The Afon Clywedog is an upland headwater tributary of the
River Severn
, name_etymology =
, image = SevernFromCastleCB.JPG
, image_size = 288
, image_caption = The river seen from Shrewsbury Castle
, map = RiverSevernMap.jpg
, map_size = 288
, map_c ...
in
Powys
Powys (; ) is a Local government in Wales#Principal areas, county and Preserved counties of Wales, preserved county in Wales. It is named after the Kingdom of Powys which was a Welsh succession of states, successor state, petty kingdom and princi ...
, Wales. It is approximately 29 km long and has its source on the flanks of
Plynlimon
Pumlumon (historically anglicised in various ways including ''Plynlimon,'' Plinlimon and Plinlimmon) is the highest point of the Cambrian Mountains in Wales (taking a restricted definition of the Cambrian Mountains, excluding Snowdonia, ...
and has its confluence with the Severn in
Llanidloes
Llanidloes () is a town and community on the A470 and B4518 roads in Powys, within the historic county boundaries of Montgomeryshire ( cy, Sir Drefaldwyn), Wales. The population in 2011 was 2,929, of whom 15% could speak Welsh. It is the third ...
. The annual rainfall over the catchment is between 1737 mm and 1836 mm.
River regulation
A large part of the upper catchment of the river is inundated by the
Clywedog reservoir
The Clywedog Reservoir ( cy, Llyn Clywedog) is a reservoir near Llanidloes, Wales on the head-waters of the River Severn. The construction of the reservoir was enabled by an Act of Parliament which asserted that ''"At certain times the flow of w ...
which stores water from the catchment, especially during the winter months, and releases it during periods of low flow to support the flow in the Severn so that drinking water may be abstracted downstream. The management rules also enable the reservoir to maintain the reservoir below maximum level during the winter so that there is capacity to absorb
flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
flows to reduce the impact of flooding further down the main river.
Hydrology in Practice. Shaw E
/ref> The Afon Clywedog thus has a highly regulated flow with relatively high flow in dry conditions and reduced flow in wetter weather.
See also
* Bryntail lead mine
Bryntail lead mine is a disused lead mine near Llanidloes in Powys, Wales. Sited on the Afon Clywedog and in the shadow on the Clywedog reservoir
The Clywedog Reservoir ( cy, Llyn Clywedog) is a reservoir near Llanidloes, Wales on the hea ...
* List of rivers in Wales
This is a list of rivers of Wales, organised geographically. It is taken anti-clockwise from the Dee Estuary to the M48 Bridge that separates the estuary of the River Wye from the River Severn.
Tributaries are listed down the page in an upstrea ...
References
External links
{{authority control
River regulation in Powys
Clywedog
Clywedog
1Clywedog