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 km2 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 km2 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 km2 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 km2 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.

<IP_ADDRESS>. 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.

#### <IP_ADDRESS>. 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

<IP_ADDRESS>. 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.

#### <IP_ADDRESS>. 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.

<IP_ADDRESS>. 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.

<IP_ADDRESS>. 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].

#### <IP_ADDRESS>. 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.

#### <IP_ADDRESS>. 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].

#### <IP_ADDRESS>. 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

Transboundary Cooperation and Sustainable Development in the Rhine Basin

http://dx.doi.org/10.5772/intechopen.73260

145

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

<IP_ADDRESS>. 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].


**Jing Li 1,\*, Keliang Wang 1,\*, Minglei Lian 1, Zhi Li 1 and Tingzhao Du 2**

Received: 24 May 2019; Accepted: 27 June 2019; Published: 1 July 2019

**Abstract:** The separation of aqueous acetonitrile solution by pressure swing distillation (PSD) was simulated and optimized through Aspen Plus software. The distillation sequence of the low pressure column (LPC) and high pressure column (HPC) was determined with a phase diagram. The pressures of the two columns were set to 1 and 4 atm, respectively. Total annual cost (TAC) was considered as the objective function, and design variables, such as the tray number, the reflux ratio, and the feeding position, were optimized. The optimum process parameters were obtained. For the reduction of energy consumption, the PSD with full-heat integration was designed. The TAC of this method is lower by 32.39% of that of the PSD without heat integration. Therefore, it is more economical to separate acetonitrile and water mixture by PSD with full-heat integration, which provides technical support for the separation design of such azeotropes.

**Keywords:** pressure swing distillation; full-heat integration; acetonitrile; water


**7. What are the current views of EU guidelines on all aspects of prolactin?**

Only one set of guidelines, published in 2008, is devoted to prolactin and it provides both advice and the data and rationale behind the consensus group's conclusions (Peveler et al, 2008). Prior to this many guidelines did not give specific recommendations (Citrome et al, 2008). In general terms, other guidelines and relevant Summaries of Product Characteristics do not provide a specific monitoring schedule and tend to advocate prolactin monitoring only when symptoms are detected.

In 2006, guidelines on bipolar disorder from the National Institute of Clinical Excellence recommended limited pre-treatment monitoring of prolactin levels for risperidone with further monitoring should symptoms develop. The only other guideline to recommend pretreatment monitoring are the Maudsley guidelines (Taylor et al, 2009). These guidelines recommend baseline prolactin monitoring, followed up at 6 and 12 months. Furthermore, the guidelines advise switching medications if hyperprolactinaemia is symptomatic or, alternatively, adding aripiprazole. The guidelines also concur broadly that hyperprolactinaemia is associated with both short- and longer term adverse events that include bone mineral density loss and a possible increase in the risk of breast cancer. The 2005 recommendations from the World Federation Society of Biological Psychiatry (WFSBP) curiously conclude that whereas prolactin elevation was frequent with amisulpride and typicals (>10%), it was measured only "sometimes" (<10%) with risperidone (Falkai et al, 2006). Current data now seems to have clarified these frequencies rather differently (Bushe et al, 2010; Bushe et al, 2008). The 2008 UK prolactin guidelines recommend prolactin monitoring in all patients pre-treatment regardless of medication and after 3 months of treatment with a stable dose, in addition to further monitoring when there are relevant clinical symptoms (Peveler et al, 2008). With a normal prolactin level there is no further need for monitoring in the absence of clinical symptoms. Significant dose change should also lead to consideration of further monitoring. These UK guidelines give a clear strategy for investigating the aetiology of hyperprolactinaemia in patients receiving antipsychotics and warn against concluding too easily that antipsychotics are responsible. A differential diagnosis must be considered but must always include a pregnancy test in females and thyroid function tests. Prolactin levels can be elevated to levels in excess of >2000 mIU/L in patients taking antipsychotics, however in any patient with prolactin elevation greater than 3000 mIU/L, a prolactinoma should be considered and referral to an endocrinologist is warranted. In the Halifax cohort we measured prolactin levels >2000 mIU/L in 13% of all antipsychotic-treated females and 2% of males. Antipsychotic cessation even for short

Table 1. Prolactin changes over 24 weeks with depot olanzapine at various dosages in a

