Côtes d’Armor Morbihan
From March to November 2015,
Major work to ensure the long-term safety of the dam
Find the latest news about the draining at: www.guerledan2015.morbihan.gouv.fr www.guerledan2015.cotes-darmor.gouv.fr
Draining the
Guerlédanhydroelectric dam
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Major workFrom March to October 2015, EDF will undertake a complete technical examination of the Guerlédan hydroelectric dam by draining the entire reservoir. e4M is being invested in this important work which will involve around 30 EDF employees and several other companies, including companies from the local area.
This legally-required operation is strictly regulated and is necessary to guarantee the long-term safety of the dam. The project, which has been in preparation for 2 years, will allow EDF to inspect and repair the sections of the dam that are normally underwater and carry out various other work.
The drainage schedule
March - April lake is gradually emptied.
May - October lake is fully drained / work carried out.
From November natural filling of the lake.
Early 2016 hydroelectric station returns to operation.
Significant workOver the 6 months during which the lake is dry, EDF will carry out significant maintenance and modernisation work on the facilities.
- Repairs to upstream dam face (lake side)
- Renovation of 2 drainage valves at the dam base and their control system and conduits
- Building a cofferdam for the bottom outlet conduits (so that they can undergo maintenance without having to drain the reservoir in future)
- Maintenance of water intake grills
Guerlédan hydroelectric facility.
How will water quality be guaranteed?EDF will continually monitor the water quality (dissolved oxygen, levels of suspended matter, etc.) in real time before and during the drainage operation. A temporary laboratory will be set up at the foot of the dam for this purpose.
What will happen to the fish?Some of the fish will be captured alive while the lake is lowered, then released into nearby fishing sites. The rest of the fish will be collected and sold.
Following draining, when the reservoir has refilled, 13 tonnes of fish will be reintroduced and fishing should recommence at the end of 2017.
EDF water analysis laboratory.
Drainage Monitoring CommitteeA committee responsible for monitoring the work and helping with the decision making process will be in place throughout the drainage operation. Members of the committee (Government departments, fishing groups, drinking water producers etc.) receive regular information on water quality and fish management from EDF.
Etang des Salles
Etang du
Fourneau
à
Ruisseau de Corboulo
Blavet
Le
Ruisseau
de
Poulancre
Gorges
du
Daou
las
Lac de Guerlédan
Lande de Perret
Bois de Mérousse
Bois
du Fao
Bois de Toul er Roc’h
Bois de
Justice
Bois de
Caurel
Bois
de Robot
Bois Cornec
Bois du
Pouldu
Forêt de
Quénécan
Le Bois du Brons
F o r ê t
d e
Q u é n é c a n
N164
N164
N164
N164
D76
7
D767
D18
D18
D31
D156
D15
D15a
D15b
D15a
D44
D95
D111
N164
D18 D35
D63
Le Breuil du Chêne
Allée couver tede Bot er Mohet
Chapelle Jean
Eglise Paroissiale
La Fontainede la Lande
La Gare
Ecluse de Belle
Passerellede Bellevue
vue
Abbaye de Bon Repos
Les Forges des SallesVillage - musée des Forges
Le Saut du Chevreuil
Moulin des Salles
Château des SallesLa Fontaine au Normand
Chapelle St-Ignace
Chapelle Saint-Marc
Butte deMalvran
Barrage de
Basedépartementale
de plein air
Centrale hydroélectrique
Guerlédan
Zone ar tisanale
CentreEquestre
Village deVacances
Chapelle N.D des Champs
Le Bahel
Le Léty
Kernévez
Le Guénault
Len-Bihan
Guerdreux
Kervranic
Goëzillio
