GUIDE TO THE AFON GRWYNE FAWR
(Grwyne Fawr Reservoir to the Usk)
NAME OF RIVER: Afon Grwyne Fawr.
WHERE IS IT?: Joined by the Grwyne Fechan below the Lower Cwm bridge, this great little river has its water from the Black Mountains, topped up by the Grwyne Fawr reservoir. It joins the Usk below Crickhowell at Glangrwyney having passed under 'Dicky Valentine's Bridge on the A40.
From Abergavenny travel towards Crickhowell on A40 but when you get to Glangrwyne, turn off right Abergavenny side of the river and go up towards the Grwyne Fawr reservoir.
PUT-INS/ TAKE-OUTS: The river can be run from the car park just below reservoir. However the river will need to be in spate (6+ at the Llangenny weir) for this run. River levels can be assessed at the measuring weir in Llangenny. The river is paddleable when the gauge is at 4, albeit low. Anything over 5 and the river is fun to paddle. For the lower section - and probably the best paddling - put in at Lower Cym Bridge (GR245200) onto the Grwyne Fechan. Parking is best just before the bridge in the small 'layby'. In order not to block the road and maintain good relations with the farmer a MAXIMUM of one car is advised.
This is NOT a river for big groups.
The take out is either immediately under the bridge at Glangrwyney - access a path river left which leads up to the road and the layby- or continue on down to the Usk and Abergavenny. The small Community Centre car park in Glangrwyney can be used for parking but again it is stressed NOT for big groups.
APPROX LENGTH: From the Car park below the reservoir to the Glangrwyney bridge it is around 15 km. From Lower Cym Bridge it is approx 6 km.
TIME NEEDED: The lower section can be run in an hour providing too many trees are not down. From the top allow considerably more time as the river is tight and technical. Our last trip from the top took over four hours.
ACCESS HASSLES: here is no access agreement as far as I know, I have never had a problen getting on or off the river over the past five years BUT we have always paddled with a maximum of 5 boats. These small rivers cannot take big groups and neither can the local environment.
Tom Hodgkin...'It was fine when we did it. We also got out at the dangerous weir to inspect and an old lady came to chat with us (because we were on her land), and she didn't mind.'
WATER LEVEL INDICATORS: Llangenny Weir gives an accurate measurement of levels:
Below 4 - Low
5 - Medium levels, weir becomes mean and nasty
6 - A good paddling level, weir begins to growl
6+ - Fun fun fun - but serious, the weir becomes a death trap and some of the falls notch up to Grade 4ish.
Tom...'Needs to be paddled after substantial rain. We paddled it after 3 days continuous rain and it was brill and we paddled it again the next day (no rain) and it was **** because of hardly any rain. The more rain the better!!'
Conor O'Neill...'We paddled this yesterday (30/12/2002) after a few days of medium rain. The gauge on the weir was around 2.5 to 3. This was a fine relatively easy paddle, grade 2-3, certainly worth doing. This would be a good trip for intermediate paddlers, who already know how to break out! Some play waves. A few trees, but nothing too sudden at this level. The weir was OK to punch straight through at this level. It did back-loop one paddler, and it took us a few minutes to extract the boat, but the person swam out with no problem at all.'
GRADING: Overall its a good continuous Grade 3 at medium levels. In high water levels some of the falls in the upper section can get up to at least 3+ and Pendarren Falls becomes 3+/ 4.
MAJOR HAZARDS/ FALLS: The weir at Llangenny is the major hazard. It is characterised by the initial measuring weir which forms a lethal towback in high water - rather like Strangerthwaite on the Lune - Below the measuring weir is another broken weir with a double drop. This can be run either river left - easy route - or by taking the lune of the old fish ladder - much harder. In good flows a grabby stopper forms below, several good paddlers have lost their mounts in this! It is important that paddlers remember where the weir is, particularly in high flows. Soon after passing under the bridge at Llangenny the river picks up speed and passes an open field on river right. This is the get out before the weir and in high flows can be awkward. The weir can be inspected from the road.
Other hazards are fallen trees - three at the last count below the Lower Cym Porth put in - and several in the upper section.
Tom Hodgkin...'After a left hand bend with a man made cliff on the right, there is a fall. This is no problem but you then have to get out on the river left because there is a large tree smack bang across the river. There is no way round, just over in high water. It is very difficult to portage when you can see it so get out just below the fall. Once you see it you'll know what I mean. There are few large eddies so portaging is a struggle.'
