New River Llynfi Restoration Project

Thursday, January 30, 2020

Friday 20th December, 2019

Early in 2020 the Foundation will start a new project to restore habitat on the Llynfi, an upper Wye tributary that flows out of Llangorse Lake and enters the Wye at Glasbury. Tragically, the stream was hit by a severe pollution event in 2016 that wiped out most, if not all, the trout, grayling and juvenile salmon in its middle to lower reaches.

This isn't our first visit to the Llynfi sub-catchment. Some might remember one of its feeders, the Llynfi Dulas, for the old cars that were being used to shore up its eroding banks. In one of our first major projects in 1998 (WHIP) we removed and replaced them with more conventional river restoration methods – tree coppicing, revetments and a fence!

The Llynfi system became one of the most productive in the upper Wye catchment for salmonids, making the 2016 fish kill even more devastating. Since then the river has been recovering steadily, especially for trout and grayling.

Foundation staff pinning willow to the banks of the Llynfi in 2014 to prevent erosion. The image a the top of the page shows the same section of river one year later.

With the support of our partners Natural Resources Wales and Gwent Angling Society, we will be replacing old fences, putting up new ones and installing revetments where the river has been eroding excessively.

Earlier this December our Llynfi surveys took us past the site of a previous revetment that we installed in a badly eroded section of the stream in 2014. Willows from the river nearby were pinned into the bank and, importantly, a fence was erected to protect any new growth from grazing sheep. Five years later the structure has held, shored up the bank and provided fish that have recolonised the river since the pollution with important habitat and cover from predators (see image below).

We know these structures boost fish numbers. A similar revetment on the Garth Dulas (another Wye tributary) installed in 2011 during our ISAC project trebled juvenile salmon numbers almost immediately (see the ISAC end of project report here).

The Foundation is looking forward to starting work again in on this important tributary in the New Year. We will report more as the work is completed and on its results.

The revetment in December 2019, five years after installation. The willows have shored up the river bank and no provide important habitat and cover for fish.

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