Le Ruello
Le Garly
Le BretinLannivon
Bot er Mohet
Guergann
Ker Anna Trémer
Kerbellec
Le Pontoir
Kergoric
Kerberic
Lisquily
Squiviec
Pléquélen
Le Touldren
Kerdanio
TrévejeanKersec’h
Kerouarc’h
Kerbastard
Kermarec
KervosKerihuel
La Villeneuve
Kerguichardet
Le Stivell
Pescren
ChâteaubriandToulpérenno
Le Quélo
Gaurebout
Rossuliet
Tréfaut
Le Martray
Kermur
Bizidel
Kerguillaume
Malabry
Coat CorrecCorn er Hoët
Corn Coat
Montplaisir
Le Dreïno
Kerscouarnec
Kerbranic
Kerbiquet
Kerursule
Toull Du
Botminy
Porz Guer
GuernivanLe Halien
Kerbiquet
Le Cosquer
Ty Bris
Le Renderff
Le ManéKerouillé
Cuilleret
Les Granges
Le Zélo
Belle Vue
Liscuis
Toul-BleïzToulrodé
Le Longeau
Le Hautdu Bourg
Le Véry
Lan Uvelan
La Châtaigneraie
GohfornicPorh Nagard
Ker Antoine
Bonalébic
Bézidel
Penhouëdo
Prat Pouchot Le Petit Paris
Porh LucasPoulhibet
Pléguélen
KerlezLe Néveit
Gouliadec
Le Baraval
Kerlun
Corn er LannLes Quatre Vents
Porh Antoine
LanmeurBrons
Lanniguel
Suilherf
Lann Guilloux
Botplançon
Bothalec Le Quinquis
Porh Boulan
Botponal
GoasnéjonPorh Perzo
Sordan
Porh Touren
Canac’h Léron
Bothoa Bihan
Le Mané
Ty Lan Vojo
La Lande du Pelletier
La Lande de St-Golven Kerjoly
La Lande Blanche
Porz Quélennec
Ker LabourLe Punso
Bellevue
La Ville Jan
Guernmouly Favanic
MalachapLa Lande de Trévéjean
Tachenno
Quénécan
La Lande du Resto
Poul Marc’hLa Croix Blanche
La Lande de BézidelLa Lande du Gouvello
Porham
Le Stang
La Lande du Cerf
ToulidouéPorh Robert
Argoat
St-Golven
Les Granges
Lann Vihan
Toul er Roc’hLa Lande
Porh er Lann
Porh Quidu
Keriven
Guernauter
Lannmeur
Le Corboulo
Le Gouvello
Keriel
Botcol
Malvran
Coëtudel
La Croix Rouge
Kermadec
Bézénan
Kergoff
Kervégan
Bon Repos
Trégnanton
Beau Rivage
Landroanec
Rond-Point du Lac
Anse deSordan
St-Gelven
Ste-Brigitte
St-Aignan
Site de Castel Finans
Sainte-Tréphine
Mûr de Bretagne
Caurel
Musée del’Electricité
Trégnanton
Anse de Sordan
Beau Rivage
Anse de Guerlédan
Rond-Point du Lac
Chapelle Sainte-Tréphine
Landroanec
Bon Repos
P1
P2
P3
P4P5
P6
P7
P8
P9
0 1
kilomètre
P10
P10
VersBrestCarhaixRostrenen
N164
VersRostrenenGouarec
N164
VersSilfiacPerret
D15
N164
Vers Corlay
Vers RennesLoudéacSaint-Brieuc
VersLorientVannesPontivy
Vers Cléguérec
D767
D767D18
Voies d’accès aux parkings
Circulation à sens unique
Routes barrées et réservées exclusivement aux ayant-droits
Portes d’entréeLandroanec
Accès aux points de vue panoramiques
Porte d’entrée de descente au fond du lac - Visites guidées uniquement
Accès Personnes à mobilité réduite
Photos de la dernière vidange du lac en 1985
P4 Parkings cars
P4Parkings Personnes à mobilité réduite
P2 Parkings
Sentier du Tour du lac - GR 341 ATTENTION ! CERTAINS TRONÇONS SONT FERMÉS EN PÉRIODE DE CHASSE. SUIVRE LES DÉVIATIONS.
Vous êtes sur un site naturel.Ayez le geste éco-citoyen !
Utilisez les points de collecte des déchets mis à disposition sur les parkings et aux portes d’accès au lac.
Access conditionsSteep banks, unstable terrain and unsafe remains pose risks of slips, sinking and rock falls. To ensure public safety, navigation around and access to the bottom of the lake are forbidden by prefectoral decree while it is empty. Only 5 bodies have received State permission to safely access the lake bed with members of the public to provide guided tours*.
Traffic and parking To facilitate driving and to ensure that everyone remains safe, the roads around the lake have been altered, with red routes (for emergency services and authorised access only) and blue routes. The route map is available on the Morbihan and Côtes d’Armor prefectures’ websites. In addition, car parks have been created and specific signs have been put in place.
