4. Conservation and rehabilitation of aquatic ecosystems

### 4.1. Ecological balance and ICPR programme "Rhine 2020"

and an assessment of the water quality are summarised and published by the ICPR, from 1956 to 1999 as books and since 2000 on the Internet [14]. In addition to the regular monitoring programmes, the ICPR established a platform for new and upcoming techniques. Since 2015, laboratories in the Rhine catchment using nontarget analysis meet on a regular basis in an expert group. In 2017, the ICPR organised a special monitoring programme including nontarget analysis. This will help to get a better overview over potential pollutants in the Rhine and

In spite of improvements in water quality, a few substances are still detected in too high concentrations. This particularly concerns ubiquitous substances (e.g. mercury), which are persistent and occur almost everywhere in the Rhine catchment [15]. Unfortunately, there are few measures capable of reducing the pollution with these substances on the short run.

Additionally, micro-pollutants are of concern for water quality. There is a diverse group of micro-pollutants, like medicinal products (e.g. carbamazepine) (Figure 7) or odoriferous substances, which are partly not eliminated in the wastewater treatment plants. Very low quantities of these pollutants are detectable in waters and may detrimentally affect life in the Rhine

The active pharmaceutical agents of medicinal products are detected in the Rhine catchment area. The highest concentrations are measured in the Lower Rhine and in tributaries with a high share of municipal wastewater. Wastewater treatment plants have been identified to be a main pathway of input for all therapeutic products for human use and their transformation products. One example of an active pharmaceutical agent in the Rhine catchment area is carbamazepine which is used for the treatment of seizure disorders and neuropathic pain

The Conference of Rhine Ministers (2007) [12] assigned the ICPR to develop a joint and comprehensive strategy for reducing and avoiding micro-pollutant inputs from urban wastewater and diffuse sources into the Rhine and its tributaries by improving knowledge on

Figure 7. Annual average concentrations of carbamazepine from 2007 to 2015 in Weil am Rhein, Koblenz and Bimmen.

its tributaries.

(Figure 7).

and drinking water production.

132 Achievements and Challenges of Integrated River Basin Management

Due to the cooperation of the Rhine-bordering countries within the ICPR, not only the water quality of the Rhine but also its ecological state has further improved. Many intermediate aims for the ecological revalorisation of the Rhine river stated in the "Programme for the Sustainable Development of the Rhine – Rhine 2020" have already been achieved [7, 10, 18]. Besides, the common implementation of the Internationally Coordinated Management Plan 2015 for the IRBD Rhine is currently going on [15].

Alluvial plains of the Rhine are again flooded, oxbow lakes are reconnected to the river and along short stretches the river structures have been ecologically improved. The number of animal and plant species has increased. Since 2006, salmon and other migratory fish may again reach Strasbourg on their way upstream from the North Sea (Figure 8).

The connection of the different habitats along the Rhine from Lake Constance to the sea in order to achieve habitat patch connectivity is successful. In this connection, the ICPR sets definite targets and spatial focal points aimed at linking water protection with nature and

Figure 8. Atlantic salmon (source: Ulrich Haufe, AugenBlick Naturfilm).

flood protection. In spite of the success achieved, the ecological functionality of the comprehensive Rhine system is not yet satisfactory.

This result was achieved by improved wastewater treatment (as mentioned in Part 3) and more river continuity. Figure 9 shows the development of the average oxygen content and of the

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However, today's biological diversity in the Rhine is different from that in former times, as many new species have settled, which will remain part of the future water system. Measures aimed at restoring waters and removing obstacles to migration will favour indigenous species

Alluvial areas are essential for the Rhine ecosystem as they represent valuable nature resources and act as natural flood buffers. They increase water retention and are thus important means of flood prevention (see also Part 5). Reactivating floodplains along the Rhine and reconnecting alluvial waters are two important measures aimed at ecologically upgrading the Rhine [18]. Such ecological support is required, as numerous river training measures along the Rhine and almost all tributaries have basically modified the hydrological and morphological conditions. For example, cutting off more than 85% of the alluvial areas along the Upper and Lower Rhine has led to

The ICPR programme "Rhine 2020" for a sustainable development of the Rhine includes targets to reactivate 160 km<sup>2</sup> of floodplain along the Rhine and in the lowlands of the Rhine

invertebrate communities in the Rhine at the German-Dutch border.

great losses of habitats and of animal and plant species typical for the Rhine.

