Arguenon
 Mouth of the Arguenon between the communes of Créhen and Saint-Cast-le-Guildo | |
 Course of the Arguenon | |
   | |
| Location | |
|---|---|
| Country | France |
| Region | Brittany |
| Department | Côtes-d'Armor |
| Physical characteristics | |
| Source | |
| • location | Le Gouray |
| • coordinates | 48°19′11″N 2°31′17″W / 48.3196°N 2.5214°W |
| • elevation | 200 metres (660 ft) |
| Mouth | English Channel |
• location | near Saint-Jacut-de-la-Mer |
• coordinates | 48°34′13″N 2°13′05″W / 48.5702°N 2.218°W |
• elevation | 0 metres (0 ft) |
| Length | 53.36 kilometres (33.16 mi) |
| Basin size | 534 square kilometres (206 sq mi) |
| Discharge | |
| • average | 4.83 cubic metres per second (171 cu ft/s) |
| Basin features | |
| Tributaries | |
| • left | Guébriand |
| • right | Rosette |
The Arguenon (French pronunciation: [aʁɡənɔ̃]; Breton: Argenon) is a French coastal river in the Côtes-d'Armor department of the Brittany region. It flows into the English Channel.
Geography[edit]
The length of the watercourse is 53.4 kilometres (33.2 mi).[1][2][a] The river rises in the commune of Le Gouray in Côtes-d'Armor and flows into the sea near Saint-Jacut-de-la-Mer, in the commune of Créhen, in the Bay of Arguenon.[3] The Arguenon is very wide between Jugon-les-Lacs and Plorec-sur-Arguenon. The Ville-Hatte dam built in 1972 to supply the department with drinking water has created a water reservoir more than 10 kilometres (6.2 mi) long named Lac d'Arguenon.
The Arguenon runs northeast from its source to Jugon-les-Lacs, north between Jugon-les-Lacs and Plorec-sur-Arguenon, northeast again between Plorec-sur-Arguenon and Plancoët and north-northeast from Plancoët to its mouth.
During high tides a small tidal bore rises up the river, up to the height of the Guildo bridge.
Communes and cantons crossed[edit]
The Arguenon's course is entirely within the Côtes-d'Armor department. It crosses twelve communes, from upstream to downstream: Le Gouray (source), Plénée-Jugon, Dolo, Jugon-les-Lacs, Plorec-sur-Arguenon, Plédéliac, Pléven, Bourseul, Pluduno, Plancoët, Saint-Lormel, Créhen and Saint-Cast-le-Guildo (mouth).[1]
Managing body[edit]
The managing body is SAGE Arguenon – Baie de la Fresnaye.[4]
Tributaries[edit]
The Arguenon has four named tributary streams, one river and 10 unnamed tributaries including:[1]
- Rosette river, 31.2 kilometres (19.4 mi), enlarged by the Rieule, 13.8 kilometres (8.6 mi).
- Bos Robert stream, 5.6 kilometres (3.5 mi), in the two municipalities of Langourla and Plénée-Jugon.
- Quiloury stream, 14.7 kilometres (9.1 mi), in the four municipalities of Le Gouray, Penguily, Plénée-Jugon and Saint-Glen.
- Étang du Guillier stream, 6.2 kilometres (3.9 mi), over the four municipalities of Jugon-les-Lacs, Plédéliac, Plestan and Tramain.
- Montafilan stream, 16.3 kilometres (10.1 mi), in the six municipalities of Corseul, Créhen, Plancoët, Plélan-le-Petit, Saint-Maudez and Saint-Michel-de-Plélan.
We can also add, according to the National Institute of Geographic and Forest Information or Géoportail, and since the Guébriand is not a river in its own right:
- The Guébriand, 19.8 kilometres (12.3 mi), passing through the commune of Landébia and joining the Arguenon between the communes of Saint-Lormel and Saint-Cast-le-Guildo at the entrance to Arguenon bay opposite the town of Créhen.