Entry points
Viewpoint access
Entrance to lake floor - Guided visits only
Access for people with reduced mobility
Car parks
Coach parks
Car parks for people with reduced mobility
Car park access routes
One-way traffic
Road closed – authorised access only
Lake Trail - GR 341 PLEASE NOTE! SOME SECTIONS ARE CLOSED DURING THE HUNTING SEASON. FOLLOW THE DIVERSIONS
Etang des Salles
Etang du
Fourneau
à
Ruisseau de Corboulo
Blavet
Le
Ruisseau
de
Poulancre
Gorges
du
Daou
las
Lac de Guerlédan
Lande de Perret
Bois de Mérousse
Bois
du Fao
Bois de Toul er Roc’h
Bois de
Justice
Bois de
Caurel
Bois
de Robot
Bois Cornec
Bois du
Pouldu
Forêt de
Quénécan
Le Bois du Brons
F o r ê t
d e
Q u é n é c a n
N164
N164
N164
N164
D76
7
D767
D18
D18
D31
D156
D15
D15a
D15b
D15a
D44
D95
D111
N164
D18 D35
D63
Le Breuil du Chêne
Allée couver tede Bot er Mohet
Chapelle Jean
Eglise Paroissiale
La Fontainede la Lande
La Gare
Ecluse de Belle
Passerellede Bellevue
vue
Abbaye de Bon Repos
Les Forges des SallesVillage - musée des Forges
Le Saut du Chevreuil
Moulin des Salles
Château des SallesLa Fontaine au Normand
Chapelle St-Ignace
Chapelle Saint-Marc
Butte deMalvran
Barrage de
Basedépartementale
de plein air
Centrale hydroélectrique
Guerlédan
Zone ar tisanale
CentreEquestre
Village deVacances
Chapelle N.D des Champs
Le Bahel
Le Léty
Kernévez
Le Guénault
Len-Bihan
Guerdreux
Kervranic
Goëzillio
Le Ruello
Le Garly
Le BretinLannivon
Bot er Mohet
Guergann
Ker Anna Trémer
Kerbellec
Le Pontoir
Kergoric
Kerberic
Lisquily
Squiviec
Pléquélen
Le Touldren
Kerdanio
TrévejeanKersec’h
Kerouarc’h
Kerbastard
Kermarec
KervosKerihuel
La Villeneuve
Kerguichardet
Le Stivell
Pescren
ChâteaubriandToulpérenno
Le Quélo
Gaurebout
Rossuliet
Tréfaut
Le Martray
Kermur
Bizidel
Kerguillaume
Malabry
Coat CorrecCorn er Hoët
Corn Coat
Montplaisir
Le Dreïno
Kerscouarnec
Kerbranic
Kerbiquet
Kerursule
Toull Du
Botminy
Porz Guer
GuernivanLe Halien
Kerbiquet
Le Cosquer
Ty Bris
Le Renderff
Le ManéKerouillé
Cuilleret
Les Granges
Le Zélo
Belle Vue
Liscuis
Toul-BleïzToulrodé
Le Longeau
Le Hautdu Bourg
Le Véry
Lan Uvelan
La Châtaigneraie
GohfornicPorh Nagard
Ker Antoine
Bonalébic
Bézidel
Penhouëdo
Prat Pouchot Le Petit Paris
Porh LucasPoulhibet
Pléguélen
KerlezLe Néveit
Gouliadec
Le Baraval
Kerlun
Corn er LannLes Quatre Vents
Porh Antoine
LanmeurBrons
Lanniguel
Suilherf
Lann Guilloux
Botplançon
Bothalec Le Quinquis
Porh Boulan
Botponal
GoasnéjonPorh Perzo
Sordan
Porh Touren
Canac’h Léron
Bothoa Bihan
Le Mané
Ty Lan Vojo
La Lande du Pelletier
La Lande de St-Golven Kerjoly
La Lande Blanche
Porz Quélennec
Ker LabourLe Punso
Bellevue
La Ville Jan
Guernmouly Favanic
MalachapLa Lande de Trévéjean
Tachenno
Quénécan
La Lande du Resto
Poul Marc’hLa Croix Blanche
La Lande de BézidelLa Lande du Gouvello
Porham
Le Stang
La Lande du Cerf
ToulidouéPorh Robert
Argoat
St-Golven
Les Granges
Lann Vihan
Toul er Roc’hLa Lande
Porh er Lann
Porh Quidu
Keriven
Guernauter
Lannmeur
Le Corboulo
Le Gouvello
Keriel
Botcol
Malvran
Coëtudel
La Croix Rouge
Kermadec
Bézénan
Kergoff
Kervégan
Bon Repos
Trégnanton
Beau Rivage
Landroanec
Rond-Point du Lac
Anse deSordan
St-Gelven
Ste-Brigitte
St-Aignan
Site de Castel Finans
Sainte-Tréphine
Mûr de Bretagne
Caurel
Musée del’Electricité
Trégnanton
Anse de Sordan
Beau Rivage
Anse de Guerlédan
Rond-Point du Lac
Chapelle Sainte-Tréphine
Landroanec
Bon Repos
P1
P2
P3
P4P5
P6
P7
P8
P9
0 1
kilomètre
P10
P10
VersBrestCarhaixRostrenen
N164
VersRostrenenGouarec
N164
VersSilfiacPerret
D15
N164
Vers Corlay
Vers RennesLoudéacSaint-Brieuc
VersLorientVannesPontivy
Vers Cléguérec
D767
D767D18
Voies d’accès aux parkings
Circulation à sens unique
Routes barrées et réservées exclusivement aux ayant-droits
Portes d’entréeLandroanec
Accès aux points de vue panoramiques
Porte d’entrée de descente au fond du lac - Visites guidées uniquement
Accès Personnes à mobilité réduite
Photos de la dernière vidange du lac en 1985
P4 Parkings cars
P4Parkings Personnes à mobilité réduite
P2 Parkings
Sentier du Tour du lac - GR 341 ATTENTION ! CERTAINS TRONÇONS SONT FERMÉS EN PÉRIODE DE CHASSE. SUIVRE LES DÉVIATIONS.