Figure 10. Reactivation of floodplains between 2000 and 2012.

and strengthen the ecosystem.

4.3. Alluvial areas

Above all, the ecological continuity of the Rhine from Lake Constance to the sea and of its tributaries must be further improved. Further targets are to increase the structural diversity of the banks of the Rhine and its arms and the extension of alluvial areas [7, 10]. With a view to restoring the ecological continuity of the Rhine and its tributaries, the ICPR has drafted a "Master Plan Migratory Fish Rhine" [19].

#### 4.2. Fauna and flora

Many hundreds of animal and plant species live in the innumerable different habitats along the Rhine and its tributaries (Figure 8). The presence of a particular species permits conclusions regarding the ecological state of the habitat. Therefore, some fish typical of a specific habitat and other water organisms serve as indicators for the ecological state. Plankton and water fowl also play an important role.

The ICPR regularly publishes summary reports on all biological analysis results of the 6-year monitoring cycle [18]. The last biological inventories showed that with a number of 64 species in the Rhine, the range of fish species is almost complete again [18]. Apart from fish, the Rhine fauna consists of worms, mussels, snails, crustaceans, insects, birds and mammals. From the Alpine Rhine until the North Sea, more than 500 invertebrate species—called macrozoobenthos—were detected on the bed of the Rhine. Many water plant species have also returned to the Rhine. Thus, the ecological network is in a distinctly better state than in the 1980s.

Figure 9. Development of the invertebrate communities of the Rhine and average oxygen content of the Rhine at Emmerich (Lower Rhine).

This result was achieved by improved wastewater treatment (as mentioned in Part 3) and more river continuity. Figure 9 shows the development of the average oxygen content and of the invertebrate communities in the Rhine at the German-Dutch border.

However, today's biological diversity in the Rhine is different from that in former times, as many new species have settled, which will remain part of the future water system. Measures aimed at restoring waters and removing obstacles to migration will favour indigenous species and strengthen the ecosystem.

#### 4.3. Alluvial areas

flood protection. In spite of the success achieved, the ecological functionality of the compre-

Above all, the ecological continuity of the Rhine from Lake Constance to the sea and of its tributaries must be further improved. Further targets are to increase the structural diversity of the banks of the Rhine and its arms and the extension of alluvial areas [7, 10]. With a view to restoring the ecological continuity of the Rhine and its tributaries, the ICPR has drafted a

Many hundreds of animal and plant species live in the innumerable different habitats along the Rhine and its tributaries (Figure 8). The presence of a particular species permits conclusions regarding the ecological state of the habitat. Therefore, some fish typical of a specific habitat and other water organisms serve as indicators for the ecological state. Plankton and

The ICPR regularly publishes summary reports on all biological analysis results of the 6-year monitoring cycle [18]. The last biological inventories showed that with a number of 64 species in the Rhine, the range of fish species is almost complete again [18]. Apart from fish, the Rhine fauna consists of worms, mussels, snails, crustaceans, insects, birds and mammals. From the Alpine Rhine until the North Sea, more than 500 invertebrate species—called macrozoobenthos—were detected on the bed of the Rhine. Many water plant species have also returned to the Rhine. Thus,

Figure 9. Development of the invertebrate communities of the Rhine and average oxygen content of the Rhine at

the ecological network is in a distinctly better state than in the 1980s.

hensive Rhine system is not yet satisfactory.

134 Achievements and Challenges of Integrated River Basin Management

"Master Plan Migratory Fish Rhine" [19].

water fowl also play an important role.

4.2. Fauna and flora

Emmerich (Lower Rhine).

Alluvial areas are essential for the Rhine ecosystem as they represent valuable nature resources and act as natural flood buffers. They increase water retention and are thus important means of flood prevention (see also Part 5). Reactivating floodplains along the Rhine and reconnecting alluvial waters are two important measures aimed at ecologically upgrading the Rhine [18]. Such ecological support is required, as numerous river training measures along the Rhine and almost all tributaries have basically modified the hydrological and morphological conditions. For example, cutting off more than 85% of the alluvial areas along the Upper and Lower Rhine has led to great losses of habitats and of animal and plant species typical for the Rhine.