Hydrology[edit]
Arguenon at Jugon-les-Lacs[edit]
The Arguenon has been observed in Jugon-les-Lacs since 1972 at station J1103010 L'Arguenon, at an altitude of 31 metres (102 ft) with a catchment area of 104 kilometres (64.62 mi).[5] The annual average of its flow at this point is 0.829 cubic metres per second (29.3 cu ft/s).[5]
| Average flow at Jugon-les-Lacs in m3/s |
 |
| Hydrological station: J1103010 - L'Arguenon in Jugon-les-Lacs 2015-08-08 - data calculated over 44 years from 1972 to 2015 |
Low water[edit]
At low water the minimum flow rate of the watercourse recorded for three consecutive days in a month, during a five-year dry period, was 0.014 cubic metres per second (0.49 cu ft/s).[5]
Floods[edit]
During the observation period, the maximum daily flow was observed on 28 February 2010 at 24.80 cubic metres per second (876 cu ft/s). The maximum instantaneous flow (QIX: quantité instantanée maximale) was observed at 14:21 on 28 February 2010 was 36.10 cubic metres per second (1,275 cu ft/s), and at the same time the instantaneous maximum height was 217 centimetres (85 in).[5]
The 10-year QIX is 23 cubic metres per second (810 cu ft/s), the 20-year QIX is 28 cubic metres per second (990 cu ft/s) and the 50-year QIX is 34 cubic metres per second (1,200 cu ft/s) while the 2-year QIX is 11 cubic metres per second (390 cu ft/s) and the 5-year QIX is 18 cubic metres per second (640 cu ft/s).[5]
The Arguenon has experienced several significant floods. The first took place in 1974. The water overflowed 1 metre (3 ft 3 in) on the Plancoët quay, causing major and widespread damage. The second took place in 2010, this time with 50 centimetres (20 in) on the quayside. The floodwater affected a lot of businesses. The last took place in February 2014, with 1.45 metres (4 ft 9 in) on the quays. Shops were closed permanently and a park was completely flooded.
Depth of runoff and specific flow[edit]
The depth of runoff in this part of the river's catchment area is 253 millimetres (10.0 in) annually, which is a little lower than the average in France. The specific flow rate reaches 8.0 litres per second (106 imp gal/min) per 1 square kilometre (0.39 sq mi) of basin.[5]
Facilities and ecology[edit]
The Arguenon is crossed by Route nationale 176 and Route nationale 12.
The Arguenon estuary is protected by a 381 hectares (940 acres) Zone naturelle d'intérêt écologique, faunistique et floristique.[6]
Arguenon Bay is part of the Natura 2000 zone Lancieux Bay, Arguenon Bay, Saint Malo and Dinard Archipelago.[7]
Notes[edit]
Citations[edit]
Sources[edit]
- Fiche cours d'eau - L'Arguenon (J11-0300), Sandre; Service d'administration nationale des données et référentiels sur l'eau, retrieved 2021-09-15
- Géoportail (France), Géoportail, Institut national de l'information géographique et forestière, retrieved 15 August 2015
- "INPN - FSD Natura 2000 - FR5300012 - Baie de Lancieux, Baie de l'Arguenon, Archipel de Saint Malo et Dinard - Description", inpn.mnhn.fr, retrieved 2020-11-11
- "INPN, ZNIEFF 530030026 - ESTUAIRE DE L'ARGUENON - Description" (PDF), inpn.mnhn.fr, retrieved 2020-11-11
- "L'Arguenon à Jugon-les-Lacs", Banque Hydro (in French), Ministry of the Ecological Transition (France), retrieved 2021-09-15
- Observatoire des Poissons Migrateurs en Bretagne, L'Arguenon, le Montafilan et le Guébriand, retrieved 15 September 2021
- "SAGE Arguenon - Baie de la Fresnaye", www.smap22.fr, retrieved 2020-11-11