deltares trends & responses of 8 deltas

Towards sustainable development of deltas, estuaries and coastal zones

Trends and responses

Towards sustainable development of deltas, estuaries and coastal zones

Trends and responses

January 21, 2009

Contents

Preface 5

1. Trends and issues in the development of deltas 7 1.1 Deltas: economic and environmental hot spots 7 1.2 Deltas: melting-pot of drivers and trends 9 1.3 Issues at stake in deltas 11 1.4 Conceptual view on planning of delta development 18 1.5 A closer look at some societal trends 19 1.6 Linking responses to drivers and trends 21

2. Management and restoration of natural systems 23 2.1 Functions and values of deltas 23 2.2 Natural coastal protection and wetland restoration 31 2.3 Integrity of ecosystems: biodiversity, environmental flows 33 2.4 Room for rivers 37 2.5 Multiple use of wetlands 39

3. Extension and revitalization of infrastructure 41 3.1 Role of infrastructure in delta development 41 3.2 Infrastructure to support economic development 43 3.3 Rehabilitation of infrastructure 48 3.4 New approaches in design of infrastructure 50

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4. Development and adaptation of land and water use 57 4.1 Modes in adaptation of land and water use 57 4.2 Spatial planning and zoning 58 4.3 Urban (re)development 60 4.4 Adaptation to flood risks 62 4.5 New agricultural practices to adapt to salinity problems 63 4.6 Adaptation to climate change 64

5. Governance of delta development and management 69 5.1 Role of governance in delta development 69 5.2 Co-operation between levels and sectors of government 71 5.3 Cooperation between government and private sector 77 5.4 Involvement of stakeholders and citizens 80 5.5 Approaches for dealing with risks and uncertainties 83

6. Way forward? 87 6.1 Two conflicting perspectives on development of deltas 87 6.2 Enabling the sustainable development of deltas 90 6.3 Delta vision: a shared view on delta development 91 6.4 Delta technology: innovations in science and technology 92 6.5 Delta governance: social and institutional innovations 93 6.6 Delta dialogue: establishing best delta practices 94

References 97

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This research on deltas, estuaries and coastal zones is part of the preparation of the Aquaterra 2009 Conference and the World Forum on Delta and Coastal Development. Deltas may be defined as low-lying areas where a river flows into a sea or lake. A delta is often considered a different type of river mouth than an estuary, although the processes shaping deltas and estuaries are basically the same. In line with the scope of the Aquaterra Conference we have adopted in this research a broad interpretation of deltas which includes deltas proper, estuaries and the adjacent coastal zone.

Deltas are areas with major economic potential as well as large environmental values. The challenge for sustainable development of deltas is to strike a balance between economic development and environmental stewardship. The Aquaterra Conference will present and discuss the state and future of deltas worldwide, with a special focus on eight selected deltas. All these selected deltas are densely populated and/or economically developed.

• Yellow River Delta (China)• Mekong River Delta (Vietnam)• Ganges–Brahmaputra Delta (Bangladesh)• Ciliwung River Delta (Indonesia)• Nile River Delta (Egypt)• Rhine River Delta (The Netherlands)• Mississippi River Delta (USA)• California Bay Delta (USA)

Another focus of the Aquaterra Conference is the response in deltas to a number of drivers such as economic growth and climate change as well as to a number of trends in society such as privatization and decentralization. Four response themes are being considered:• Natural systems (management and restoration)• Infrastructure (extension and revitalization)• Land and water use (development and adaptation)• Governance (of delta development)

The research has explored the perspectives of and experiences with these response themes. Some of these responses may already be classified as ‘best

Preface

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practices’ or better ‘good ideas’ (at least in the local context), others are yet promising approaches. Anyway, the research aims to provide an overview of current practices in dealing with delta issues.

An effort has been made to arrange these practices into global trends. Trends which are illustrated with examples taken from deltas all over the world, with an emphasis on the eight selected deltas of the Aquaterra Conference and in particular the Rhine River Delta. The examples presented are not necessarily the best illustrations of the trends. Own experiences of the researchers as well as easy access to information have played a role in the selection of examples. However, taken together, the trends and examples provide a comprehensive overview of the type of current activities and developments to enable delta life.

The focus of the research has been on the identification of issues, trends and responses. The outcome is still qualitative and descriptive. It may be viewed as a first step in the description and analysis of state and future of deltas worldwide. It may be worthwhile to elaborate on the current research. Such elaboration may include a more rigorous assessment of the functioning of deltas based on a set of indicators. Also an extension to other deltas should be included. This might be a nice challenge for future Aquaterra Conferences.

