Jean-Luc Demaret G
« A perfect family day on the Semois. The welcome at Kayak Semois Ardenne is warm, the equipment is spotless (the kayaks are modern and clean), and the free shuttle system is superbly organised. A must-visit in the Ardennes! »
The Semois is a deeply incised forest river that winds for nearly 200 kilometres through the National Park of the Semois Valley, from Chiny to Bohan before joining the Meuse. Its beech-lined meanders, steep slopes and alder riverbank woodland make it a true biodiversity corridor. Paddling down the Semois by kayak means crossing this setting at water level, at the speed of the current and in the silence of the paddle — the best seat for observing the life of the river.
Let us be honest from the start: a descent is not a safari. Most of the valley's animals are discreet, nocturnal or wary. What you mostly observe are silhouettes and signs — a heron taking off, a kingfisher's flash of blue, a trunk gnawed by a beaver. That is precisely what makes each encounter precious. Here, species by species and season by season, is what you really have a chance of crossing paths with.
The river birds, the real stars
These are the most visible residents seen from a kayak. Four or five species accompany almost every descent, and the National Park of the Semois Valley even devotes an educational trail to them at Chiny.
Grey heron Ardea cinerea
A motionless sentinel of the shallows, probably the easiest bird to spot: it lifts off heavily as you approach, to settle again a little further on.
A motionless sentinel of the shallows, probably the easiest bird to spot: it lifts off heavily as you approach, to settle again a little further on.
Kingfisher Alcedo atthis
A flash of blue and orange darting just above the water. Watch for it perched on a branch above a calm pool, especially between Chiny and Bouillon.
A flash of blue and orange darting just above the water. Watch for it perched on a branch above a calm pool, especially between Chiny and Bouillon.
White-throated dipper Cinclus cinclus
Recognisable by its white breast, perched on a rock in mid-current. Able to walk underwater, it is a sign of good-quality water.
Recognisable by its white breast, perched on a rock in mid-current. Able to walk underwater, it is a sign of good-quality water.
Grey wagtail Motacilla cinerea
A small grey-and-yellow passerine with a long tail, hopping from pebble to pebble while constantly bobbing its tail.
A small grey-and-yellow passerine with a long tail, hopping from pebble to pebble while constantly bobbing its tail.
Mallard Anas platyrhynchos
The most common water bird; in spring, you will often come across a female followed by her brood on the calm stretches.
The most common water bird; in spring, you will often come across a female followed by her brood on the calm stretches.
Rare and chance encounters
Some species frequent the valley without ever giving themselves up easily. The black stork (Ciconia nigra), a wary guest of the great Ardennes forests, comes to feed in the streams here: with a great deal of luck, you might glimpse it in flight above the wooded slopes — a rare encounter that you must never try to provoke or follow. In winter, outside the descent season, the great egret (Ardea alba) and the goosander (Mergus merganser), both expanding in Wallonia, may appear occasionally.
Beneath the surface: the fish
The Semois is a renowned trout river, whose cool, oxygen-rich waters upstream shelter a fine array of fish. Be warned, however: "the Semois shelters" does not mean "you will see". Most fish remain invisible from the kayak — only the surface shoals truly let themselves be glimpsed in the clear water of the shallows.
The emblematic fish
The brown trout (Salmo trutta fario) reigns over the Semois, whose coolness makes it a trout river managed for angling, notably in the blue zone of Vresse-sur-Semois. Shy, it gives itself away mainly through a few rises at the surface at dusk.
The fish you can actually see
In the transparent water of the shallows, the tight shoals of minnows (Phoxinus phoxinus) are among the few fish you really observe from the kayak. On the sunlit flats downstream, the silvery chub (Squalius cephalus) scatter as the boat passes. Lurking under the stones, the bullhead (Cottus gobio) goes unnoticed but plays a valuable role: its presence, like that of the minnow, attests to cool, good-quality water.
The discreet mammals
The beaver, a star revealed by its signs
The European beaver (Castor fiber) has returned naturally to Wallonia and is now well established on the Semois, particularly along the wooded stretches between Alle, Membre and Bohan. Strictly protected, it is a nocturnal animal: from the kayak, you sense it through its signs rather than the animal itself.
Learning to read the beaver's tracks
- Trunks gnawed into a "pencil point" at the base, with fresh chips on the ground;
- Slides: muddy chutes running down the bank to the water;
- Lodges of branches and mud, with an underwater entrance, and sometimes small dams.
Early morning or late in the day offer the best chances. You never approach a lodge or a burrow: they are protected by law.
The otter: presence suggested, observation almost impossible
The presence of the European otter (Lutra lutra) is suggested by environmental DNA analysis in certain Walloon catchments since 2022, but it has not been confirmed by camera trap and its location remains unknown. This extremely discreet, nocturnal carnivore is practically never visible. The DEMNA is clear: most of the "otters" reported are in fact misidentified beavers, coypu or muskrats. Remember: the beaver gnaws wood and builds; the otter, a fish-eater, gnaws nothing and builds nothing.
