2020 UK River Prize

UK River Prize > 2020 UK River Prize

Finalists Announced!

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Congratulations to the winner of the 2020 River Prize:

Reach scale - Allt Lorgy

Catchment scale - Test & Itchen

 
2020 Finalists

Afon Merin, Ceridigion, Wales

The Afon Merin is one of the principal tributaries of the Rheidol system, flowing from its upland SSSI catchment, through NRW managed Welsh Government estate Myherin woodland and onwards into the Rheidol Valley. A 3km section provided landscape scale intervention opportunities to "kick-start" natural processes to benefit biodiversity, water quality and quantity, and carbon sequestration.

Historical maps showed a more dynamic river system prior to agriculture, conifer afforestation and land drainage in the catchment. The river had cut down into its bed, severing it from its floodplain on all but extreme events. Gravels had been scoured out of large areas of the watercourse leaving a cobble substrate sub-optimal for spawning salmonids. Significant lengths of the river were also dry during the extended dry spell in summer of 2018. The project commenced in early 2018 with felling of conifer, ditch blocking and instream structures to wet up the site and re-link the river to the floodplain and then the installation of 15 leaky dams and scrapes.

Water immediately started to spill out of bank picking up a network of relict channels within the floodplain. Subsequent high flow events have seen gravel depositing instream and as shoals, more dynamic flow patterns and a complex of side channels, permanent and temporary pond features. Total project cost including felling and installation of dams and scrapes was approximately £30,000.

 

 

 

 

Allt Lorgy, Highlands, Scotland

The Allt Lorgy is a typical upland spate burn that, in the late 1980s, was significantly managed for agricultural purposes (e.g. artificial embankments, rock bank revetments and in-channel boulder grade control).

The project is based on restoring the morphology and associated habitats of a 1km section of river and its adjoining floodplain. It has re-established the fundamental physical processes that drive the evolution of the river’s form and the associated benefits for instream, riparian and floodplain ecology. Rather than designing a specific channel configuration, the approach aimed to kick start natural processes such that the river re-establishes a natural equilibrium state with increased physical diversity and improved channel floodplain connection.

This involved the removal of artificial constraints (associated with past engineering works) that had simplified the watercourse to a straightened single thread form. Over 250m length of artificial embankments were removed, liberating >900m3 of material. In stream boulders were replaced with large wood structures. Additional wood structures were introduced at key locations and some of the embankment extracted gravel was used for ‘gravel augmentation’.

 

 

This work has now resulted in a self-sustaining system; enhanced lateral channel migration has begun the natural recruitment of riparian trees into the watercourse which further invigorates the dynamic change. Seven years later and after a number of high flow events, significant evolution of the site has occurred. In effect, the ‘circle of restoration’ has been closed, providing a sustainably evolving river environment. The majority of the funding was provided by the Water Environment Fund (SEPA) and Cairngorms National Park Authority (CNPA).

 

Rivers Test & Itchen, Hampshire, England

The Test and Itchen River Restoration Strategy is a long-term project being carried out on these two world-renowned SSSI chalk streams in Hampshire. However, both the SSSI’s are in unfavourable condition from historical modifications to the physical structure of the channel, the banks and the riparian zone. The aim of the T&I Strategy is to appraise the geomorphological condition of the rivers, identifying the condition of the rivers in relation to their ‘natural benchmark’ and then to restore the SSSIs and bring them into favourable condition.

The focus of all restoration projects within the T&I Strategy is to ensure the condition of the habitat rather than the preservation of the species directly, with the principle being that good chalk stream habitat is more likely to support characteristic flora and fauna. Although the Strategy is primarily aimed at in-river characteristics, it’s also recognised that land management adjacent to the rivers has the potential to affect the quality of the in-river habitat and has been given due consideration to this throughout the project. To date the strategy has used 20,000 tonnes of gravel to carry out bed raising on both rivers at various locations - reversing the legacy of dredging. Slow flowing sections with no chalk stream characteristics have been transformed with increased velocities, better Ranunculus (water crowfoot) growth, improved invertebrate communities and spawning of salmonid fish. The evidence of how successful these improvements have been, is seen from surveys by Southampton University.

The T&I Strategy was first initiated in 2010, with the main work starting in 2012, and it will need to continue over the next 20-30 years.

 

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Thank you to the 2020 Partners
 
 

**Partner opportunities for the 2020 UK River Prize are now available**

 

Find out more about the UK River Prize and previous winners >>>