The Semois is not regulated as a single block. The Walloon Government order of 19 March 2009 divides it into sections that have neither the same flow limits nor the same opening periods. Every rental company’s trip runs in the downstream section, the most permissive one. The framework common to all rivers is set out on the navigation conditions page.
- Official status
- Paddling allowed (since 27/10 at 11:28)
- Regulated stretch
- The Semois downstream from the bridge of Linglé
- Reference gauge
- Membre Pont
- Permitted range
- 2.2 – 50.0 m³/s
- 72-hour average
- 15.0 m³/s
Three sections, three regimes
| Section | Station | Minimum | Maximum | Open |
|---|---|---|---|---|
| Tintigny to the Vierre power plant (Chiny) | Tintigny | none | 17 m³/s | 1 October to 15 March |
| Chiny to the Chassepierre bridge | Chiny | 1.5 m³/s | 31 m³/s | all year |
| Chassepierre to the Deleau mill, then downstream | Membre | 2.2 m³/s | 50 m³/s | all year |
The upper section, between the Tintigny-Marbehan road bridge and the outflow of the Vierre power plant, is open only in winter and has a ceiling but no minimum. The other two sections have a full window, with both a minimum and a maximum.
The downstream section, where leisure trips run
From the Deleau mill, near Herbeumont, to the French border at Bohan, the Semois is a navigable waterway under Annex 1.A. The put-ins at Alle-sur-Semois, Vresse and Bouillon are all in this stretch. The reference flow is measured at the Membre station: 2.2 m³/s minimum, 50 m³/s maximum, as shown on the Semois water level page.
The minimum is judged on the average of the last 72 hours. The maximum closes the river for the day if the 8 a.m. forecast predicts the flow will be exceeded during navigation hours, or if the observed hourly flow is already above it.
Paddling hours
On the Annex 1.A stretch, the permitted hours depend on the season:
- 16 March to 15 June: 9:30 a.m. to 7 p.m.;
- 16 June to 15 October: 9:30 a.m. to 8 p.m.;
- 16 October to 15 March: 9:30 a.m. to 5 p.m.
Upstream, where the Semois falls under Annex 1.B or 1.C, the hours are shorter: 10 a.m. to 5 p.m. from 1 October to 15 June, and 9:30 a.m. to 6 p.m. from 16 June to 30 September. These sections are also closed to navigation on the opening day of trout fishing (third Saturday in March) and on the general fishing opening day (first Saturday in June). The downstream stretch is not affected by these two closures.
Getting on and off the water
You may launch and land only at designated areas, where a standard sign shows whether navigation is possible. Between two areas, you stay in the boat; only portaging along the bank to get around an obstacle is tolerated. The trips described on the Semois kayak trip page start from these areas.
Legal basis
Annex 1 lists the open sections, Annex 2 sets the flows and Annex 3 the signage. Article 4 covers periods and hours, Article 5 the put-in areas and Article 6 the daily status. The minister may also restrict navigation temporarily (Article 8), even when the flow is sufficient.