The ICPR programme "Rhine 2020" for a sustainable development of the Rhine includes targets to reactivate 160 km<sup>2</sup> of floodplain along the Rhine and in the lowlands of the Rhine

Figure 10. Reactivation of floodplains between 2000 and 2012.

and 1000 km2 in the entire Rhine watershed as well as to renature 11,000 km of flowing waters by 2020. Furthermore, 100 old water courses of the Rhine and backwaters are to be reconnected by 2020. A first balance revealed that the intermediate targets set for 2005 had been achieved and that progress continues. By 2012, about 122 km<sup>2</sup> of alluvial areas along the Rhine had been reactivated and 80 old water courses of the Rhine and backwaters had been reconnected (Figure 10) [7, 10, 18].

#### 4.4. Habitat patch connectivity

In order to maintain an ecological continuity, biotopes along the Rhine must again be interconnected. Once the connected habitats of the Rhine and its tributaries present an ecological continuity, animals may move up- and downstream (see also Section 4.5 on migratory fish), and plants may be carried away by the currents. After eventual extreme situations, such as floods and low water periods, they may recolonise up- or downstream sections from lateral waters. Therefore, habitat patch connectivity is a very important functional characteristic of the Rhine ecosystem which will serve water protection, nature protection as well as flood protection. The sum of all measures will also support the increase of biodiversity in the ecosystems of the Rhine. For these reasons the re-establishment of the habitat patch connectivity along the Rhine from Lake Constance to the North Sea is one of the targets set by "Rhine 2020" and is also part of the report and the atlas of the ICPR for achieving a habitat patch connectivity along the Rhine [20–22].

#### 4.5. Importance of ecological continuity for migratory fish

Restoring the ecological continuity of the Rhine from Lake Constance to the North Sea and that of priority tributaries for recolonisation is also a distinct target of the ICPR "Master Plan Migratory Fish Rhine" [19]. The Master Plan is supposed to indicate how self-sustaining, stable migratory fish populations can again be settled in the Rhine watershed as far as the Basel area within both reasonable time and at reasonable costs.

During their life cycle, anadromous long-distance migratory fish like salmon (spawning in fresh water) and the catadromous eel (spawning in marine waters) migrate from the sea into fresh water or from fresh water into the sea for the purpose of reproduction (Figure 11).

Formerly, the Rhine catchment used to be an important habitat for migratory fish. However, since the nineteenth century, systematic river training, e.g. for navigation and hydropower uses, on the Upper and High Rhine and along many tributaries has heavily interfered with ecological continuity in the Rhine system (see Part 4.3). Transverse structures, such as weirs or barrages, may seriously interfere with or completely obstruct migration in a water body. Spawning grounds and juvenile fish habitats of migratory fish have partly been destroyed and are no longer accessible, or their accessibility is considerably reduced.

5. Reducing the impacts of water quantity issues (floods, low flows)

Figure 12. Improvement of river continuity between 2000 and 2012.

Figure 11. Life cycle of migratory fish Atlantic salmon.

The topography of the Rhine catchment varies and includes different climatic zones (alpine, low mountainous, Atlantic, semi-continental climate). Different discharge regimes are overlapping: a "snow regime" in the southern part near the Alps with flood events mainly occurring in summer (snow melt) and low water periods mainly in winter. Waters draining the Central Upland region (Neckar, Main, Nahe, Lahn, Moselle, etc.) are characterised by a "pluvial regime" with prevailing

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Due to the implementation of the Master Plan Migratory Fish Rhine, ecological continuity has been improved at more than hundreds of barrages, e.g. by constructing fish passes (Figure 12), and in 2015, 21% of the salmon spawning grounds were again accessible. Since about the year 2000, annually several hundreds of salmon again migrate upstream to the Upper Rhine and reproduce naturally in the accessible salmon waters [23].

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Figure 11. Life cycle of migratory fish Atlantic salmon.

and 1000 km2 in the entire Rhine watershed as well as to renature 11,000 km of flowing waters by 2020. Furthermore, 100 old water courses of the Rhine and backwaters are to be reconnected by 2020. A first balance revealed that the intermediate targets set for 2005 had been achieved and that progress continues. By 2012, about 122 km<sup>2</sup> of alluvial areas along the Rhine had been reactivated and 80 old water courses of the Rhine and backwaters had been reconnected

In order to maintain an ecological continuity, biotopes along the Rhine must again be interconnected. Once the connected habitats of the Rhine and its tributaries present an ecological continuity, animals may move up- and downstream (see also Section 4.5 on migratory fish), and plants may be carried away by the currents. After eventual extreme situations, such as floods and low water periods, they may recolonise up- or downstream sections from lateral waters. Therefore, habitat patch connectivity is a very important functional characteristic of the Rhine ecosystem which will serve water protection, nature protection as well as flood protection. The sum of all measures will also support the increase of biodiversity in the ecosystems of the Rhine. For these reasons the re-establishment of the habitat patch connectivity along the Rhine from Lake Constance to the North Sea is one of the targets set by "Rhine 2020" and is also part of the report and the atlas of the ICPR for achieving a habitat patch connectivity along the Rhine [20–22].

