The aim of river restoration is to return rivers and streams to their natural state and to improve their ecological status. Potential actors for river restoration measures are towns and municipalities, water management authorities, water maintenance associations, fishing associations and citizens' initiatives.
In many German rivers, the objectives of the European Water Framework Directive (WFD) were not achieved by 2015. For this reason, deadline extensions and exemptions were claimed for almost 92 percent of all German surface water bodies (BMU/UBA 2016). Nutrient pollution, hydromorphological pressures and inadequate implementation of river restoration measures are main causes of the deficient status of many water bodies in Germany (UBA 2017).
Consequently, hydromorphological improvements account for the largest share (41.5 %) of the measures planned by the German federal states in the WFD management cycle 2016-2021 (BMU/UBA 2016). The states largely rely on the cooperation and voluntary actions of local stakeholders when it comes to implementing restoration measures. The awareness and priority given to river restoration by local stakeholders should be strengthened because the future status of German rivers depends on how much attention is paid to rivers today.
River restoration is about the sustainable development of water bodies. Natural and near-natural watercourses have many advantages, e.g.:
They increase the quality of life as landscape-forming elements in urban and rural areas.
They reduce the risk of flooding for downstream users.
They provide habitats for numerous plant and animal species.
They support the degradation of environmentally harmful substances (e.g. wastewater, fertilisers).
They contribute to adaptation to global climate change.
Near-natural river Rur
The Rur near Monschau in North Rhine-Westphalia is a typical near-natural mountainous river. With its diverse riverbed and banks, it provides habitats for a large number of plant and animal communities.
Source: Georg Lamberty / Planungsbüro Zumbroich
Restored section of the rural river Wuemme with its riparian corridor (2012)
Largely restored rivers such as the Wuemme in Lower Saxony serve as ecological corridors in the cultural landscape. Riparian buffer strips with trees and shrubs separate the river from adjacent agricultural areas and act as important buffers against the input of pollutants.
Source: Wolfgang Kundel (terra-air services) / Landkreis Verden
Cycling on the restored Ruhr near Binnerfeld (2018)
The restoration of the Ruhr near Arnsberg (North Rhine-Westphalia) offers new habitats for animals and plants, and new opportunities for people to experience nature. Those seeking recreation can use the foot and cycle paths along the restored river and gain a varied insight into nature.
Source: Marco Linke / Medieningenieurbüro Manntau
Restored river Murg in Rastatt, Baden-Wuerttemberg (2018)
Since its restoration, the river Murg in Rastatt has been able to develop self-dynamically within the dyked area. This also makes it more attractive for local recreation.
Source: Marco Linke / Medieningenieurbüro Manntau
Ecological upgrading of a stream in an urban area
Even heavily straightened and constricted water bodies in the city can be ecologically upgraded by restoring the riverbed and banks.
Human uses cause damages, pressures and modifications of water bodies
Humans have always used and altered watercourses and floodplains for a wide variety of objectives, including land reclamation for settlements and food production, energy generation, drinking water supply, flood protection, discharge of treated wastewater, transport and recreation. In order to make these diverse uses possible, considerable interventions are necessary in the rivers and their surroundings. These interventions can lead to a reduced diversity of biotopes and species and even to the destruction of sensitive ecosystems.
Watercourses are often straightened, constricted or channelized and their floodplains are used or sealed right up to the riverbanks. These anthropogenic modifications affect the natural processes in the water body, flow velocity increases and the water retention of the floodplain is reduced. These processes cause rivers to incise and to loose connection to their floodplains: diverse habitats become monotonous channels. Excessive water withdrawal or input of pollutants through the discharge of wastewater or the inflow of fertilisers and pesticides from agriculture place an additional burden on watercourses.
Straightened creek in Hesse
This water body was embanked and straightened to a monotonous channel. It is no longer connected to its floodplain. Therefore, natural flood retention has been impeded.
Source: Georg Lamberty / Planungsbüro Zumbroich
Embankment wall of a creek in Bonn (North Rhine-Westphalia)
No room for dynamic river development remains between these completely modified banks and the intensively built-up floodplain.
Source: Georg Lamberty / Planungsbüro Zumbroich
Piped section of a stream
Bed and banks of this water body in North Rhine-Westphalia have been heavily modified through piping. No natural structures remain.
Source: Georg Lamberty / Planungsbüro Zumbroich
Anthropogenic alteration of the Spree floodplain in Berlin
In the Spree River floodplain in Berlin, the government district has been developed up to the riverbanks. Habitats for plants and animals are no longer existent.
Source: Georg Lamberty / Planungsbüro Zumbroich
Weir with backwater at the Regen river in Bavaria
Obstacles like this weir impede fish migration. The damming also changes the seasonal water dynamics.
Restoration measures improve the ecological status of rivers
The aim of river restoration is to develop rivers and streams towards a near-natural state. However, this does not mean that restoration can fully achieve a natural state. For every restoration measure, the natural reference conditions are compared with what is feasible and a realistic development goal is set.