Delft, January 2009

Prof. dr. Huib de Vriend, Director Science, Deltares

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1.1 Deltas: economic and environmental hot spots

The major rivers systems of the world all have a unique delta region, with their specific challenges and opportunities. But there are also common characteristics. Deltas are usually areas with major economic potential because of their strategic location close to seas and inland waterways. Deltas provide also some of the world’s most fertile lands important for food production. That is why navigation and port development, oil production and refinery as well as agriculture and fisheries have always been the engines of economic development of deltas.

Attracted by these potentials, large numbers of people live in deltas; a development which has led to the growth of coastal (mega-)cities. Population growth and economic development make extensive demands on the available natural resources and trigger pollution. If not properly managed deltas may easily turn into sinks in the frontier between continents and oceans.

1. Trends and issues in the development of deltas

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Trends and issues in the development of deltas

The rivers that flow through the deltas are an important source of fresh water and nutrients that are critical for sustaining life in the deltas. The mixing of salt and fresh water in the estuarine part of the deltas creates environmental conditions for a unique flora and fauna. Delta and estuarine ecosystems are therefore valuable and among the most productive ecosystems on earth.

But, being low-lying areas, deltas are also vulnerable to flooding and have to cope with stagnating drainage. That is why living in deltas has always required human intervention. Land reclamation, irrigation, soil drainage and embankments have made many a delta a safe place to live and work.

Box 1.1

Opportunities of deltas Challenges in deltas

• strategic location close to seas and water ways• high potential for port development and oil

industry• fertile soils and rich aquatic environment• large potential for agriculture and fisheries• valuable and most productive ecosystems

• areas vulnerable to flooding and drought• human intervention needed to safely live and

work• filter or sink for upstream pollution• areas with high pressure on available space

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1.2 Deltas: melting-pot of drivers and trends

Population growth, economic development and climate change are the main drivers for change in deltas. These developments pose extensive demands on the available natural resources of deltas. In addition to these drivers there are a number of societal trends which affect the organization and outcome of planning of delta development. The main drivers and trends are briefly described in Box 1.2.

Of these trends decentralization and privatization may be viewed as autonomous developments. The challenge is to utilize the advantages of both trends, while minimizing their undeniable drawbacks. This calls for a selective enhancement of governance structures, reflecting the regional scale, integrated nature and long term perspective of delta development.

Nile delta

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Box 1.2

Drivers for change Trends in society

population growth: the global population still grows with some 2% per year, although there are distinct regional differences. The number of people to be served and to be protected against natural hazards will increase.

decentralization: brings delta issues closer to the stakeholders involved. Due to lack of national coordination there is, however, a sincere risk of uncontrolled and/or chaotic developments.

economic development: despite the current economic recession, economic growth may be expected over larger periods of time, resulting in larger demands to be met, higher values to protect, more energy to be generated and more goods to be transported.

privatization: public-private partnerships are becoming the modus operandi for new infrastructural projects and services. Increased efficiency of tax payer’s money is a key motive. The risk of privatization, however, is a focus on the short term as well as a neglect of the public interest.

climate change: although the extent of climate change may be subject of debate, there is general consensus that rise of global temperature is inevitable, with its associated (local) impacts on sea level rise and the hydrological cycle (larger and more frequent droughts and floods)

participation: involvement of stakeholders and citizens is important to promote societal support of development projects as well as maintenance of infrastructure; planning may benefit from the tacit knowledge of stakeholders

technological development: innovations may open opportunities to enhance the functionality of infrastructural solutions, to extend the life time of infrastructure and/or to develop more cost-effective designs

environmental concerns: worldwide concern over a changing climate and environmental degradation has raised the environmental awareness; it influences the valuation of impacts and the choice of measures

risk aversion: acceptance of risk is decreasing in our modern societies; hence considerable efforts are made to further reduce or control the risks of natural hazards

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1.3 Issues at stake in deltas

Overview of pressing delta issuesThe characteristics, which make deltas attractive areas to live and work, are under stress. Available space is under pressure, vulnerability to flooding is increasing, fresh water resources are threatened, etc. Population growth, economic development and climate change will cause additional stress on deltas, unless appropriate measures are taken. The main issues at stake in deltas are briefly described in Box 1.3

Box 1.3

Main issues at stake in deltas

Pressure on available space: being a focal point of economic development population density is generally high and further rising. Coastal mega-cities have developed; their size and number are growing.

Vulnerability to flooding and drought: being low-lying areas, deltas are vulnerable to flooding. Subsidence of soft soils adds to this vulnerability. Accumulation of people and wealth will further increase the vulnerability with respect to climate change.