Restoring the ecological continuity of the Rhine from Lake Constance to the North Sea and that of priority tributaries for recolonisation is also a distinct target of the ICPR "Master Plan Migratory Fish Rhine" [19]. The Master Plan is supposed to indicate how self-sustaining, stable migratory fish populations can again be settled in the Rhine watershed as far as the Basel area

During their life cycle, anadromous long-distance migratory fish like salmon (spawning in fresh water) and the catadromous eel (spawning in marine waters) migrate from the sea into fresh water or from fresh water into the sea for the purpose of reproduction (Figure 11).

Formerly, the Rhine catchment used to be an important habitat for migratory fish. However, since the nineteenth century, systematic river training, e.g. for navigation and hydropower uses, on the Upper and High Rhine and along many tributaries has heavily interfered with ecological continuity in the Rhine system (see Part 4.3). Transverse structures, such as weirs or barrages, may seriously interfere with or completely obstruct migration in a water body. Spawning grounds and juvenile fish habitats of migratory fish have partly been destroyed

Due to the implementation of the Master Plan Migratory Fish Rhine, ecological continuity has been improved at more than hundreds of barrages, e.g. by constructing fish passes (Figure 12), and in 2015, 21% of the salmon spawning grounds were again accessible. Since about the year 2000, annually several hundreds of salmon again migrate upstream to the Upper Rhine and

and are no longer accessible, or their accessibility is considerably reduced.

reproduce naturally in the accessible salmon waters [23].

(Figure 10) [7, 10, 18].

4.4. Habitat patch connectivity

136 Achievements and Challenges of Integrated River Basin Management

4.5. Importance of ecological continuity for migratory fish

within both reasonable time and at reasonable costs.

Figure 12. Improvement of river continuity between 2000 and 2012.

#### 5. Reducing the impacts of water quantity issues (floods, low flows)

The topography of the Rhine catchment varies and includes different climatic zones (alpine, low mountainous, Atlantic, semi-continental climate). Different discharge regimes are overlapping: a "snow regime" in the southern part near the Alps with flood events mainly occurring in summer (snow melt) and low water periods mainly in winter. Waters draining the Central Upland region (Neckar, Main, Nahe, Lahn, Moselle, etc.) are characterised by a "pluvial regime" with prevailing winter floods and low flows in summer. Since these two regimes overlap, the downstream discharge distribution over the year is uniform ("combined regime") [24, 25].

Furthermore, climate change consequences for the discharge lead to more homogenous runoff in the south, while the seasonal distribution becomes more marked in the north. These tendencies continue during the twenty-first century, and, due to reduced runoff in summer, they might even be intensified (Figure 13) [25, 26]. Together with land settlement and man-made water works, this is already now resulting in diverse flood and low flow patterns.

As stated in Part 2, the two catastrophic flood events on the Rhine in 1993 and 1995, causing, respectively, 1.4 and 2.6 billion euros damages, were the starting point for the ICPR to deal with quantitative issues and flood risk (Figure 14) [6, 7]. Because of several low flow events since the 2000s and their negative impacts, the Rhine Ministers decided in 2013 to address this issue and undertake an in-depth analysis of low flows and their consequences (Figure 15) [12]. Apart from that, the ICPR is working on the topic of climate change effects on the water regime and the water quality and environment (Figure 13). Since 2015, the ICPR has published a first Climate Change Adaptation Strategy for the Rhine Basin based on hydro-climatic observations and measurements from the twentieth century and scenarios for the twenty-first century [25, 27]. The different working groups of the ICPR (dealing with water quality, ecology, flood and low water) have made a thematic assessment of the respective consequences and proposed actions which have been integrated into the strategy.

The focus in this subchapter will be on flood risk management, as low water has just begun to be treated within the ICPR. Interesting results about low water change, repercussions, etc. will be available in the upcoming years.

Figure 14. 1995 Flood in Cologne, Germany (source: Stadtentwässerungsbetriebe Köln).