Generally, river restoration should use a river's dynamics instead of reconstructing it, because every construction measure interferes with the aquatic ecosystem. In most cases, an initial measure is required to trigger river dynamics towards a near-natural state. Examples of initial measures are the removal of built-up embankments and bed fixation.
Measures for river restoration
Bulldozers are not always needed to restore a river. Lively waters manage their restoration themselves when space for development is provided and initiating measures trigger the dynamics of a river. If the watercourse cannot be changed, small measures can still considerably improve the structure of a river. Over 90% of German rivers and streams are straightened, constricted, piped or interrupted by structures such as weirs or barrages. Restoration can improve the ecological status and attractiveness of water bodies.
1/4 - If obstacles interrupt the river’s continuity:
2/4 - If the watercourse cannot be changed:
3/4 - If river profile and banks can be changed:
4/4 - If large-scale development is possible:
Initial measure to start restoration at the Fulda river in Hesse (2018)
Often, a relatively small measure is sufficient to trigger river dynamics. At the Fulda, stones were installed diagonally into the riverbed to divert the water flow. As a result, the riverbank on the opposite side began to erode, and the river started to develop.
Source: Georg Lamberty / Planungsbüro Zumbroich
Decaying river bank protection made of natural materials at a creek in Lower Saxony (2018)
During the restoration of the creek Schierenbach, wood has been used for bank protection. This natural material decays over time and slowly allows the water body to develop. In addition, the decomposing wood serves as food for numerous insect larvae.
Source: Georg Lamberty / Planungsbüro Zumbroich
Restored Ruhr in Oeventrop shortly after completion of the construction work (2018)
A richly structured river section has been created in Oeventrop (North Rhine-Westphalia) by flattening the riverbanks. This also provides river access to the local population.
Source: Marco Linke / Medieningenieurbüro Manntau
Construction measure to restore the river Dhuenn (2003)
Initial construction measures were necessary to restore the river estuary of the Dhuenn in North Rhine-Westphalia. In Leverkusen, the Dhuenn flows into the Wupper river, which immediately flows into the Rhine.
Source: Thomas Zumbroich / Planungsbüro Zumbroich
Small initial measure with large effect
Initiated by a trunk acting as a groyne, the water has excavated a scour and deposited a gravel bank: two habitats for fish and benthic invertebrates.
Source: Werner H. Baur
The river Nebel between Dobbin and Linstow in Mecklenburg during restoration work (2013)
Natural elements, such as dead wood, were introduced into the river. The objective is to promote river dynamics and to improve habitat diversity.
Planning, funding and participation are vital for successful river restoration
Sustainable river development is a complex undertaking. Clear restoration objectives must be defined, different interests must be balanced and various legal requirements must be taken into account. Well-structured planning and project management is necessary for a successful and efficient implementation of measures.
Depending on the type of restoration project, the costs can be very high. Therefore, the German federal states and the European Union offer numerous funding and financing programmes. In addition, river restoration projects can be used as compensatory measures in the context of impact regulation under nature protection law. Foundations and sponsors can also be considered. With a clever combination of several financing instruments, restoration projects can be financed up to 100 %.
Administrations, water management authorities, water maintenance associations, non-profit organisations, farmers and the local population (i.e. many stakeholders) are involved in river restoration projects. This can lead to conflicts, especially when it comes to the provision of land for water restoration projects. The executing agency should communicate with all involved parties at an early stage and in all planning phases. All stakeholders should be given the opportunity to participate. This promotes mutual understanding, creates acceptance and provides planning security for all.
Planning and implementation of restoration projects
The project schedule for river restoration projects can vary greatly. This flow chart shows the most important project steps. Natural river development is a complex undertaking. A well-structured planning management creates the prerequisites for a balanced solution and an efficient and successful implementation of measures.
River restoration costs money, but there are many funding instruments and grants that can be combined. In addition, compensatory measures and overlapping interests with other departments and stakeholders (e.g. flood protection, nature conservation) can be utilised.
River restoration in the context of different interests
Many interests come together when considering rivers. For restoration projects, new compromises must be reached and conflicts of use must be resolved through planning processes. Early, open and regular communication between all stakeholders increases the satisfaction with the restoration result.
The contents above are translated excerpts of an online platform on river restoration that has been created by the German Federal Environment Agency (UBA). The platform seeks to motivate stakeholders to start river restoration projects. It has been designed for representatives of towns and municipalities, water management authorities, water maintenance associations, fishing associations, citizens' initiatives, etc.
The online platform is written in German and offers information on:
Ten examples of river restoration projects across Germany where a wide variety of measures were implemented. This section includes many videos and photos that are worth watching even if you don’t understand German!
The UBA’s motto, For our environment (“Für Mensch und Umwelt”), sums up our mission pretty well, we feel. In this video we give an insight into our work.
The UBA
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