LIFE-nature project: Roer migration Restoring migration possibilities for 8 Annex II species in the river Roer

Transcription

1 RESTORATION OF FISH MIGRATION IN THE RIVER ROER 2008 February LIFE-nature project: Roer migration Restoring migration possibilities for 8 Annex II species in the river Roer A rural stretch of the river Roer near Melick. A largely free-meandering river that winds its way mainly through open countryside. There are many species of fish in the Roer. Infact, it is one of the most species-rich rivers in the Netherlands for fish. Waterschap Roer and Overmaas Regional Water Authority restores fish migration in the river Roer The river Roer forms a potential habitat for species of fish that migrate between the river Maas (Meuse) and the Roer. The Dutch section of the Roer also forms a route for fish that migrate between the North Sea and the Maas to their spawning grounds in the upper (German) section of the Roer. Since last year, the Maas has been fully accessible to migratory fish from the North Sea to the Roer. Waterschap Roer and Overmaas Regional Water Authority has removed the last obstacles to fish migration in the Roer by building two new fish ladders in the river - one in the Hambeek and one in Roermond. This opens the Roer to migratory fish all the way to Germany. This report, which is aimed at interested non-professionals, briefly summarises the how and why of fish migration in the Roer system and explains its importance. Further information and more photographs can be found at Table of contents What is fish migration? Fish ladders in the Hambeek and at the ECI Hydropower Installation Monitoring the recovery of the Roer s natural fish stock Underwater viewing of fish in the Roer Roer meander about to break through Communication

2 What is fish migration? Fish migration is neither more nor less than the movement of fish between their normal habitat and their breeding ground (spawning ground). A distinction is made between short migration - movement between a river and its tributaries - and long-range migration, which is movement from the sea via large rivers to tributaries and streams. Why is undisrupted fish migration necessary? Fish need to be able to reach the spawning grounds in order to reproduce. If they cannot do so, the species may become extinct and, in the past, that has indeed occurred. By removing obstacles - in this case only those in the river Roer - the water board also hopes to bring new populations - particularly of salmon and sea trout - back into the Roer river system. Atlantic salmon Fish migration in the Roer system The Roer forms a potential habitat for fish species that migrate between the river Maas (Meuse) and its tributary the Roer. These include barbel, beaked carp and bullhead (miller s thumb). The Dutch section of the Roer forms a through route for fish that migrate between the North Sea and Maas to their spawning grounds in the upper Roer, which is in Germany. These species are Atlantic salmon, sea trout, sea lamprey and the European river lamprey. This year, this route became free from obstacles. Migrating fish / spawning ground The Roer fish migration project Access to the Roer river ladder in the Hambeek branch of the river and the ECI hydropower installation in the Roer itself. The aim of the Roer fish migration project was to restore migration in the river Roer by removing these obstacles. To achieve this, a vertical slot fish ladder was built at the hydropower installation and a new fish pass (a Raugerinne- Beckenpass) made in the Hambeek so that all fish species can migrate. Why restore fish migration in the Roer? Very recently, after a 125-year absence, a few salmon have been spotted in the Roer, below the ECI hydropower installation in Roermond. Other protected species also occur in the Roer, including the brook lamprey, European river lamprey, Eurasian minnow and bullhead. The Roer is one of the most species-rich rives in the Netherlands. This is why the Dutch government is busily providing all dams and weirs in the river Maas with fish ladders, so that tributaries such as the Roer can once again be accessible to fish migrating from the North Sea to their spawning grounds in Germany. The aim is to create a single 2

3 Eurasian minnow The fish ladder at the reservoir in Obermaubach (Eifel, Germany) recently brought came operation. Bullhead accessible river system from the North Sea to the streams and brooks of the upper Roer in Germany. Moreover, water management partners on either side of the border are aiming to restore species that have died out in the Roer, such as salmon ands sea trout. Expected results Waterschap Roer and Overmaas Regional Water Authority expects positive results from the newly constructed fish ladders. These facilities will benefit the following fish species: Bullhead, river lamprey, brook lamprey, sea lamprey, dojo loach (weatherfish), bitterling, European catfish, loach and salmon. The Germans are also making efforts to encourage these species to thrive again in the Roer. For example, the fish ladder at the reservoir in Obermaubach, in the German Eiffel region, is now in use. This fish ladder bypasses a rise of 7 metres. This only makes the construction and modification of facilities in the Netherlands to make fish migration possible (in the Roer and Hambeek) even more important. Moreover, by restoring Habitat Directive species such as the river lamprey, the water board reinforces the status of the Roer valley as a Natura 2000 area. The urban Roer The rural Roer Building work to remove the obstacle to fish migration at the ECI hydropower installation. European catfish 3