Shortages of freshwater resources: many deltas in the world currently face water shortages. Climate change may result in more frequent and prolonged periods of low river discharges. This will have profound repercussions on the delta agriculture, as well as on delta and coastal ecosystems.

Ageing or inadequacy of infrastructure: many deltas have irrigation and drainage systems which require an upgrade or major revision to improve their effectiveness. Other deltas have inadequate flood protection schemes or schemes that will require major upgrading.

Erosion of coastal areas: many deltas face a sediment shortage. This sediment shortage is often caused by regulation works in the upstream river. The sediment shortage causes coastal erosion problems. Sea level rise will aggravate these erosion problems.

Loss of environmental quality: Ecosystem functioning and biodiversity in deltas is under very high pressure worldwide. Main causes are a high population density and concentration of industrial, harbor and mining activities. Deltas are also receptor of pollutants from upstream.

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Importance of issues in the eight selected deltasThe Aquaterra Conference will present and discuss the state and future of deltas worldwide, with a special focus on eight selected deltas:

1. Yellow River Delta (China)2. Mekong River Delta (Vietnam)3. Ganges–Brahmaputra delta (Bangladesh)4. Ciliwung River Delta (Indonesia)5. Nile River Delta (Egypt)6. Rhine River Delta (The Netherlands)7. Mississippi River Delta (USA)8. California Bay (USA)

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In the research a quick assessment has been made whether the delta issues are a minor or major problem in these deltas. Box 1.4 displays to what extent issues play a role. The classification distinguishes four types of problems. Problems are judged minor if they are either unimportant, small in magnitude or well controlled (•). A minor problem can become bigger in future (e.g. due to climate change or delta developments) in which case it is given two bullets (••). An issue is classified as a currently big problem if the issue is requiring significant management attention and is not (yet) controlled (•••). If the problem is likely to increase in the near future it is given four bullets (••••).

Box 1.4

issues

deltas pressure on

space

flood

vulnerability

freshwater

shortage

ageing or

inadequate

infrastructure

coastal

erosion

loss of

environmental

quality and

biodiversity

Yellow River Delta (China)

•• • •• • ••• •••

Mekong River Delta (Vietnam)

•• •••• •••• •• • •••

Ganges–Brahmaputra Delta (Bangladesh)

•••• •••• •• •• •••• ••••

Ciliwung River Delta (Indonesia)

•••• •••• •• •• • ••••

Nile River Delta (Egypt)

•••• • •••• •••• •• ••

Rhine River Delta (The Netherlands)

••• •• •• ••• •• •

Mississippi River Delta (USA)

• •••• • •••• •••• ••••

California Bay (USA)

•• •••• •••• ••• • •••

Legend:

• relatively minor problem, now and in the near future

•• currently a minor problem, but is likely to increase in the near future

••• currently already a big problem, future trend uncertain

•••• currently already a big problem, likely to increase in the near future

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Brief explanation of assessmentsThe assessments presented in Box 1.4 reflects our current understanding of the issues at stake in the eight deltas and may need revision once more information becomes available. A short explanation of the reasoning behind the assessment is presented underneath. The separate delta descriptions provide further background on the issues.

Yellow River Delta (China)

pressure on space: With a relatively low population density (210 inhabitants/km2 in the rural area) this issue is not urgent

vulnerability to flood: Flood risk is relatively low: the river is fully embanked and there is no storm surge hazard

freshwater shortage: Although minimum flows for the delta are guaranteed, future climate change is likely to reduce overall water availability in the river basin

ageing infrastructure As the delta and its occupation is of recent date, ageing of infrastructure does not play an important role yet

coastal erosion: Especially along the northern coast erosion is a big problem due to sediment starvation

loss of biodiversity: Nature Protection areas along the coast are under high pressure of limiting freshwater and economic activities (esp. from the oil industry)

Mekong River Delta (Vietnam)

pressure on space: The population density is 410 inhabitants/km2 and with a growth rate of 2.5% per year, pressure on space will increase in future

vulnerability to flood: Floods are a common feature of the delta and society has learned to live with it.

freshwater shortage: During low flows salinity intrusion is a recurrent problem, likely to increase with sea level rise. Groundwater use is growing.

ageing infrastructure The delta has an extensive canal and embankment system, some of which over 100 years old

coastal erosion: The sediment balance of the Mekong river is, compared to other major Deltas, relatively stable

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loss of biodiversity: The Delta has an extremely rich biodiversity which is under pressure due to the rapid economic growth

Ganges–Brahmaputra Delta (Bangladesh)

pressure on space: With some 1500 inhabitants/km2 the delta is one of the most densely populated regions on earth.

vulnerability to flood: Most of the delta is prone to tropical cyclones with high storm surges.

freshwater shortage: Due to upstream developments and climate change, critical low flow conditions of rivers are likely to increase

ageing infrastructure Management of embankments and irrigation system is a recurrent problem

coastal erosion: Annual rate of erosion is ± 10,000 ha and accretion is only 2,500 ha.Erosion is a bigger problem than flooding.

loss of biodiversity: Especially the mangrove forests (Sundarbans) are highly valuable but also under high pressure from encroachment and exploitation.