The bats at dusk
On a late-afternoon descent, as night falls, Daubenton's bat (Myotis daubentonii) — the bat most closely tied to Walloon rivers — hunts just above the water with its characteristic skimming flight, catching insects from the surface of the calm stretches.
The dragonflies of summer
From May to September, the calopteryx damselflies are among the most spectacular and reliable insects to observe. The banded demoiselle (Calopteryx splendens), with its metallic blue body and dark patch on the wing, flutters above the sunlit sections. More demanding, the beautiful demoiselle (Calopteryx virgo), with wings that are almost entirely blue-black, favours cool, shaded banks — its presence is a good indicator of well-oxygenated water. On the forest tributaries, you can watch for the large golden-ringed dragonfly (Cordulegaster boltonii), black striped with yellow. In short, the dragonfly is an excellent thermometer of the river's health.
The forest and the flora seen from the water
From the kayak, the eye naturally rises from the banks towards the slopes. The valley displays a characteristic vegetation zonation. At water level, the riverbank woodland of common alders (Alnus glutinosa) and ash plunges its roots into the current and stabilises the banks. On the slopes, the oak-hornbeam woods and above all the beech woods (Fagus sylvatica) clothe the hillsides: tender green in spring, they dress the valley in copper and gold in October. In the hollows of the cool combes and scree hides one of the rarest habitats of the valley, the ravine maple wood (sycamore maple, ash, elm, lime), carpeted with ferns including the evergreen hart's-tongue.
In spring, before the canopy closes over, the cool undergrowth can be covered with wild garlic and the sunlit banks blaze with the yellow of common broom. Between the villages, the valley bottoms open out onto hay meadows and tall-herb fringe communities with their high flowering grasses — habitats recognised under Natura 2000. Downstream, the alluvial floodplain of Bohan-Membre, managed as a nature reserve by Ardenne & Gaume, unfolds a wet mosaic of reed beds, sedge beds and swamp woodland.
A cultivated heritage: Semois tobacco
The Semois tobacco is not a wild plant but an agricultural and scenic heritage. Cultivated in the valley since the 18th century, it owes its renowned aroma to the valley-bottom microclimate; you can still spot the characteristic tobacco-drying sheds in the villages. Its know-how has been recognised as Intangible Heritage of the Wallonia-Brussels Federation since 2024.
When to observe? The valley's calendar
| Season | To observe as a priority |
|---|---|
| Spring (Apr.–June) | Nesting birds and birdsong, flowering undergrowth (wild garlic), broom in flower, the first dragonflies, the tender green leafing of the beeches. |
| Summer (July–Aug.) | Calopteryx in numbers, hay meadows and tall-herb communities in flower, bats at dusk on evening descents. Heavier footfall: favour early morning. |
| Autumn (Sept.–Oct.) | The coppery blaze of the hillside beech woods — the greatest scenic spectacle of the descent — and a calmer, more solitary river. |
The Semois, good-quality water… but fragile
No need to brandish a numerical ranking: the best proof of the Semois's health is its bio-indicator species, demanding of cool, oxygen-rich water — the white-throated dipper, the bullhead, the minnow and the beautiful demoiselle. Their presence says more than any table. The river nevertheless remains vulnerable: localised pollution, increasingly marked low-water periods and summer warming of the water threaten the trout from 22 to 24 °C. Its monitoring is carried out jointly by the National Park of the Semois Valley and the Semois-Chiers River Contract. Every kayaker has a part to play in it.
Paddling as a responsible observer
- Silence is your best ally: it makes all the difference when approaching wildlife.
- Keep your distance from the riverbank woodland, the shallows and any animal — you observe, you do not pursue.
- Only land at authorised launch points. The Bohan-Membre reserve and the Natura 2000 zones are not for landing: they are visited on foot, along the waymarked paths.
- Do not pick or take anything, and carry away all your waste.
- Do not disclose the location of a nest, a lodge or a feeding site.
Observing nature, paddle in hand
The wildlife and flora of the Semois reveal themselves only to those who take the time to look. A kayak descent on one of the routes from Chiny, Herbeumont, Bouillon, Vresse or Bohan is the finest way to enter this setting without disturbing it. And if you paddle all the way down to Bohan, look up towards the island of Bohan and its red Ardennes sheep, another fine nature story of the valley.
Sources: National Park of the Semois Valley (educational trail "river birds", natural heritage); Ardenne & Gaume (Bohan-Membre reserve); Biodiversity in Wallonia / DEMNA-SPW (beaver, otter, bat fact sheets); Semois-Chiers River Contract; Natagora / Aves and the 2021 Red List of the Dragonflies of Wallonia; Cultural Heritage of the Wallonia-Brussels Federation (Semois tobacco). Some species flagged "to watch" require local confirmation (observations.be, DEMNA atlas); they are presented as such, with no promise of observation.