**7. What are the current views of EU guidelines on all aspects of prolactin?**

Only one set of guidelines, published in 2008, is devoted to prolactin and it provides both advice and the data and rationale behind the consensus group's conclusions (Peveler et al, 2008). Prior to this many guidelines did not give specific recommendations (Citrome et al, 2008). In general terms, other guidelines and relevant Summaries of Product Characteristics do not provide a specific monitoring schedule and tend to advocate prolactin monitoring

In 2006, guidelines on bipolar disorder from the National Institute of Clinical Excellence recommended limited pre-treatment monitoring of prolactin levels for risperidone with further monitoring should symptoms develop. The only other guideline to recommend pretreatment monitoring are the Maudsley guidelines (Taylor et al, 2009). These guidelines recommend baseline prolactin monitoring, followed up at 6 and 12 months. Furthermore, the guidelines advise switching medications if hyperprolactinaemia is symptomatic or, alternatively, adding aripiprazole. The guidelines also concur broadly that hyperprolactinaemia is associated with both short- and longer term adverse events that include bone mineral density loss and a possible increase in the risk of breast cancer. The 2005 recommendations from the World Federation Society of Biological Psychiatry (WFSBP) curiously conclude that whereas prolactin elevation was frequent with amisulpride and typicals (>10%), it was measured only "sometimes" (<10%) with risperidone (Falkai et al, 2006). Current data now seems to have clarified these frequencies rather differently (Bushe et al, 2010; Bushe et al, 2008). The 2008 UK prolactin guidelines recommend prolactin monitoring in all patients pre-treatment regardless of medication and after 3 months of treatment with a stable dose, in addition to further monitoring when there are relevant clinical symptoms (Peveler et al, 2008). With a normal prolactin level there is no further need for monitoring in the absence of clinical symptoms. Significant dose change should also lead to consideration of further monitoring. These UK guidelines give a clear strategy for investigating the aetiology of hyperprolactinaemia in patients receiving antipsychotics and warn against concluding too easily that antipsychotics are responsible. A differential diagnosis must be considered but must always include a pregnancy test in females and thyroid function tests. Prolactin levels can be elevated to levels in excess of >2000 mIU/L in patients taking antipsychotics, however in any patient with prolactin elevation greater than 3000 mIU/L, a prolactinoma should be considered and referral to an endocrinologist is warranted. In the Halifax cohort we measured prolactin levels >2000 mIU/L in 13% of all antipsychotic-treated females and 2% of males. Antipsychotic cessation even for short

405 mg/month (N=318)

600 mg/month (N=141)

300 mg/month (N=140)

Mean change (micrograms/l) (SD)

randomised controlled trial (Hill et al, 2011)

only when symptoms are detected.

periods has not been clinically recommended due to risk of worsening of the mental state although in theory this could be considered a diagnostic tool for patients taking oral preparations (Peveler et al, 2008).

#### **8. The management of treatment-emergent hyperprolactinaemia**

The management of treatment-emergent hyperprolactinaemia is complex and many of the issues have been considered by the 2008 prolactin guidelines who referenced previous recommendations (Serri et al, 2003). However, newer data have since emerged allowing novel potential management strategies to be considered (Peveler et al, 2008). Levels <1000 mIU/L can simply be monitored but in the presence of symptoms that suggest sex hormone deficiency, it is suggested that such levels should not be allowed to continue long-term due to the potential risk of bone mineral density loss (Peveler et al, 2008). Persistent levels >1000 mIU/L need consideration for medication change or dose reduction, if appropriate. The consensus group concluded that the use of dopamine agonists should be considered only in exceptional circumstances due to the risk of worsening the psychosis (Peveler et al, 2008). This view however is challenged by the Maudsley guidelines (Taylor et al, 2009) which advocate use of dopamine agonists if patients need to remain on the specific prolactinelevating antipsychotic. They make an interesting observation that although the three agents cited (amantadine, cabergoline and bromocriptine ) have the potential to worsen psychosis, that this has not been shown in clinical trials. Although there are many reviews relating to prolactin in the context of severe mental illness, there are currently few, if any, systematic reviews and meta-analyses. A recent systematic review that incorporated a meta-analysis compared the effects of bromocriptine and cabergoline in treating hyperprolactinaemia due to idiopathic causes and prolactinomas (Dos Santos Nunes et al, 2011). They concluded that cabergoline was significantly superior to bromocriptine in normalising both prolactin levels and resuming normal ovulatory cycles. Thus, cabergoline may potentially be the dopamine agonist of choice should this be mandated.

