Reconnecting the rivers
We were amazed to find that our first walk over survey of the Wye (1995/6) showed that over half of all available spawning habitat for salmon and over three quarters of trout spawning habitat was barred to ascending fish. A combination of lack of thought and neglect had effectively reduced the size of the rivers' productive area by nearly half. Weirs and poorly designed crossing points were the main culprits but huge debris dams had also formed on an alarming number of tributaries, completely sealing off 100's of km of spawning and nursery habitat. For salmon this was disastrous and the main cause of their decline, particularly the loss of the Lugg and its tributaries in the 1980s.
A timber dam was found blocking the Sgithwen, an important upper Wye spawning tributary. The right hand photo shows the stream reopened by the Foundation after just a few hours work.
Populations of brown trout remained above the blockages but the larger main channel residents, which provided the bulk of the egg deposition, had been prevented from reaching the smaller tributaries which contained the ideal sized gravels. This meant that the annual dispersal of surplus 10-15cm fish downstream no longer occurred, leading to a collapse in the trout fishery too.
Between 1996 and 1997 the Foundation embarked on an ambitious and challenging programme to reopen the tributaries of the upper Wye. The experience of the Tweed, North Esk and elsewhere showed that this is the single most cost effective way of increasing fish populations. In total, this action reopened 132km of salmon and 330 km of trout spawning areas. The work took two years (including surveying) and remains the most cost effective project the Foundation has completed.
The lower weir on the Digedi before and after the Foundation built
a fish pass
After this initial effort the Foundation has continued opening or reopening streams and rivers elsewhere in the projects: WHIP , pHish , UP! , Leader+ , Lugg & Arrow, Radnor and ART/Defra. The current and historical situations are detailed on the maps below which show the extent of the Wye catchment upstream that was blocked to migrating fish in 1995. Click on the dates to the left of the map to see the current situation and the amount of river that will be open in 2015.
Red: Access barred to migrating fish by weirs, timber blockages etc
Black: Areas of the catchment that are permanently blocked - natural waterfalls,
Elan Valley Dams etc.
The Lugg and Arrow (the Wye's largest tributary) have numerous barriers built in the 18th and 19th century to control flooding and erosion. Even without adequate fish passage, up to 3,000 salmon redds were once recorded. However, in 1982 the Leominster Flood Alleviation Scheme sealed off the Lugg and the run dwindled to a few persistent pairs of salmon. This has now been partially corrected with a modern fish pass at Hampton Court (2003) and with two passes at Leominster 2004.
Fish passes on the River Lugg at Leominster, built by the EAW in 2004. Before these were completed migrating fish were unable to progress any further.
The next phase was to secure full access over the historic weirs and this will be completed by 2012.
River Arrow Fish Passes: at Glanarrow, Eardisland (left), built by the Foundation in 2008 and at Hunton weir, Titley.
An EA fish pass at Holgates weir on the River Lugg just downstream of Kingsland. The pass had become blocked with debris but after the EA modified it to WUF specifications (above right) it is open again and less likely to become blocked.
The Monnow was closed to salmon in 1917 when Osbaston weir was built to generate electricity for Monmouth. Skenfrith weir upstream was washed out by the floods of 2000. A project between EAW and the owner of the land at Osbaston resulted in an innovative scheme to create fish passage and generate electricity. The two Archimedes screws are "fish friendly".
Above left: the previously impassable Osbaston weir, prior to the hydropower (above right) and fish pass scheme (below left). A salmon passing through the fish pass (below right), completed by the EAW in August 2008.
In August 2011 EAW breached the left hand side of Kentchurch weir on the Monnow. Fish passage is now possible in all five of the main tributaries upstream. The remainder of the work consists of removing the rest of the structure and making good the surrounding area. The benefit to salmon, brown and sea trout will be enormous.
Milestones in improving Wye fish access:
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1996/7 Upper Wye Access Project.
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2003 pHish project - 7 fish passes.
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2003 Hampton Court fish Pass opened R Lugg by EA Wales.
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2004 Lugg Flood alleviation scheme fish passes (EA Wales).
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2006/8 Lugg and Arrow: 12 fish passes completed.
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2008 Osbaston Fish Pass (Monnow) and lower Arrow passes completed.
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2010 Four more fish passes completed on Arrow to take fish above Kington. Three Lugg fish passes modified by EAW below Kingsland.
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2011 EA Wales breaches the weir at Kentchurch, opening up a huge spawning area on the Monnow system as a result.
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2011 WUF makes further improvements to upper Lugg and Arrow access with 8 more fish passes.
USK
In 2004 we turned our attention to the Usk and found that while the river above Brecon is mainly unobstructed, the catchment from Brecon to Abergavenny is as bad as on the upper Wye in 1995 with every major tributary having at least one serious obstruction.
Our tour de force was the construction of a fish pass in 2006 on the Cynrig – a stream that collects its rainfall from the steep slopes at the top of the Brecon Beacons.
The Abercynrig fish pass, showing the weir (left) that obstructed migration and the completed fish pass (right), which has opened up approximately 7kms of salmon & trout nursery area.