Nathan Ball (17/02/03)...'The tree by the footbridge at Pendarren Falls is no longer there we assume it has been removed now!'
The largest fall is Pendarren Falls, name taken from the outdoor pursuits centre on river left. Recent roadworks have drastically altered the run in to the falls. A man made construction of large rocks etc on river right now gives ample warning of the falls ahead. Run river left for the easier route - double drop - or river right for the more technical line. In high water either line will go but beware the stopper river right. The road alterations have straightened out the river bed and altered the characteristics of the fall, in high flows it can get a little mean and nasty.
Near the get out there is a rope across the river that can be missed! Its been there for 4 years now so deserves a mention.
GENERAL DESCRIPTION: From the put in below the car park the river is a typical mountain stream, fast, tight and with some technical drops. These become more serious in spate. Strainers and fallen trees round off the upper section. The lower section from Lower Cym Bridge is characterised by grade 2/3 drops and shoots with the odd tree for good measure. Pendarren Falls is above Llangenny and can be inspected by exiting river left. The run into Llangenny is particularly good in high water, known by local paddlers as the 'Town Section' is provides a roller coaster of wave trains, weirs and drops. A short distance below Llangenny bridge is the weir. Paddlers should note that as soon as the wooden house on river right is spotted it is time to think about finding an eddy. The weir is only metres away. Below the weir the river continues down to a small bridge where a good playwave can be found- it washes out in high water though. The river now loses its magic and the drift down to the get out is an opportunity to decide whether to continue on down the Usk or not.
OTHER NOTES: Tom Hodgkin...'Absolutely fab. grade 3 roller coaster with shoots and drops. Few eddies so only groups of 3 and less.'
Mike Kelly...(Jan '02) 'The lower weir at Llangenny has a particularly nasty anti-scouring device. It has an arrangement of metal prongs - rather like down-turned pitch forks which the stopper flushes objects under - like a metal undercut. It can hold large objects firmly and has been the site of local drownings - not paddlers just locals but still of some consequence! Mal Price had a very unpleasant time in here and was pulled out - just by MD. Of use maybe to some - the flat field mentioned in the guide on river right as you approach the weirs at Llangenny is sometimes used for rough camping - knock on the adjacent farm - he'll do anything for a few bob!'
Anonymous...(28/01/02) 'I paddled the Grwyne Fawr from Lower Cym bridge too this weekend. Instead of getting on at the bridge we put on about 300 metres upstream, gaining access using the public footpath that runs across the fields on the upstream side of the bridge. This is a nice grade 3 start to the river, but you are into it from the word go and the trees are a nuisance but bearable. Has anyone paddled this tributary further upstream? It looks as though it would be a good technical run in high flows. The three trees across the river are still there, although the first can be run on river left with care, but about 50 metres downstream the second tree has formed a wicked looking strainer which will kill. We saw no sign of the tree which is supposed to lurk below Pendarren Falls. It may have been removed by the roadworkers.'
The EA on-line gauge was 0.38 which again matched the gauging marker at Llangenny weir. At this level is was Grade 2+/3 but a really enjoyable paddle for a small group.
The strand of barbed wire was still in place about 100m below Cwm Bridge get in, our leader exited to hold it up for the rest of us to duck underneath, but this would be an issue in higher water. (It would be easy to start the paddle just below this hazard if in doubt)
The tree mentioned by Stewart was passable river right with a little effort, but it might be sensible of the group to exit above and put on some safety.
The first step of Llangenny weir was shootable at this level, but the visible presence of the rebar spikes in the anti-scour lip again suggests that putting on safety from the bank is a wise precaution.
Despite being very polite and gentle reasoning she would have have none of it. Being quite late we opted for the pub instead of the long walk uphill.
I have found the Millbrook webcam , but there is not enough back data to know what the level was on Nov 25th.
The river was certainly high, but perhaps not as high as the 0.88 in September 2012.
The tow back on the Llangenny weir was at least 2 boat lengths, but those that paddled the bottom section put in just below this top weir and ran all the other drops directly below this.
The section from Cwm Bridge down was certainly challenging on the day. Some of our group compared it to an Alpine river with very fast current, several small must-make eddies, drops that had to be read on the fly and other similarities.
The instructions from our river leader were : when in doubt keep in the middle , and above all stay upright.
As above, I would love to do this again at a more "normal" level.