GCR block - Fluvial Geomorphology of Wales (FLU-GME-WL)

Fluvial Geomorphology of Wales

Block Description

UK map showing distribution of GCR sites of GCR block FLU-GME-WL
Distribution of GCR sites of GCR block Fluvial Geomorphology of Wales

A general introduction to British fluvial geomorphology is provided under FLU-GME-EG.

Fluvial systems in Wales have an extended evolutionary history of considerable interest, including, in particular, phases of rejuvenation and of glaciation; together, such phases have produced a landscape mixture of waterfalls, gorges, plateau uplands and flat-bottomed valley troughs. Present-day fluvial processes acting in Wales create a considerable variety of river types, ranging from upland source area streams, active boulder-bed channels, meandering and braided reaches, through to highly sinuous channels and stable lowland rivers.

The impacts of afforestation, land drainage and improvement, and river channelization, are modifying fluvial features in the landscape to an increasing extent.

The long-term geomorphological development of the Welsh landscape has been subjected to many different interpretations. In particular, the various plateau levels have been viewed as the product of either fluvial or marine planation at time periods ranging from the Devonian Period to the Quaternary Period. Some may have been exhumed from beneath a Mesozoic cover. In recent years this situation has been somewhat modified both in the light of plate tectonic models (creating a better understanding of the effects of the widening of the North Atlantic and the development of the faulted Welsh massif in a trailing plate margin environment, for example) and also as a result of new and offshore evidence from boreholes such as that at Mochras, Gwynedd, and other land-based sites, and from exploration work in the Irish Sea. These, like the reinterpretation of weathering products fragmentarily preserved, tend to emphasise the Tertiary reduction of landscape features to low-relief surfaces, but also the importance of Neogene faulting and then relative uplift of the Welsh uplands.

Quaternary glaciation added trough-like valleys and a widespread (if often thin) veneer of glacial sediments to the region. Fluvial processes are strongly conditioned by prior glacial activity. During the most recent ice-sheet glaciation, valleys were partially infilled with sediments that present rivers are currently removing. In some places, valleys may also be largely filled with glacial sediment, such that newer gorge sections have been excavated in bedrock to bypass them.

In the Holocene Epoch, the landscape has been evolving under fluctuating climatic and human influences; involving, for example, the development of a forest cover followed by its removal, and the development of upland and lowland peat deposits over the past several thousand years.


Volume Introduction

Fluvial Geomorphology of Wales


Site List

Your selection found 19 GCR sites. Sites are sorted alphabetically by country, local authority and then by site name -
CodeNameCountryLocal AuthorityGrid RefGCR Site Account
2544Afon LlugwyWalesCONWY AND DENBIGHSHIRESH764577Not available
2541Dee (Rhewl Section)WalesCONWY AND DENBIGHSHIRESJ182425Not available
2537River Wye at LancautWalesGloucestershireST532965Not available
2540AberglaslynWalesGWYNEDDSH595458Not available
2545Afon CynfalWalesGWYNEDDSH701413Not available
2538Afon DyfiWalesGWYNEDDSH860139Not available
2577Afon ElanWalesPOWYSSN865746Not available
2578Afon Mellte and Afon HepsteWalesPOWYSSN931133Not available
2548Afon Rhaedr at Pistyll RhaeadrWalesPOWYSSJ068297Not available
2547Afon TwymynWalesPOWYSSN869955Not available
2546Afon VyrnwyWalesPOWYSSJ250207Not available
2539River Severn confluence of Vrrnwy and SevernWalesPOWYSSJ269127Not available
2536Upper River Severn (Dolwen-Caersws-Penstrowed)WalesPOWYSSN996850Not available
2543Afon RheidolWalesSOUTH WEST WALESSN650800Not available
2549Afon Teifi at CenarthWalesSOUTH WEST WALESSN269416Not available
2551Afon Teifi at Cors CaronWalesSOUTH WEST WALESSN684627Not available
2542Afon YstwythWalesSOUTH WEST WALESSN702718Not available
2517Black Mountain scarpWalesSOUTH WEST WALESSN810220Not available
2550Maesnant (Plynlimon)WalesSOUTH WEST WALESSN785872Not available
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