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Figure 15. 2015 Low water in Koblenz, Germany.

#### 5.1. Transboundary flood risk management

Since 1998, the ICPR has implemented the Action Plan on Floods [6, 7] which set out four action targets: reduce damage, water levels, improve flood forecast and risk awareness. Since 2007 it has established a framework for the exchange of information and coordinated implementation of the European Floods Directive (FD) within the IRBD Rhine [28].

Figure 13. Possible effects of climate change on discharges in the near and far future (Cologne).

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Figure 14. 1995 Flood in Cologne, Germany (source: Stadtentwässerungsbetriebe Köln).

Figure 15. 2015 Low water in Koblenz, Germany.

winter floods and low flows in summer. Since these two regimes overlap, the downstream

Furthermore, climate change consequences for the discharge lead to more homogenous runoff in the south, while the seasonal distribution becomes more marked in the north. These tendencies continue during the twenty-first century, and, due to reduced runoff in summer, they might even be intensified (Figure 13) [25, 26]. Together with land settlement and man-made

As stated in Part 2, the two catastrophic flood events on the Rhine in 1993 and 1995, causing, respectively, 1.4 and 2.6 billion euros damages, were the starting point for the ICPR to deal with quantitative issues and flood risk (Figure 14) [6, 7]. Because of several low flow events since the 2000s and their negative impacts, the Rhine Ministers decided in 2013 to address this issue and undertake an in-depth analysis of low flows and their consequences (Figure 15) [12]. Apart from that, the ICPR is working on the topic of climate change effects on the water regime and the water quality and environment (Figure 13). Since 2015, the ICPR has published a first Climate Change Adaptation Strategy for the Rhine Basin based on hydro-climatic observations and measurements from the twentieth century and scenarios for the twenty-first century [25, 27]. The different working groups of the ICPR (dealing with water quality, ecology, flood and low water) have made a thematic assessment of the respective consequences and proposed

The focus in this subchapter will be on flood risk management, as low water has just begun to be treated within the ICPR. Interesting results about low water change, repercussions, etc. will

Since 1998, the ICPR has implemented the Action Plan on Floods [6, 7] which set out four action targets: reduce damage, water levels, improve flood forecast and risk awareness. Since 2007 it has established a framework for the exchange of information and coordinated imple-

mentation of the European Floods Directive (FD) within the IRBD Rhine [28].

Figure 13. Possible effects of climate change on discharges in the near and far future (Cologne).

discharge distribution over the year is uniform ("combined regime") [24, 25].

water works, this is already now resulting in diverse flood and low flow patterns.

actions which have been integrated into the strategy.

138 Achievements and Challenges of Integrated River Basin Management

be available in the upcoming years.

5.1. Transboundary flood risk management

The objectives of the FD concern the management of flood risk in order to reduce potential adverse consequences of floods for human health, the environment, cultural heritage and economic activities. The Directive stipulates extensive cooperation in the field of flood management in international river basin districts. Based on the principle of solidarity, the states should avoid taking measures which, due to their extent and their effect, increase the flood risk in other countries upstream or downstream in the same river catchment as long as these measures are not coordinated between the member states concerned and no common solution has been found.

In accordance with the FD, different common products (reports, maps) have been drafted and published on the ICPR homepage, among others, the first overriding Flood Risk Management Plan (FRMP) (2016–2021) for the Rhine basin (see measures of the FRMP in Part 5.1.2) [28]. The measures of the FRMP Rhine are currently being implemented by the states themselves, and discussions have started to prepare the second FRMP (2022–2027).

#### 5.1.1. Principles and targets of the FRMP

Consistent with the APF [6] and the FD, the Rhine states have determined common principles for the FRMP:


These principles are translated into four overriding, general targets representing the whole flood risk management cycle (prevention, protection, preparedness, crisis management and recovery) (Figure 16). Relying on these targets, the states have decided joint measures presented in Section 5.1.2.

effects. Furthermore, according to the WFD and FD, some measures, e.g. retention areas, have to

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As stated in the Conference of Rhine Ministers (2013), and due to the effects of climate change and the expected increase of the number of flood events, supra-regional flood risk management measures such as keeping flood-prone areas free from further uses or creating more flood retention areas and more room for the river are increasingly important. Therefore, the Ministers decided the further and consequent implementation of all measures aimed at lowering water levels or of retention measures along the Rhine planned until 2020 within the framework of the

The following measures aiming at lowering water levels are related to the latter and are included in the FRMP (Figure 17): future retention areas, dike relocation, renaturing (Figure 10) and keeping discharge corridors free (see Part 4). For the further measures, the securing of the

According to an ICPR study [7, 29], a reduction of flood peaks will be achieved once all planned measures will have been implemented (Figure 18). The results permit a substantiated evaluation of the effectiveness of measures implemented and of their contribution to achieving

be coordinated or present synergies between the goals of the FD and the WFD.

surfaces under aspects of spatial planning is being determined in the FRMP.