Ciliwung River Delta (Indonesia)

pressure on space: Jakarta is the fourth largest urban area in the world (23 million inhabitants)

vulnerability to flood: Almost half of the area is below sea level and is still subsiding. The city is prone to inundation due to excessive rainfall and flash floods

freshwater shortage: Land conversion from forest to agriculture and urban area results in water shortages during the dry season.

ageing infrastructure Although much of the infrastructure is relatively recent, rehabilitation is needed, esp. with respect to drainage systems

coastal erosion: Locally there is coastal erosion due to natural and man-made factors. Islands in the Bay are disappearing as a result of coral reef destruction

loss of biodiversity: Water quality is a major issue as many upstream domestic and industrial waste water is discharged untreated.

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Nile River Delta (Egypt)

pressure on space: With half of Egypt’s population of 80 million living in the delta and a population growth rate of nearly 2% pressure on available space is the main issue of the Nile Delta

vulnerability to flood: River floods are minimized through the High Dam and coastal storms are rather mild.

freshwater shortage: The entire country is dependent on Nile water inflow. As demands continue to rise, freshwater shortage will increase in the future.

ageing infrastructure The extensive irrigation system is stretched to its limits; there is a constant need for efficiency improvement

coastal erosion: Due to Aswan dam most of the Nile sediments are trapped in Lake Nasser. Sediment balance at the coast is disturbed, leading to coastal erosion

loss of biodiversity: As the bird-rich coastal lagoons are at the end of the system, their water quality is threatened by salinization and pollution.

Rhine River Delta (The Netherlands)

pressure on space: With a population density of around 500 inhabitants/km2 the delta is densely populated which implies a high pressure on space

vulnerability to flood: Although the flood risk is quite small, potential consequences of a flood are high. Future sea level rise and growing investments will increase flood risk.

freshwater shortage: Rising sea levels will increase the problem of salt water seepage and will cause local freshwater shortages.

ageing infrastructure The sophisticated infrastructure will require adaptation to new conditions induced by climate change.

coastal erosion: Coastal erosion is well controlled with extensive sand nourishments. Sea level rise will increase the maintenance nourishments needs

loss of biodiversity: The health of estuarine and coastal ecosystems is compromised by pollution and reduced hydrodynamics. Plans are underway to improve the situation.

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Mississippi River Delta (USA)

pressure on space: The population is not very dense, less than 100 inhabitants/km2.

vulnerability to flood: The delta is recurrently visited by hurricanes. The flood protection system requires upgrading.

freshwater shortage: As yet there is no serious shortage of freshwater in the Delta.

ageing infrastructure There is a high investment need to upgrade the flood protection and navigation (the Mississippi River Gulf Outlet, MRGO) system. The MRGO is a former federal navigation channel opened in 1968 to provide a short route between the Port of New Orleans and the Gulf of Mexico.

coastal erosion: Soil subsidence, canal construction and wave exposure have led to huge land loss. Likely to increase due to sea level rise.

loss of biodiversity: Wetlands are disappearing at an alarming rate since decades.

California Bay (USA)

pressure on space: Pressure on the available space is currently not a major issue. But population growth rates in the Delta are projected to be higher than in the state as a whole.

vulnerability to flood: Most of the delta is below sea level. Sea level rise, earthquake hazard and subsidence will increase vulnerability. Large scale flooding of the Delta with saline water could have immense consequences for the entire state.

freshwater shortage: Nearly two-thirds of the state’s population depend on the Delta for at least some of their water supply. The delta experienced severe droughts in the past. Limited opportunities to increase supply.

ageing infrastructure Delta infrastructure started to develop as from 1850. Because of shifting demands it requires constant updating and maintenance.

coastal erosion: The delta itself does not have a coast. In the wider region (San Francisco Bay) several beaches suffer from erosion

loss of biodiversity: The Delta is in an ecological tailspin. Invasive species, water pumping facilities urban and agricultural pollution are degrading water quality and threatening multiple fish species with extinction.