What is currently emerging in an early research phase is the use of specific polypharmacy designed to reduce prolactin levels whilst maintaining treatment on the original antipsychotic. There is little doubt that aripiprazole may have the lowest potential for prolactin elevation, although as we have already stated, in the STAR study 17% of patients did have hyperprolactinaemia (Kerwin et al, 2007 ;Hanssens et al, 2008) although in RCTs, the prevalence rates of 3% seem consistent (Bushe et al, 2008). The combination of adding aripiprazole to risperidone results in significant reductions in plasma concentrations of prolactin of between 35-63%, with maximal benefit measured with aripiprazole doses around 6 mg (Yasui-Furukori, 2010) and possibly doses as low as 3 mg. In 2009, the Maudsley guidelines stated their view that in the presence of symptomatic hyperprolactinaemia options included changing antipsychotics or adding aripiprazole to the existing treatment. As a strategy it is clear that there may be benefit to some patients, however aripiprazole as a partial dopamine agonist has been shown to be associated with worsening of psychosis in some patients. The complete risk-benefit equation for use of aripiprazole in this manner will require further clinical trials. Other salient issues to consider include the reality that schizophrenia the illness, and its associated symptomatology, is the cause of some of the more overt sexual dysfunction (Malik et al, 2011). Reducing prolactin may not always lead to clinical improvement. The correlation between prolactin and sexual dysfunction however is thus complex. In a case series

Prolactin and Schizophrenia, an Evolving Relationship 445

without clinical symptoms, as stated by the authors. Studies suggest that children are more sensitive to the prolactin elevating adverse effects of antipsychotics and care is needed to keep these to a minimum (Correll, 2011). The second high risk group would include those

1. **What are the longer term trajectories of prolactin levels for patients with elevated prolactin?** Research has firmly established that hyperprolactinaemia emerges within days as a consequence of treatment and, as we have shown in a large RCT, equally rapidly reverts to normal with removal of the prolactin-elevating antipsychotic (Bushe et al, 2009). What is less well established is the trajectory of prolactin levels over a longer term period. Do they remain at the same level? Short-term RCTs are unlikely to address this issue and current data that follow patients for 1 year have only reported baseline and endpoint data, not the trajectory of the prolactin response (Schooler et al, 2005). In the absence of a proven mechanism for how and why antipsychotics elevate

2. **What are the longer term outcomes for patients with elevated prolactin?** Over the last 10 years patients receiving biologics to treat rheumatoid arthritis have been entered into voluntary, long-term databases that have addressed, albeit in a naturalistic manner, incidence of potentially associated adverse events (cancers, reactivation of tuberculosis (TB), serious infections). There is a need to formally determine the longer term harm of untreated hyperprolactinaemia in psychiatry. The last decade has better defined potential longer term sequelae of hyperprolactinaemia and these clearly cannot be measured within formal RCTs. In 2011, the clear options involve using either large epidemiological databases, prospectively and retrospectively or creating prospective collections of clinical data such as through usage of registers. The challenge exists in creating appropriate databases that allow long-term follow up of both prolactin levels and clinical outcomes. Certainly the data on bone fractures (Howard et al, 2007; Abel et al, 2008) has shown us the potential. The World Health Organization (WHO) initiated a number of databases to measure cancer rates in schizophrenia in the 1970s (Bushe and Hodgson, 2010) and have the knowledge and ability to conduct similar projects

3. **What is and how can we measure the true risk-benefit of switching antipsychotic treatments**? There is absolute agreement that usage of drugs such as dopamine agonists have significant potential to worsen schizophrenia illness (Peveler et al, 2008). This creates a dichotomy where the clinician can reduce the dose or change the antipsychotic, or do nothing. There is no single pragmatic endpoint that captures this risk. A relatively short-term RCT (1 year or less) looking at formal changes in rating scales, remission levels or relapse rates may be helpful. At a minimum, it may tell us the psychiatric outcome of switching patients from prolactin-elevating antipsychotics compared to maintaining the status quo. It is difficult to see any individual institution or pharmaceutical company undertaking such a complex and expensive study, and the only viable option would be for larger bodies, such as the European Medicines Agency, National Institute of Mental Health or potentially WHO to undertake this

with a relevant strong family history of breast cancer or osteoporosis.