4 Fish ladders in the Hambeek and at the ECI Hydropower Installation The obsolete fish ladder in the Hambeek. Fishing the Hambeek Hambeek The Hambeek branches off the Roer shortly before it joins the river Maas. Until recently, it was little used by migrating fish, but that is now changing. The fish ladder in the Hambeek in Roermond was built in the 1980s. It became evident that the height difference of the separate steps in the fish ladder was too great for some migratory species, so the water board then modified the steps of the ladder. The fish pass is now made from large erect rocks fixed into riprap (shot rock) and concrete. The Regional Water authority has made these modifications so that even the smaller species can migrate through the fish pass. Fish entrance Another modification has been to move the fish entrance to the Balgstuw, which is an inflatable dam. This plays a major role in ensuring that fish migrating upstream can find the entrance of the fish ladder even during periods of high flow in the Roer when there is a lot of water flowing over the dam. When fish migrate, they always follow the main stream, that is, the branch of the river with the strongest current. Consequently, migrating fish swim up the Hambeek towards the Balgstuw dam, which they are not able to swim over. By putting the entrance to the fish ladder directly next to it, however, they can migrate upstream without interruption by following the current. Fish pass Hambeek Bron: Ingenieursburo Floecksmühle uit Aken. The Roer and Overmaas Regional Water Authority began in 2006 with improvements to the fish ladder in the Hambeek in Roermond. This made the fish ladder passable for all migrating fish. Aerial photo the Roermond fish ladder under construction Bron: Ingenieursburo Floecksmühle uit Aken. The new fish ladder under construction. The rocks are placed very precisely according to calculations that ensure the correct pattern of flow. 4

5 Fish pass in the Hambeek under Construction Fish pass in the Hambeek Fish entrance The arrows show the desired swim direction. The fish enter the ladder at the dam and migrate upstream via the fish pass (shown on the map as a green spillway ). 2.5 meter height difference The fish ladder is 470 meters long. It needs to allow fish to climb 2.5 metres. The water Regional Water Authority has use natural materials such as gravel and large stones. This creates structures and flow patters that allow the fish to swim up and down. A drawing showing this in cross- and longitudinal sections can be found elsewhere in this report. The water board can sample the fish pass using gage traps, and so keep a check on how well the ladder is working. This also shows how many of species are passing through the ladder. Fish ladder at the ECI Roer Hydropower Installation The fish ladder at the hydropower installation in Roermond has the layout of a labyrinth. The path the fish has to take to rise 2.4 m and by-pass the installation goes via a series of switchbacks. With the modification of the fish ladder in the Hambeek and the construction of the new ladder around the hydro installation the last obstacles to fish migration in the Roer have been removed. Salmon spawning grounds If the water board has done nothing, all the other initiatives, such as creating salmon egg nurseries in the Eiffel, the removal of The fish ladder under construction at the hydro installation a major operation. 5

6 The fish ladder under construction obstacles to fish migration in Germany, improving water quality and allowing the Roer to meander so as to create spawning grounds, would have been pointless. Building these facilities has opened the Dutch section of the Roer, including its tributaries, to threatened and protected fish species including salmon, river lamprey and sea lamprey. The fish ladder will also be passable for the Atlantic sturgeon. Although this species is no longer found in North-West Europe, the Roer will be open to it should it ever return naturally or be artificially re-established. Protective grill above the hydropower installation Fish swim downstream as well as upstream. If downstream migrating fish swim towards the hydro installation they could be killed or injured in the turbine. To prevent this, the water board has installed a "fish guide". This system includes a grille with slats at a distance of 10 mm. This prevents downstream swimming fish from ending up in the turbine. The fish ladder under construction The Roer The new (vertical slot) fish ladder at the hydro installation. A fish-protection grille The Roer forms part of the drainage basin of the river Maas (Meuse). It rises in the Hoge Venen (High Fens) of Belgium and flows via the Eiffel region of Germany towards the Netherlands, where it flows into the Maas at Roermond. The Roer is still a largely free-meandering river that winds its way through mainly open countryside. From and ecological point of view the Roer is the most valuable tributary of the Maas in the Netherlands. The Roer meanders, has high banks, has deep and shallow parts, a varied flow pattern and excellent gravel. Over recent decades, the water quality has improved considerably and various fish and plant species have increased in number or returned to the river. The returning species include the green clubtail dragonfly and the Eurasian minnow. The Roer is certainly one of the richest Dutch rivers for fish species and, with at least 41 species, is possibly the richest of all. Club tail dragon fly Placing the bridge deck 6