5.1.2.2. Implementation of measures aimed at lowering the water levels

Figure 16. Overarching targets and simplified risk management cycle.

APF (Figure 17).

the objectives of the FRMP.

#### 5.1.2. Presentation of joint measures of the FRMP

The FRMP for the Rhine basin describes measures with transboundary effects and measures, for which an exchange of information and an international coordination between the states in the Rhine catchment are important. The FRMP Rhine also includes information and links to the national and regional FRMPs.

#### 5.1.2.1. International coordination of measures

The EU member states in the Rhine catchment are in charge of implementing the FD and apply the principles of subsidiarity and solidarity. In order to respect these provisions, the states, Länder and regions within the IRBD Rhine have agreed not to increase flood risks outside their respective territories. To this end, they will effectively coordinate measures with transboundary Transboundary Cooperation and Sustainable Development in the Rhine Basin http://dx.doi.org/10.5772/intechopen.73260 141

Figure 16. Overarching targets and simplified risk management cycle.

The objectives of the FD concern the management of flood risk in order to reduce potential adverse consequences of floods for human health, the environment, cultural heritage and economic activities. The Directive stipulates extensive cooperation in the field of flood management in international river basin districts. Based on the principle of solidarity, the states should avoid taking measures which, due to their extent and their effect, increase the flood risk in other countries upstream or downstream in the same river catchment as long as these measures are not coordinated between the member states concerned and no common solution

In accordance with the FD, different common products (reports, maps) have been drafted and published on the ICPR homepage, among others, the first overriding Flood Risk Management Plan (FRMP) (2016–2021) for the Rhine basin (see measures of the FRMP in Part 5.1.2) [28]. The measures of the FRMP Rhine are currently being implemented by the states themselves, and

Consistent with the APF [6] and the FD, the Rhine states have determined common principles

• Responsibility, solidarity, proportionality and clear task distribution (between the states

These principles are translated into four overriding, general targets representing the whole flood risk management cycle (prevention, protection, preparedness, crisis management and recovery) (Figure 16). Relying on these targets, the states have decided joint measures presented in

The FRMP for the Rhine basin describes measures with transboundary effects and measures, for which an exchange of information and an international coordination between the states in the Rhine catchment are important. The FRMP Rhine also includes information and links to the

The EU member states in the Rhine catchment are in charge of implementing the FD and apply the principles of subsidiarity and solidarity. In order to respect these provisions, the states, Länder and regions within the IRBD Rhine have agreed not to increase flood risks outside their respective territories. To this end, they will effectively coordinate measures with transboundary

• Synergy with other EU environmental politics (specially the WFD; see Parts 3 and 4).

• The security level has to be ecologically, economically and socially compliant.

discussions have started to prepare the second FRMP (2022–2027).

5.1.1. Principles and targets of the FRMP

when it comes to flood risk management).

140 Achievements and Challenges of Integrated River Basin Management

• Sustainable and integral flood risk management.

• No 100% security, always residual risks.

5.1.2. Presentation of joint measures of the FRMP

5.1.2.1. International coordination of measures

national and regional FRMPs.

has been found.

for the FRMP:

Section 5.1.2.

effects. Furthermore, according to the WFD and FD, some measures, e.g. retention areas, have to be coordinated or present synergies between the goals of the FD and the WFD.

#### 5.1.2.2. Implementation of measures aimed at lowering the water levels

As stated in the Conference of Rhine Ministers (2013), and due to the effects of climate change and the expected increase of the number of flood events, supra-regional flood risk management measures such as keeping flood-prone areas free from further uses or creating more flood retention areas and more room for the river are increasingly important. Therefore, the Ministers decided the further and consequent implementation of all measures aimed at lowering water levels or of retention measures along the Rhine planned until 2020 within the framework of the APF (Figure 17).