**10. Further research. What are the unanswered questions?**

prolactin differentially (Bushe et al, 2010), one can only speculate.

worldwide relating to outcomes of hyperprolactinaemia.

work.

although all subjects had reduction in prolactin levels, only around half reported improved sexual function (Chen 2011). The reality of the situation is that individual patients will require individual solutions. A physician considering changing an antipsychotic in a stable patient must carefully balance the risks and benefits of continued treatment.

There will be patients who are clearly at high risk of prolactin-related adverse events for whom usage of potentially prolactin-elevating antipsychotics needs to be carefully considered,eg, patients with a history of breast cancer or osteoporosis. The other angle to management is to ensure high screening rates for patients at high risk of treatment-emegent osteoporosis and provision of relevant treatment to potentially reduce fracture incidence (Graham et al, 2011).


Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley Swamp in Sierra Leone, Using SWAT

*Mohamed M. Blango, Richard A. Cooke, Juana P. Moiwo and Emmanuel Kangoma*

## **Abstract**

Many societies have experienced water scarcity resulting from population growth, increased urbanization and industrialization, increased irrigation associated with advances in agriculture productivity, desertification, global warming, or poor water quality. Climate change, and soil heterogeneity has a direct impact on the discharges of many rivers in and around the world. Various hydrological models have been used to characterize the impact of climate and soil properties on hydrology and water resources. The SWAT (Soil and Water Assessment Tool) water balance model, one such model, has been used at a variety of scales. In this instance it was used to model the impact of climate change on water storage in a reservoir at the downstream end of a small (75 ha) watershed. The watershed is the major component of an inland valley swamp, with a valley bottom that receives runoff from the watershed. The SWAT model was calibrated using storage data from 2014/15 and validated with data from 2015/16. Using future ensemble values derived from GCMs, the model predicted a reduction in the storage volume at the beginning of December of every dry season, with the 100-year storage volume down from 10,000 to 6900 cubic meters.

**Keywords:** climate change, micro-dam, inland valley swamp

## **1. Introduction**

Advances in economies and standards of living have resulted in a growing dependency on water resources across the globe. Many societies have experienced water scarcity resulting from population growth, increased urbanization and industrialization, increased energy use, increased irrigation associated with advances in agriculture productivity, desertification, global warming, and poor water quality. Improved understanding of how each of these factors influences water supply, demand, and quality requires an understanding of the underlying processes, and their impact, on water availability and use. Such an understanding is best facilitated by a holistic

approach that integrates hydrologic processes at the watershed scale, to determine an overall watershed response to user demands, changing climates, or both [1].

The circulation of water within the earth and atmosphere is a complex interaction of energy exchange and transportation pathways [2]. Hydrology addresses the waters of the earth, their occurrence, circulation and distribution, their chemical and physical properties, and their reaction with the environment, including their relation to living things. It also deals with the relationship of water with the environment within each phase of the hydrologic cycle. Factors such as rapid urbanization, industrialization and deforestation, land cover change, irrigation, have precipitated changes in hydrologic systems. Climate change, and soil heterogeneity also has a direct impact on the discharges of many rivers. Different hydrologic phenomena and hydrologic cycles need to be thoroughly studied to characterize these impacts.

Various hydrological models have been developed to characterize the impact of climate and soil properties on hydrology and water resources. Each model has its own unique characteristics, but common inputs used by deterministic models include rainfall, air temperature, soil characteristics, topography, vegetation, hydrogeology and other physical parameters. These models can be applied in very complex and large basins [3]. They have been used to simulate water movement under different conditions. They are used to study, *inter alia*, the impact of climate change on water availability, land use change on river discharges, and agricultural management strategies on water availability and sediment yield [2]. Central to this effort, watershed modeling is being utilized as a tool to better understand surface and subsurface water movement and the interactions between these water bodies. More importantly, they offer tools to guide decision making on water resources, water quality, and related hazard issues [1].

Models are a type of tool and are used in combination with many other assessment techniques. Models reflect how watershed systems are conceived. As with any tool, the answers they give are dependent on how they are applied, and the quality of these answers reflects how well the systems are understood. Models are also useful for extrapolating from current conditions to potential future conditions. Indeed, it is not possible to monitor the future, so modeling is the default choice. The ability of models to predict future conditions is very useful for projecting the outcomes of various possible management measures and strategies (http://www.epa.gov/watertrain).

