Afon Ddawan) | |
| River | |
 The River Thaw south of Cowbridge
|
|
| Countries | United Kingdom, Wales |
|---|---|
| Region | South Wales |
| County | Vale of Glamorgan |
| Tributaries | |
| - left | Kenson River, Nant Tre-gof, Nant Aberthin |
| - right | Nant y Stepsau, Factory Brook |
| Cities | Cowbridge, Llanblethian, Aberthaw |
| Source | |
| - location | Southwest of Llanharry, Vale of Glamorgan, Vale of Glamorgan, Wales |
| - coordinates | 51°30′30″N 3°27′03″W / 51.5082°N 3.4509°W |
| Mouth | |
| - location | Bristol Channel |
| - coordinates | 51°22′58″N 3°23′46″W / 51.3828°N 3.3961°WCoordinates: 51°22′58″N 3°23′46″W / 51.3828°N 3.3961°W |
| Length | 20.0 km (12 mi) |
The River Thaw (Welsh: Afon Ddawan) (also Ddaw) is a river in the Vale of Glamorgan, south Wales. At 20 kilometres/12.4 miles, it is the longest river entirely in the Vale of Glamorgan.
Its source is in the hills just south of the M4 Motorway near Llanharry. It flows in a generally south-eastern direction through the town of Cowbridge, then turns southward and reaches the Bristol Channel at Breaksea Point, south of Aberthaw.
The river supports healthy populations of a variety of fish. However, several stretches of the river no longer support a European water vole population, despite having a once sizeable population. Unlike many rivers in south Wales, the Thaw was never subject to much pollution, except at its mouth which was diverted to feed the Aberthaw Power Station. In the last century, there has been a slight decline in the river's biodiversity. Its major tributary, the Kenson River, is polluted in its lower reaches due to agricultural run-off and effluents leaking from nearby quarries. The river is also a popular site for various kinds of recreation, accessible for much of its course, much of which is used for agriculture. There are many archaeological sites along the river. The river was once large enough for the villages and settlements along its banks to have access to shipping and thus the sea. Its estuary was once wider, but silting and impoundments have reduced its size considerably.
The river picks up many tributaries along its course, making its watershed the largest in the Vale of Glamorgan.
The Kenson River is by far the largest tributary of the river. It has a total length of 2 miles and is formed at the confluence of two other rivers, the Waycock and the Nant Llancarfan. It runs southwest through the village of Penmark and near Rhoose and Cardiff International Airport. The Kenson is also known for its good angling, and had many tributaries of its own. These include the River Waycock which is itself 9 kilometres long, and flows through Dyffryn and Penmark. It has many sources between Wenvoe and St Lythans, and meets the Nant Llancarfan at Penmark. The Nant Llancarfan rises at Bonvilston, flowing southward for 5 miles.
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Wikipedia