The following measures aiming at lowering water levels are related to the latter and are included in the FRMP (Figure 17): future retention areas, dike relocation, renaturing (Figure 10) and keeping discharge corridors free (see Part 4). For the further measures, the securing of the surfaces under aspects of spatial planning is being determined in the FRMP.

According to an ICPR study [7, 29], a reduction of flood peaks will be achieved once all planned measures will have been implemented (Figure 18). The results permit a substantiated evaluation of the effectiveness of measures implemented and of their contribution to achieving the objectives of the FRMP.

5.1.2.3. Improved exchange of information and access to information

resulting in an overall damage or risk assessment.

prove to be most efficient (Figures 17 and 18) [31, 32].

Figure 19. Rhine Atlas (flood hazard and flood risk maps).

evolution

supports the implementation of preventive measures in flood-prone areas.

5.1.2.4. Instrument for the assessment of the impact of flood risk management measures on risk

The ICPR, supported by the engineering consultant HKV, developed the instrument "ICPR FloRiAn (Flood Risk Analysis)" aimed at evaluating the effect of measures to reduce flood risk and at estimating the future evolution of flood risk. The instrument, working in a consistent, reproducible and transparent manner, is available on demand at the ICPR and is applicable to other river basins [31, 32]. ICPR FloRiAn is GIS based and in the case of the ICPR covers the main stream of the Rhine. Flood maps (e.g. developed under the FD) are the basis for the tool. In addition to the quantification of economic flood risk, modules are developed for quantifying the consequences of risk for human health, to the environment and to culture heritage. In short, the main instrument consists of three interacting calculation modules (Model Builders)

The ICPR uses this tool to assess risk reduction and evolution along the Rhine from 1995 up to now as well as to carry out regular reviews of the impacts of measures on flood risk reduction for the FRMP. Calculations made with the help of ICPR FloRiAn proved—among other results—the reduction of flood risks by 25% between 1995 and 2020 for economic activities. Under a supraregional aspect, measures increasing water retention in the direct vicinity of the Rhine river

The mutual exchange of information on flood risk management is done at the ICPR level. The population is also being well informed on a national, regional or local scale, so that regional specifics may be taken into account. The "Rhine Atlas" [33] is a supranational sensitisation tool comprising aggregated flood hazard and risk maps (Figure 19). For the main stream of the Rhine, flood depth and areas as well as objects at risk are shown for three scenarios (high, medium and low flood probability). Additional information and more detailed national maps are available by clicking on any area of the atlas. Together with uses adapted to floods, it also

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Figure 17. Example of measures aimed at lowering water levels: retention basin and dike relocation (source: Regierungspräsidium Freiburg—Integrated Rhine Programme (2011)).

Figure 18. Possible reduction of flood peaks due to measures lowering the water level (State 2010 and 2020).

The reduction of water levels by different corresponding measures along the Rhine (Figure 18) may equally lead to reduced flood probability [29, 30]. This also results in a reduction of flood risks. The results of this study [30] were used for calculating the modification of flood risk with the GIS instrument [31, 32].

#### 5.1.2.3. Improved exchange of information and access to information

The mutual exchange of information on flood risk management is done at the ICPR level. The population is also being well informed on a national, regional or local scale, so that regional specifics may be taken into account. The "Rhine Atlas" [33] is a supranational sensitisation tool comprising aggregated flood hazard and risk maps (Figure 19). For the main stream of the Rhine, flood depth and areas as well as objects at risk are shown for three scenarios (high, medium and low flood probability). Additional information and more detailed national maps are available by clicking on any area of the atlas. Together with uses adapted to floods, it also supports the implementation of preventive measures in flood-prone areas.

#### 5.1.2.4. Instrument for the assessment of the impact of flood risk management measures on risk evolution

The ICPR, supported by the engineering consultant HKV, developed the instrument "ICPR FloRiAn (Flood Risk Analysis)" aimed at evaluating the effect of measures to reduce flood risk and at estimating the future evolution of flood risk. The instrument, working in a consistent, reproducible and transparent manner, is available on demand at the ICPR and is applicable to other river basins [31, 32]. ICPR FloRiAn is GIS based and in the case of the ICPR covers the main stream of the Rhine. Flood maps (e.g. developed under the FD) are the basis for the tool. In addition to the quantification of economic flood risk, modules are developed for quantifying the consequences of risk for human health, to the environment and to culture heritage. In short, the main instrument consists of three interacting calculation modules (Model Builders) resulting in an overall damage or risk assessment.