The effect of climate change on water resources can be best handled through simulation of the projected hydrological conditions under such change. Such a treatment is essential as hydrological response is a highly complex process governed by a large number of variables such as terrain, landuse, soil characteristics and the state of the moisture in the soil. The SWAT (Soil and Water Assessment Tool) water balance model is one such model that has been used to carry out the hydrologic modeling of river basins [4].

SWAT is a computationally efficient simulator of hydrology and water quality at various scales. It is a mechanistic continuous model that can handle large watersheds in a computationally efficient manner. The "Hydrologic Unit Model for the United States" (HUMUS) has already been used to simulate river discharges at approximately 6000 gauging stations in the United States, with good results [5–7]. This study was extended within the national assessment of the USDA Conservation Effect Assessment Project (CEAP, (http://www.nrcs.usda.gov/Technical/nri/ceap/ceapgeneralfact.pdf.). SWAT is a comprehensive model that requires a diverse set of input parameters. However, many of the input parameters that are used to simulate special features are not available for all watersheds. SWAT was developed to quantify the impact of land management practices on water, sediment, and agricultural chemical

*Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

yields in large complex watersheds with varying soils, land use, and management conditions, over long periods of time. The main components of SWAT are hydrology, climate, nutrient cycling, soil temperature, sediment movement, crop growth, agricultural management, and pesticide dynamics [8].

Terink et al. [2] described SWAT as a distributed rainfall-runoff model that divides a catchment into smaller discrete calculation units for which the spatial variation of the major physical properties are limited, and hydrological processes can be treated as being homogeneous. The total catchment behavior is a net result of many sub-catchments. Soil and land cover data are used to generate unique combinations within each subcatchment, and each combination is considered as a homogeneous physical entity, called a Hydrological Response Unit (HRU). The water balance for HRUs is computed on a daily time basis. Hence, SWAT disaggregates the river basin into units that have similar characteristics in terms of soil and land cover, and that are located in the same sub-catchment. SWAT is capable of predicting the effects of changes in climate and management conditions on basin hydrology. The model includes many modules, including crop growth, groundwater, and river routing the facilitate the required simulations.

The model is semi-distributed, dividing each subbasin into HRUs based on soil type, crop patterns, and management practices [9]. SWAT has produced favorable model results when evaluated on watersheds with a range of conditions in the U.S. and other countries as diverse as Morocco [2], Finland [10], Pakistan [11] and India [4]. Across many of these watersheds, SWAT has shown flexibility in simulating surface runoff. Gassman et al. [12] found that, because of its core strengths, SWAT is primarily used for calibration and/or sensitivity analysis, climate change impacts, GIS interface descriptions, hydrologic assessments, variation in configuration or data input effects, comparisons with other models or techniques, interfaces with other models, and pollutant assessments. The foundation strength of SWAT in many of these applications is the combination of simplified upland and channel processes that are incorporated into the model [12]. The incorporation of the curve number (CN) method and non-spatial HRUs supports model adaptation to virtually any watershed with a wide variety of hydrologic conditions. With a flexible framework, SWAT facilitates the calculation of Total Maximum Daily Loads (TMDLs) and simulation of a wide variety of conservation practices and other BMPs (e.g., fertilizer and manure application rate and timing, irrigation management, and flood prevention structures). Several studies illustrate the success of SWAT in conducting these types of simulations as part of an overall BMP assessment [1].

The object of this study was to use SWAT to determine the effect of projected climate change on water storage and availability in a small reservoir developed by damming the upper reaches of an inland valley swamp in Sierra Leone. The reservoir is used to grow a second rice crop that extends into the dry season. Information on storage can be used to determine irrigable area under different climate change scenarios.

## **2. Methodology**

#### **2.1 Description of study area**

The study area is a small 75 ha watershed, located at Njala University, in the Southern Province of Sierra Leone. The watershed is a major component of an inland valley swamp, with a valley bottom that receives runoff from the watershed. In a typical swamp, the stream formed in the valley bottom may be perennial, or ephemeral.

The watershed lies between latitudes 8.1140° and 8.1225° North and longitudes 12.0591° and 12.0668° west (**Figure 1**). The mean annual rainfall at Njala is 2200 mm. The annual Reference Evapotranspiration in 2015 and 2016 were 1322.3 and 1395.1 mm respectively.