7 Monitoring the recovery of the Roer s natural fish stock Before the fish passes were built in the Hambeek and at the ECI hydropower installation, only a small number of fish were able to get through the poorly functioning fish ladder in the Hambeek to reach the Roer proper, and the route via the hydro installation was cut off entirely. Now that the Maas-Roer migration routes via the Hambeek and ECI instillation are open, it is interesting as well as useful to monitor the fish populations in the Roer. To do this Waterschap Roer and Overmaas Regional Water Authority will carry out a regular inventory of the fish stock. The fish stock in the Roer can only be improved by virtue of optimally functioning fish passes. This is why it is also necessary to establish how well the passes and constructions are working. Periodic fish stock survey The last fish stock survey was performed in 2003, and this will be used as a baseline. In accordance with the system used under the European Framework Directive on Water, the Roer will be sampled every six years, so in 2009 it will be sampled again. Study of the operation of the fish ladders To see whether the fish ladders are working well, the flow speeds and the way the current divides will be monitored at different places. In this way, the rocks in the fish ladder in the Hambeek can be moved to cerate optimal flow speeds and flow patterns. With the fish ladder at the ECI hydro installation, the gaps can be made wider or narrower in each compartment to adjust the flow speed and pattern. Volunteers In addition to this, the water board look at the effectiveness of the fish ladders on the basis of the numbers and species of fish passing the ladder in either direction. This is done with cage traps to catch the passing fish. The best times to measure this is during the spring (March, April and May) and in the autumn (October, November and December). Volunteers from the Roer Valley Fish Stock Management Committee (Visstand beheerscommissie or VBC) help the water board with the research. The fish caught in the cages are put into tanks, where they are counted, measured and the species determined. For fish stock studies or for fishing the rivers and streams, the water board makes grateful use of volunteers. These are volunteers from the Roer Valley Fish Stock Management Committee (VBC). 7

8 Nieuwsbrief Life-nature project Fish stock study using electrical fishing apparatus in the Hambeek and Roer Early in January 2008, the Hambeek and the renovated fish passage between the Roer and the Hambeek were electrically fished. Hundreds of fish of 27 different species were caught in the fish passage. The top catches were a 55 cm salmon (see photos) and two adult river lampreys in the morning. If nothing else, this is proof that the fish are finding the fish passage while it is still in only limited use and while the dam built on the upper side is only letting through leakage and seepage water. 8

9 Underwater viewing of fish in the Roer At the new fish ladder at the ECI hydropower installation there will be a visitors centre with an underwater viewing window. This will allow visitors to see the operation of the fish ladder from underwater and to take a look at the world of the fish in the Roer. This is one of the great desires of Waterschap Roer and Overmaas regarding education and public information. The experience of water and wildlife in the water makes the work and tasks of the water board more visible and comprehensible. The visitors room is also an attraction for people visiting the city of Roermond. The viewing window and other facilities such as a monitoring system will soon also be used for (scientific) research. Various organisations have made financial contributions towards the building of the visitors' centre. There is a lot to see in the Roer. With over forty species of fish, the Roer is one of the most species-rich rivers in the Netherlands. These species include eels, salmon, sea trout, barbel, chub, dace, river lamprey, brook lamprey and sea lamprey. For tourists, schoolchildren, local people and experts alike, a look into the Roer can be a fascinating and educational experience. There s a lot to see underwater, such as barbel. There s a lot to see, such as sea trout. The viewing window under construction 9