The ICPR uses this tool to assess risk reduction and evolution along the Rhine from 1995 up to now as well as to carry out regular reviews of the impacts of measures on flood risk reduction for the FRMP. Calculations made with the help of ICPR FloRiAn proved—among other results—the reduction of flood risks by 25% between 1995 and 2020 for economic activities. Under a supraregional aspect, measures increasing water retention in the direct vicinity of the Rhine river prove to be most efficient (Figures 17 and 18) [31, 32].

Figure 19. Rhine Atlas (flood hazard and flood risk maps).

The reduction of water levels by different corresponding measures along the Rhine (Figure 18) may equally lead to reduced flood probability [29, 30]. This also results in a reduction of flood risks. The results of this study [30] were used for calculating the modification of flood risk with

Figure 18. Possible reduction of flood peaks due to measures lowering the water level (State 2010 and 2020).

Figure 17. Example of measures aimed at lowering water levels: retention basin and dike relocation (source: Regierung-

spräsidium Freiburg—Integrated Rhine Programme (2011)).

142 Achievements and Challenges of Integrated River Basin Management

the GIS instrument [31, 32].

#### 5.1.2.5. Improve flood forecasting and warning systems as well as crisis management

Flood forecasting and flood announcement contribute to reducing damage in case of a flood event [7, 31, 32]. Therefore, the states, Länder and regions in the IRBD Rhine—through national centres along the Rhine (Figure 20)—cooperate at an international level when exchanging data on discharge and precipitation and using them for flood forecasting [34]. The quality of information and forecasting is continuously being improved. Today, national mobile applications like "Meine Pegel" or "KATWARN" disseminate information and warn on water levels or storms

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Good crisis management planning for flood events is important in order to be able to reduce risks during the event. The ICPR has begun to compile existing multilateral crisis management systems and the understanding of national disaster risk reduction. If necessary, this exchange of information will enable improvements in this domain. This also applies to recovery measures.

Just as floods, low flows are natural, evident events that cannot be avoided. However, low water may considerably restrict navigation on the Rhine. The performance of hydropower plants may equally be reduced in times of low discharge. Besides, low flows can go hand in hand with high temperatures, leading to reduced oxygen content which may detrimentally impact the ecosystem. The Rhine states are therefore paying increased attention to the topic of low flows. In 2017, the ICPR (Expert group "Low water") has begun to analyse the trend of low water since the beginning of the twentieth century, to examine past low flow events and classify them in return periods. The ICPR is investigating the various consequences of low water for different uses of the Rhine. It is furthermore working on the inventory of national

low water management measures as well as on low water monitoring.

(Figure 21) [35, 36].

5.2. The issue of low flows

Figure 21. Mobile application "Meine Pegel" [35].

Figure 20. Flood forecasting centres along the Rhine.

on discharge and precipitation and using them for flood forecasting [34]. The quality of information and forecasting is continuously being improved. Today, national mobile applications like "Meine Pegel" or "KATWARN" disseminate information and warn on water levels or storms (Figure 21) [35, 36].

Good crisis management planning for flood events is important in order to be able to reduce risks during the event. The ICPR has begun to compile existing multilateral crisis management systems and the understanding of national disaster risk reduction. If necessary, this exchange of information will enable improvements in this domain. This also applies to recovery measures.

#### 5.2. The issue of low flows

5.1.2.5. Improve flood forecasting and warning systems as well as crisis management

144 Achievements and Challenges of Integrated River Basin Management

Figure 20. Flood forecasting centres along the Rhine.

Flood forecasting and flood announcement contribute to reducing damage in case of a flood event [7, 31, 32]. Therefore, the states, Länder and regions in the IRBD Rhine—through national centres along the Rhine (Figure 20)—cooperate at an international level when exchanging data

> Just as floods, low flows are natural, evident events that cannot be avoided. However, low water may considerably restrict navigation on the Rhine. The performance of hydropower plants may equally be reduced in times of low discharge. Besides, low flows can go hand in hand with high temperatures, leading to reduced oxygen content which may detrimentally impact the ecosystem. The Rhine states are therefore paying increased attention to the topic of low flows. In 2017, the ICPR (Expert group "Low water") has begun to analyse the trend of low water since the beginning of the twentieth century, to examine past low flow events and classify them in return periods. The ICPR is investigating the various consequences of low water for different uses of the Rhine. It is furthermore working on the inventory of national low water management measures as well as on low water monitoring.

Figure 21. Mobile application "Meine Pegel" [35].