There are two soils types in the watershed, Pelawahun loam and Njala sloping. Pelewahun soils occur in the drainageways of inland swamps that dissect the higher regions made up of Njala, Mokonde, and Bonjema soils. The terrain is nearly level to depressional, with concave slopes of 1 to 3 percent. Textures are loam to fine sandy loam in the topsoil, changing into clay loam in the upper subsoil, gravelly clay loam in the lower subsoil, and, as the bedrock is approached, clay [13].

## **2.2 SWAT model setup**

SWAT requires data on terrain, land use, soil and weather for assessment of water yield at specified locations in a drainage basin. The selection of scale for spatial data is based on the tradeoff between the availability of required terrain data (in the form of contours data on the topographic maps) and the processing effort required for its

**Figure 1.** *Map of study area.*

*Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

preprocessing using the GIS interface. The following sections provide brief description of data elements used and preprocessing performed on them.

### *2.2.1 Digital elevation model*

A digital elevation model (DEM) is a topographic surface made up of elevation values laid out in a regular grid pattern. The DEM was generated using data from a topographic survey conducted over the watershed. The survey was carried out with the aid of Total station. The x-y-z data were then processed with the Quantum GIS (QGIS) into the DEM. QGIS is a public domain GIS that is free, easy to use, and available for Windows, Apple, and Android computers (http://qgis.org/en/site/). It also has the ability to convert maps between coordinate reference systems on the fly.

### *2.2.2 Delineation of the river basins*

Automatic delineation of the river basins is done by specifying the location of the required final outflow point on the DEM as the final pour/drainage point. The watershed was divided into sub-basins using an arbitrarily selected threshold value. The number of sub basins is a function of this threshold, that controls the drainage density of the automatically constructed drainage system and thereby, the number of sub-basins. The DEM along with the main channels are shown in **Figure 2.**

### *2.2.3 Land cover/land use layer*

Maps that outlined the landuses in the watershed were produced. These maps were stored as shapes files in QGIS, and converted to Comma Separated Variable file (.csv) files for input into SWAT. The entire watershed was split into four different landuses:

**Figure 2.** *Digital elevation model (DEM) with drainage network.*

**Figure 3.** *Land use map for the watershed.*

Grass range (RNCH), mixed forest (BUFL), Water (WATR) and agricultural row crops (AGRC). The land use map for the watershed is shown in **Figure 3.**

## *2.2.4 Soil layer*

A shape file with the various soils in the watershed was also produced. Input tables were prepared, describing various parameters of the soil. These properties include bulk density, particle size distribution, water holding capacity, depth and number of layers of the soil. Two main types of soil were identified in the watershed; Njala sloping (Orthoxic Palehumult) and the Pelewahun loam (Typic Plinthaquult). The soil map is shown in **Figure 4**.

## *2.2.5 Weather data input preparation*

Daily meteorological data were obtained from a WatchDog Weather Station (the 2009 ET Model, Spectrum Technologies Inc., USA) located next to the study area.

The weather input variables required included: solar radiation, wind speed, relative humidity, and precipitation, minimum and maximum temperatures. Weather data from November 2014 through January 2017 were used to calibrate and validate the model. Average data from nine climate change models were used to predict the change in stored water for mid-century (2046–2064) and the end of century (2081–2100).

## *2.2.6 Simulated volume of water in the pond*

In SWAT, ponds and wetlands are impoundments that are located within the subbasin area. The .pnd file contains parameter information used to model the water, *Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

**Figure 4.** *Soil map for the watershed.*

#### **Figure 5.**

*Comparison of 20 years of simulated and historical rainfall for a 20-year period in Sierra Leone.*

sediment and nutrient balance for ponds and wetlands. The key variables in the subbasin pond input file include: surface area (ha) and volume of water (m3 ) in ponds when filled to principal spillway (ha), surface area and volume of water stored in ponds when filled to the principal spillway.

#### *2.2.7 Future climatic data*

For evaluation of the impact of climate change on water quantity, future climate (monthly precipitation and temperature) data were obtained from Bias Corrected and Downscaled WCRP CMIP3 Climate Projections archive for 2046–2064 and 2081–2100 (http://gdo-dcp.ucllnl.org/downscaled\_cmip3\_projections/). Weather and seasonal forecasts show improved reliability and consistency, when the outputs from multiple models are combined. Hence, the averages of nine GCM projections were used (ensemble) to drive the SWAT model in this study, rather than using the outputs from a single GCM.

