WHERE IS IT?: Draining the Brecon Beacons, this small river can be found entering the Usk valley at Sennybridge. OS Map 160.

PUT-INS/ TAKE-OUTS: We started in the village of Heol Senni, and finished in the village of Sennybridge, just after the confluence with the River Usk. Alternative start/ finish points are described below.


TIME NEEDED: 2 hours or more in low water.


WATER LEVEL INDICATORS: I paddled this when it read 3 on the gauge weir (see below); this was a bit low, more would be an improvement.

Chris C (Nov 2005)...'I did the Senni today twice, once in high flows the last run in very high flows. We got in under a road bridge; the first lane after Sennybridge on the Swansea road. This lets you get in round the corner of the most interesting bits. The first weir kicks up some nice play waves. The next weir/ drop becomes a 3/ 3+ rapid with big waves above and river wide hole which was sticky and held one guy for a bit. The rapid continued to the confluence with a few branches in the water to be careful of and some nice stoppers to play in. At the confluence to the Usk, the step kicks up a nice river wide play wave mainly green with a foamy pile to the left.'

GRADING: 2 with some Grade 3 rapids at the end.

MAJOR HAZARDS/ FALLS: Trees overhanging and also across the river. Barbed wire. One bridge with a plank blocking passage.

GENERAL DESCRIPTION: An easy and enjoyable trip. Grade 2 rapids are usually on bends in the first mile and a half. There are tree blockages and barbed wire fences on this section forcing portages, especially in high water. They aren't always obvious until you are close! There is a bridge at Brychgoed Farm which is partly blocked by planks. The next bridge (GR 928254) has the gauge weir below it, worth a look beforehand. After the weir the river is wider, some ledges provide pleasant play stoppers as you enter the village of Defynnog. You pass under the A4067. Below the river is trickier with a rocky weir to slide down and some falls/ rapids more significant than anything encountered upstream, maybe Grade 3 (finishing at the A4067 would avoid this). You now drop straight into in the River Usk in the centre of Sennybridge, and the stretch below is very enjoyable if you want to carry on.

OTHER NOTES: This was a bit scrapey at the level described. I recommend starting at the gauge weir to avoid most of the annoying obstructions; the river is more pretty below.

CONTRIBUTED BY: Heather Hutton, also Chris C.



Community Forum Comments on this Article
Re: Afon Senni -- jmmoxon
2018 Jan 15 09:07:59 PM
From the gauging weir down there are 3 trees right across (could paddle over them at 0.7, but not much lower, & above 0.8 would take you into the overhanging trees), then 2 snapped sheep fences (so open), followed by 2 complete fences, some more trees & the final sheep fence (near the church) is missing the left hand gate.

Trees gone below the gr3.

Re: Afon Senni -- Jon_Brown
2013 Nov 03 07:12:28 PM
Paddled final section today 03/11/2013) from Trephilip bridge down - the two trees below Gr3 ish fall are (no surprise) still there. We cut a few branches so that boats can be easily passed through on far river left. There is a nice rock ledge above and below tree that makes task simple at the level we ran it (Pont Hen Hafod was 0.46 metres at 04:30 so would have dropped). If much higher it may be possible to paddle over (but...).
Re: Afon Senni -- Hywel
2013 Oct 20 08:04:08 PM
Today (20/10/13) ran the section of the Senni described by Chris C. Shortly after the Gr 3/3 fall he described there is a tree across the whole river necessitating a portage (river left). Better not to run at all as there's a garden river left.
Re: Afon Senni -- Jon_Brown
2012 Oct 31 12:27:01 PM
We paddled the river in Feb 2011 it was at 0.70 on the gauge and going up a little. The bridge at Brychgoed Farm still has planks on its left 'arch' but even better the right arch has a telegraph pole attached to the bridge with lots of barbed wire (with more wrapped around for good measure). After that there are three river
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