Vous êtes sur un site naturel.Ayez le geste éco-citoyen !
Utilisez les points de collecte des déchets mis à disposition sur les parkings et aux portes d’accès au lac.
Discover the drained lake
* Only the tourist offices of Pontivy communauté, Pays Centre Bretagne and Kreiz Breizh, as well as the Guerlédan departmental base and the Mûr-de-Bretagne holiday centre can organise visits to the lake.
Map created by the Département of Côtes d’Armor (draft version). The final map version will be available in tourist offices from the 1st of February.
full of historyThe incredible story of the dam’s construction began in 1923. It took seven years of work and thousands of workers before the dam was commissioned in 1930. The project was begun by the Société générale d’entreprises (General Business Company), then was soon transferred to the Union hydroélectrique Armoricaine (Côtes d’Armor Hydroelectric Union). EDF took over the running of the dam in 1946 when gas and electricity were nationalised.
A
O
Z
T
Y E
The Guerlédan Dam:
Specifications The Guerlédan hydroelectric facility comprises a dam and a hydroelectric power plant. The artificial lake created by the dam has 3 functions: producing electricity, contributing to the supply of drinking water, and allowing water-related activities to take place.
- Dam type: gravity
- Height: 45 m
- Width: 206 m
- Thickness: 33.5 m at the base
- Production units: 4 (3 original units and an additional unit built in 1933)
- Power generated by the plant: 15 MW, or the equivalent of the annual energy required by a town of 15,000 people
- Reservoir: 51 million m3 of water
- Spillways: 2 valves which can extract up to 465 m3/s
R
U
I
A Dam
Z Plant
E Reservoir
R Penstocks (deliver water from the reservoir to the production units)
T Spillways
Y Observation post (allows the facility to be monitored 24/7, particularly in the event of extreme climatic events)
U Administrative buildings
I Transformation stations
O Bottom drainage outlet valves
The empty Guerlédan dam seen from upstream.
From water to electricity, how does it work?The dam makes it possible to accumulate a large quantity of water, forming a lake 1. When the valves are opened, the water runs into pipes 2 which channel it towards production units located in the power plant. The water drives the rotation of the turbine 3. The turbine drives the generator 4 which produces an electrical current whose voltage is increased by a transformer 5. The current is then carried by high voltage lines (63,000 volts). When it leaves the plant, the water returns to the River Blavet.
How is the dam monitored?EDF operators monitor, check and examine the dam regularly. They take measurements using various tools (piezometers, drains, etc.), and perform visual examinations and periodic testing. This monitoring is supplemented by in-depth technical inspections annually and inspections of the underwater sections every 10 years (for dams over 20 m high only). The underwater inspections are carried out using a remotely operated vehicle where possible but sometimes require the entire lake to be emptied.
RESERVOIR
DAM
WATER INTAKE VALVE
BOTTOM VALVE
INTAKE TUNNEL
TURBINE
GENERATOR
TRANSFORMER
TAILRACE CANAL
HIGH VOLTAGE
PYLON
Surveying the dam using a pendulum.
A whole host of activitiesA variety of events have been organised throughout the summer to allow you to discover this transient landscape and this important hydroelectric work. Events include sound and light shows, performing arts, open-air projections, exhibitions, and more!
Discover the full programme of activities in tourist offices and at www.lacdeguerledan.com C
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