The models were corrected for bias by comparing data predicted by the models for 1980 to 2000, with observed data from a station in Sierra Leone (**Figure 5**). Mid-century and end of century data produced by the models were then corrected using the ratio of the slopes.

## **3. Result and discussion**

#### **3.1 Pond output data**

The HRU impoundment output file (.wtr) contains summary information for ponds, wetlands and depressional/impounded areas in the HRUs. The file is written in spreadsheet format. The output data include: precipitation falling directly on the pond (PNDPCP) during the time step (mm), the depth of surface runoff entering the pond (PND\_IN) during the time step, evaporation (PNDEVP) from the pond surface during the time step (mm) and volume of water (m3 ) in the pond (PNDVOL) at the end of time step.

#### **3.2 Observed volume of water in the pond**

The stage versus volume of water in the pond plot was used to determine the amount of water in pond at any point in time. A polynomial equation was used to model the relationship between stage (m) and volume of water. The equation was:

$$\mathbf{V} = \mathbf{97}\mathbf{91}\,\mathrm{h}^2 + 2\mathbf{5.818}\,\mathrm{h} - \mathbf{119.05}\,\mathrm{(R}^2 = \mathbf{0.997})\,\mathrm{h}$$

Where, V = Volume of water in pond (m3 ) h = stage (m)

### **3.3 Coefficient of determination (R2) and Nash- Sutcliffe Efficiency (NSE)**

The coefficient of determination (R2 ) for the simulated and observed data of the volume of water in the pond was determined. The NSE was calculated using Eq. (1)

$$NSE = \mathbf{1} - \left[ \frac{\sum\_{i=1}^{n} \left( Y\_i^{obs} - Y\_i^{sim} \right)^2}{\sum\_{i=1}^{n} \left( Y\_i^{obs} - Y^{mean} \right)^2} \right] \tag{1}$$

Where, *Y*i obs is the *i*th observation for the constituent being evaluated, *Y*i sim is the *i*th simulated value for the constituent being evaluated, *Y*mean *mean* is the mean of observed data for the constituent being evaluated, and *n* is the total number of observations.

*Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

### **3.4 Average rainfall for different periods**

The monthly average precipitation totals and average temperatures watershed for the baseline period (1961–2000), mid-century period (2046–2064) and late-century period (2081–2100). The baseline period values were computed using observed data, while the future ensemble values were derived from the GCMs, and corrected for bias, using the ratio of the slopes shown in **Figure 5**. Baseline and projected climate data are shown in **Figure 6**.

### **3.5 Model calibration**

The model was calibrated by minimizing the root mean squared deviation (RMSD) between observed and simulated reservoir storage during the 2014/2015 dry cropping season. The two main factors affecting storage during this period was seepage and evaporation from the reservoir. The most sensitive parameter for evaporation in the model was the PNDEVCOEFF; the ratio of reservoir evaporation to potential evaporation, and PND\_K, the hydraulic conductivity through the bottom of the pond. Both of these parameters were varied over the allowable ranges in the model, and the results were used to develop RSMD contours. These contours are shown in **Figure 7.**

Only certain combinations of the two parameters make physical sense. Under most conditions, PNDEVCOEFF varies between 0.6 and 0.8, with 0.7 being typically used as a default value. In this instance the minina band could not be extended down to these levels, as the model imposes a constraint on the PND\_K, the hydraulic conductivity

**Figure 6.** *Baseline and projected climate data at site.*

**Figure 7.** *RMSD contours of pond evaporation coefficient and hydraulic conductivity.*

through the bottom of the reservoir. This maximum value is suitable for clay soils but is lower than values that are typical for loams, and sandy loams. SWAT was developed for US conditions where ponds are lined with a clay layer or some type of impermeable geotextile material. In this case, however, the bottom of the reservoir was unconsolidated Pelewahun loam. Given the constraints of the model, the calibrated value for PNDEVCOEFF was the value that gave the minimum RMSD value at the maximum allowable value of PND\_K. The relationship between RMSD and PNDEVCOEFF when

**Figure 8.** *RMSD versus pond evaporation coefficient.*

*Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

PND\_K is fixed at 1 mm/hr. is given in **Figure 8**. Based on this figure, 1 mm/hr. and 1.75 were used for PND\_K and PNDEVCOEFF, respectively, in future simulations.

