Côtes d’Armor Morbihan Draining the Guerlédan hydroelectric dam 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 Major work From 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. Guerlédan hydroelectric facility. Significant work Over the 6 months during which the lake is dry, EDF will carry out significant maintenance and modernisation work on the facilities. -R epairs to upstream dam face (lake side) -R enovation of 2 drainage valves at the dam base and their control system and conduits -B uilding 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 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 Committee A 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. Liscuis ou las g or du G Bothoa Bihan Le Longeau N164 VersLe Haut Brest du Bourg Carhaix Rostrenen Da es 4 16 4 D4 Vers Rostrenen Gouarec N Toulrodé Lan Uvelan N164 St-Gelven Canac’h Léron Toul-Bleïz N164 Ty Bris à Belle Vue D15a Les Forges des Salles Village - musée des Forges P2 Kerouillé Bois du Fao Le Guénault Le Cosquer Ty Lan Vojo Ecluse de Bellevue La Croix Rouge Kermadec St-Golven Cuilleret Bon Repos Trégnanton Trégnanton Forêt de Quénécan Passerelle de Bellevue Bois de Robot Anse de Sordan Kernévez Anse de Sordan Bois de Mérousse D15a Etang du Fourneau D15b Butte de Malvran Fo rê t Malvran Le Saut du Chevreuil Coëtudel de Moulin des Salles P10 P10 Chapelle St-Ignace Access conditions Etang Château des Salles La Fontaine au Normand Q u éand n éparking can Traffic Porh Boula Bothalec Porh Touren des Salles Chapelle Saint-Marc D15 Steep banks, unstable terrain and unsafe To facilitate driving and to ensure that La Châtaigneraie remains pose risks of slips, sinking and rock everyone remains safe, the roads around the falls. To ensure public safety, navigation lake have been altered, with red routes (for Bonalébic around and access to the bottom of the emergency services and authorised access only) lake are forbidden by prefectoral decree and blue routes. The route map is available on while it is empty. Only 5 bodies have the Morbihan and Côtes d’Armor prefectures’ Le Stang Ker Antoine received State permission to safely access websites. D15 Le Gouvello Len-Bihan the lake bed with members of the public to In addition, car parks have been createdLanniguel and Le Bretin Le Ruello Vers Lannivon * provide specific signs have been put in place. Silfiacguided tours . Lande de Perret Goëzillio Perret 0 1 Ste-Brigitte Guernauter Landroanec Lanmeur Gohfornic Kervranic Porham Penh La Lande du Gouvello Allée c de Bot e Le Garly Le Breuil du Chêne Entry Portespoints d’entrée P2 Car parks Parkings Car park accessaux routes Voies d’accès parkings Circulation à sens unique One-way traffic Accès aux points Viewpoint access de vue panoramiques P4 Porte d’entrée defloor descente Entrance to lake au fond du lac - Visites Guided visits only guidées uniquement P4 Access for peopleàwith Accès Personnes mobilité reduced réduite mobility La Guerdreux Porh Nagard kilomètre La Font de la La Le Halien La Gare P1 Bon Repos Kervégan 5 Le Zélo Abbaye de Bon Repos Le Mané D9 Les Granges Le Bahel Le Léty Chapelle N.D des Champs Parkings cars Coach parks Parkings Car parks Personnes for people à mobilité with reduced réduite mobility Road closed – et réservées Routes barrées authorised access exclusivement auxonly ayant-droits Lake Trail GR 341 Sentier du- Tour du lac - GR 341 ATTENTION ! CERTAINS TRONÇONS PLEASE NOTE! SOME SECTIONS ARE CLOSED DURING THE HUNTING SEASON. SONT FERMÉS EN PÉRIODE DE CHASSE. FOLLOW THEDÉVIATIONS. DIVERSIONS SUIVRE LES Bo Le Dreïno Porz Quélennec Bézénan Kerursule Montplaisir La Lande Blanche D767 Kerbiquet Ker Labour Kerscouarnec Guernivan Bellevue N164 Le Renderff Kerguillaume La Lande de St-Golven Botminy Kerjoly Kergoff 11 D1 Le Mané Keriven P3 Centre Equestre L Bois de Caurel e Guerl La Lande du Cerf Porh Robert Toulidoué Base départementale de plein air Sainte-Tréphine Barrage de Guerlédan Lann Guilloux Porh Antoine Kerlun Lann Vihan Toul er Roc’h La Lande Botcol Gouliadec Porh Quidu Ruisseau Lannmeur Le Bois du Brons La Lande de Trévéjean Kerouarc’h Malachap Kersec’h Trévejean Musée de l’Electricité Eglise Paroissiale P7 Le Kerbellec D156 Guergann La Lande de Bézidel Porh Lucas ot er Mohet Ker Anna Bois de Justice Keriel Kerdanio Lisquily Kerl Quénécan Tachenno Kergoric La Lande du Resto Kermarec Chapelle Jean Poulancre de Le Corboulo Vers Cléguérec houëdo Le Stivell Kerberic Le Touldren Poul Marc’h Pe Kervos Anse de Guerlédan Rond-Point du Lac D18 couver te er Mohet D35 D18 Kerihuel Centrale hydroélectrique P8 St-Aignan Brons Le Petit Paris Prat Pouchot Château Mûr de Bretagne D31 de Corboulo Porh er Lann Gaurebout Toulpérenno D6 D18 Croix Blanche Botplançon Bois de Toul er Roc’h Le Baraval Kerguichardet Blave t Pléquélen Trémer Poulhibet Ruisseau D767 Vers Lorient Vannes Pontivy Le Pontoir Bézidel * 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. Discover the drained 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. Photos de la dernière vidange du lac en 1985 Rossu D767 Corn er Lann Le Quélo Favanic Guernmouly P6 Site de Castel Finans Les Quatre Vents N164 Rond-Point du LacLa Villeneuve Suilherf Sainte-Tréphine Chapelle Goasnéjon Porh Perzo Le Quinquis Vers Kermur Rennes Loudéac La Ville Jan Saint-Brieuc Zone ar tisanale P5 an Botponal Argoat Bois Cornec éd Bois du Pouldu N164 Tréfaut Landroanec Landroanec Village de Vacances Beau Rivage Sordan an Porz Guer Les Granges ac d P9 Caurel Bizidel Le Martray Beau Rivage P4 e Le Punso Malabry Kerbranic N164 t Corn er Hoët Coat Correc D18 La Lande du Pelletier D767 Toull Du taine ande Vers Corlay Corn Coat 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. Pléguéle E Y T A O Z The Guerlédan Dam: full of history The 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 Dam Z Plant E Reservoir R Penstocks (deliver water from the reservoir to the production units) T Spillways Y Observation post R (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 U outlet valves I 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 waterrelated 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 The empty Guerlédan dam seen from upstream. DAM RESERVOIR TURBINE WATER INTAKE VALVE GENERATOR INTAKE TUNNEL TRANSFORMER HIGH VOLTAGE PYLON BOTTOM VALVE TAILRACE CANAL 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. Surveying the dam using a pendulum. A 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 Création graphique : www.studio-magellan.com - Février 2015 - Crédits photographiques : © EDF, FRANCOIS LEPAGE, NICOLAS CHARLES, STEPHANIE DELUGEAU, CONSEIL GÉNÉRAL DES CÔTES D’ARMOR, DR. A whole host of activities