10 The broad perspective The whole Maas river system, consisting of the North Sea, the Maas itself and its tributaries, has for many decades had problems that have stood in the way of the maintenance and recovery of the aquatic ecosystem. Examples of this include the closing-off of the North Sea from the big Construction board rivers, the various hydropower installations in the Maas and the poor water quality in the river and its tributaries. Over the years, much has changed for the better in the Maas system. Fish can now migrate from sea to river and vice versa, the hydropower installations in the Maas have fish ladders and the water quality has greatly improved - especially in the tributaries such as the Roer. Because the Roer is once more free to actively meander, sand and gravel banks have developed. All the measures undertaken by water management organisations, including Roer and Overmaas Regional Water Authority, have led to the happy situation in which the Roer is well suited for many plant and animal species that had disappeared and which are now making a Salmon gradual comeback. These returning species include moving water-loving dragonflies such as the yellow-legged dragonfly and the green clubtail and the moving water fish, the Eurasian minnow. What s more, the tide has also turned to the benefit of salmon and sea trout. Once-in-a-lifetime natural meander breakthrough Roer meander about to break through On 8 February 2008, the river Roer in the Limburg parish of Vlodrop was about to cut off a meander. Where the river made a wide bend around a wooded island, the river is stopped from cutting off the bend by a strip of ground only 10 cm wide. What we see is a natural river process of calving banks and silting up, in the words of Jacq in den Kleef, deputy manager of the Roer and Overmaas Regional Water Authority. Outer bends calve away and inner bends silt-up. Depending on the speed of the current, obstacles in the water and the type of ground, the river carves out the easiest route through the landscape. What we see here is once-in-a-lifetime event! The Roer district was only added to the water board s area of responsibility in In the early 1990s, the water board bought the strips of land along the banks of the Roer and removed the riverbank protection that the previous owners had laid. Since then the water board's policy has been that in rural areas the river should be free to find its own way. Farmer Chrit Wolfhagen, who lives just behind the Roer meander, is also a member of Waterschap Roer and Overmaas Regional Water Authority. He tipped off the water board that something unique was about to happen. Wolfhagen: Now it will go quickly. Yesterday you could still walk over this; now there s only a pile of sand, and if that breaks through the Roer will cut off 150 metres of its course down to the Maas at Roermond. 10

11 Project costs and subsidy The project was an initiative of Waterschap Roer and Overmaas Regional Water Authority. This project was partly made possible by a more than 1.2 million Euro subsidy from the European Life-nature subsidy fund, in addition to 1.5 million Euros from other subsidies. The cost of modifying the fish ladder in the Hambeek and the construction of the fish ladder at the ECI hydropower installation in the Roer at Roermond totalled 4.5 million Euros. Life Life contributes to the implementation, development and improvement of environmental policy and legislation as well as the integration of environmental matters in other European Union policies. It also supports the development of new solutions to environmental problems that the EU examines. In addition, LIFE takes care of the implementation of policy that falls under the Sixth Action Programme for the Environment which is based on a practical approach. Natura 2000 The European Union has a rich and very varied natural environment that is of great biological, aesthetic, genetic and economic value. To preserve this natural environment, the EU has taken the initiative with Natura This is an integrated network of protected nature reserves on the territories of he member states. This network forms the cornerstone for EU policy for the preservation and restoration of biodiversity. The network covers all areas that are protected under the Birdlife Directive (1979) and the Habitat Directive (1992). These directives were implemented in the Netherlands in the Nature Conservation Act (Natuurbeschermingswet) of The network is still under construction as not all the member states have definitively designated all the areas. Natura 2000 (Birdlife and Habitat Directive) sets out measures to be taken for species protection. In the Netherlands, these measures are incorporated in the Flora and Fauna Act. The European Commission contributes financially to Natura 2000 s essential protective measures via subsidies such as the LIFE fund. 11

12 Life-nature project Communication Website Waterschap Roer and Overmaas Regional Water Authority has designed a special website to provide residents of Roermond, local people and any other interested parties with information about the project. By regularly adding photographs of the activities, the project can be closely followed from home via the website. (Information) meetings The Regional Water Authority makes information available via meetings and presentations about the project, the reasons for the activities and the progress being made. The target groups were very diverse: there was a meeting for local people and interested parties from Roermond and district, but there were also presentations given to environmental and nature organisations. Excursions The Regional Water Authority organises excursions for groups to sewage treatment installations, walks along streams and soon also to the fish ladders in Roermond. For more information about group excursions, see For more information, please go to If you would like to know more about other water management works or the tasks of Waterschap Roer and Overmaas Regional Water Authority, go to Parklaan 10 Postbus AD Sittard Tel. (046) Fax (046) info@overmaas.nl Foto s: Hugo Jamin e.a. E-zine ontvangen? Wist u al dat het Waterschap Roer en Overmaas een elektronische nieuwsbrief (e-zine) uitgeeft? U kunt u kosteloos abonneren via onze internetsite Klik op digitale nieuwsbrief, vul het formulier in en druk op verzenden.