#### **3.6 Model validation**

Using the calibrated values of the coefficient of pond evaporation (PNDEVCOEFF) and hydraulic conductivity of pond (PND\_K), the model was validated against the observed storage volume of 2015/16. The NSE and RMSE values were 0.82 and 1578.2 respectively.

#### **3.7 Storage volume at the start of the dry season**

The storage volumes at the start of December which typically marks the beginning of the dry season were fitted to cumulative distribution functions. The normal distribution was a better fit for 1981/2000, but the log normal better fitted the 2080/2099 period.

The baseline (1980–1999) and end of century periods (2081–2099) were utilized. The baseline data (1980–1999) had negative skewness (−0.09) and kurtosis of 1.22 and the end of century data had a skewness of 2.23 and a kurtosis of 5.89.

## **4. Discussion**

The SWAT model has been found to be computationally efficient in its prediction and very useful because of its original design to assess the role of climate, topography,

soil, and land use in the hydrologic response of a catchment [9, 14]. Several researches have shown satisfactory results in predicting impact of climate change on flows of streams, rivers and reservoirs [11, 15, 16].

In the calibration of the model, two parameters were considered: the coefficient of pond evaporation and the hydraulic conductivity (K). Although, in most cases K values range from 0.6 to 0.8, this parameter was calibrated at the maximum value of 1 for the model, as the model imposes a constraint on the hydraulic conductivity through the bottom of the reservoir. This could be attributed to the difference in soil texture in the bottom of ponds in the US where the model was developed as against the soil type in Sierra Leone for which the model is calibrated. Similarly, Beharry et al. [17] had to modify hydraulic conductivity as a key parameter in the calibration of the SWAT model.

Despite a high RMSE value for validation, the model also produced a good NSE value of 0.82. This indicates the model has a very high power of predicting the stored volume of water in the reservoir at any point in time. **Figure 9** in indicative of a reduction in storage volume of water in the reservoir at any probability level, in the future (2081–2100) as compared to the baseline period (1981–2000). This reduction could be attributed to an increase in evaporation due to high temperatures. This would have a negative impact- reducing the acres of land that can be irrigated. Subsequently, **Figure 9** also indicate that the 100-year storage volume will be reduced from a little over 10,000 m3 during the baseline period to less than 8000 m3 by the end of century (2081–2100). This would imply that designing storage for the dry season could involve less cost as storage volume is predicted to be reduced.

## **5. Conclusion**

Using SWAT, the volume of water stored in a small reservoir was simulated. This was done considering the two main factors affecting storage during this period - seepage and evaporation from the reservoir. The most sensitive parameter for evaporation in the model was the ratio of reservoir evaporation to potential evaporation, and the hydraulic conductivity through the bottom of the pond. The model can be used to predict inflow into dams, water storage and release water management. For evaluation of the impact of climate change on water quantity, future climate (monthly precipitation and temperature) data were obtained from Bias Corrected and Downscaled WCRP CMIP3 Climate Projections archive for 2046–2064 and 2081–2100.

A knowledge of the expected storage volume in the reservoir at the start of the peak dry season is vital for proper planning of supplementary irrigation. Hydrologic modeling tools such as SWAT can help in predicting the hydrologic dynamics of watersheds. However, a challenge to utilizing such a tool will require a calibration process to determine the extent to which parameters can influence the predictive power of the model. The SWAT model was calibrated using the storage volumes of 2014/15 dry season and validated with the 2015/16 dry season data. With future ensemble values derived from the GCMs, the model predicted a reduction in the storage volume at the beginning of December of every dry season, with the 100-year storage volume down from 10,000 m3 to 6900 m3 (**Figure 9**).

The study highlighted the important role that future climate projections would play in understanding the effect of climate change on hydrologic processes. The use of models such as SWAT would be helpful in investigating land use change on nutrient loading and water quality in streams and rivers especially in sub-Saharan countries.

*Modeling the Effect of Climate Change on Water Stored above a Micro-Dam in an Inland Valley… DOI: http://dx.doi.org/10.5772/intechopen.104894*

## **Author details**

Mohamed M. Blango1 \*, Richard A. Cooke2 , Juana P. Moiwo1 and Emmanuel Kangoma1

1 Department of Agricultural Engineering, Njala University, Sierra Leone

2 Department of Agricultural and Biological Engineering, University of Illinois, Urbana-Champaign, USA

\*Address all correspondence to<EMAIL_ADDRESS>
© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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## **Chapter 4**