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The main purpose of the overview of Box 1.4 is to show that there is quite some variation between the eight deltas. For example vulnerability to flooding is a major issue in most deltas but not in all. The table also shows that some deltas have to deal with a range of major issues, whereas in other deltas most issues are minor or at least under control. Although some individual assessments may need further study , this will not alter the overall picture.

1.4 Conceptual view on planning of delta development

The delta issues described have something in common: they reflect development of land and water use and development of infrastructure which was not sustainable. In other words the developments were not in harmony with the limitations and potentials of natural systems. To analyze the sustainable development of deltas a framework of analysis is needed. In this research the so-called ‘Layer modeli has been adopted (see Figure 1.1). The Layer model divides the space in three physical planning layers, each with their own dynamics. These layers are the base layer (water and soil), the network

Figure 1.1 Layer model for planning of delta development

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layer (infrastructure) and the occupation layer (physical pattern arising from human activities: living, working, recreating; in short: land and water use).

The essence of the Layer model is the difference in dynamics and vulnerability between the layers, which results in a logical order in planning the various layers. The layers enable and/or constrain activities in another layer.

The Layer model may be instrumental in for example the design of strategies for adaptation to climate change. The key to adaptation to climate change (climate proofing) lies in the base layer. If the structure of the base layer is climate proof, then the other layers follow suit. This is not a matter of hierarchy or dominance but of logical order: the base layer first.

The climate proofing of the base layer is the sole responsibility of government. The way to act is to make maximum use of the large adaptive capacities of natural systems. Moving to the occupation layer the role and influence of government becomes more restricted and the influences of private parties and citizen’s interests become more dominant.

1.5 A closer look at some societal trends

PrivatizationIn many countries governments tend to pull away from ownership and management of infrastructure. The central government increasingly plays a role of coordinating networks and markets and organizing supervision (Broekhans & Correljé, 2008). Public-private partnerships are becoming more and more the modus operandi for new infrastructural projects. Utility sectors, such as railways, electricity and drinking water have been privatized in many countries. Increased efficiency of tax payer’s money is a key motive for this development. But that does not mean that there is no role left for the central government. Indeed, in order to safeguard public values in the liberalized utility sectors, authorities are installed that oversee quality and guaranteed delivery of goods and services.

Another form of privatization is the handover of land (and water) that was previously owned and managed by the government. Examples can be found in Eastern European and some Asian countries. These countries are now under transition from a previously communist regime to a more democratic

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and capitalist economy. This transition has often increased the much needed agricultural productivity, but also created new ‘tragedies of the commons’. For instance, in Vietnam, liberalization of market forces and privatization of coastal resources has led to serious cases of overexploitation (Kleinen; Adger & Luttrell, 2000). A case study from the Red River Delta revealed that privatizing water management institutions does not necessarily mean a better management of water (Fontenelle, 2000).

DecentralizationDecentralization of planning and management is visible in many countries as well. For example in India decentralization is taking place through the Panchayat system (i.e. local government bodies at the village level). There can be different reasons for downscaling management and planning at more regional and local levels: e.g. reduction of government bureaucracy, increased empowerment and participation of local stakeholders, state budget constraints and political motivations. Although most people generally agree that it is better to decide and manage at the lowest possible level (e.g. subsidiary principle: the idea that a central authority should have a subsidiary function, performing only those tasks which cannot be performed effectively at a more immediate or local level (Wikipedia, accessed on 3 December 2008), this does not mean that this goes without any problems. For instance, a study on the decentralized management of fishery and wetland resources on the Kerala Coast (India), concluded that ‘fisheries is the big looser in the local self-governance system’ (Panday, 2003). Although intentions are often good, the elaboration of clear roles and human capacity are often the bottleneck.

Global environmental concernGlobal climate change poses both risks and opportunities: worldwide concern over a changing climate and environmental degradation has raised an environmental awareness that was not seen before. The Intergovernmental Panel on Climate Change, the UN Millenium Development Goals, global conventions on biodiversity, wetlands and transboundary pollution and the World Water Forum are but a few of the examples that exemplify this awareness. This leads to the notion by many people that human society needs to adapt to the (limiting) carrying capacity of the environment, i.e. the ‘base layer’ in our conceptual model.

Dealing with these trendsThese trends pose tremendous challenges to delta management. Existing

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management approaches and tools are not always adequate as they tend to tackle these challenges in a piecemeal and sector wise way. For example, in many countries a full fledged Environmental Impact Assessment legislation is operational. Although this is a great improvement over past practices neglecting the negative consequences of development projects, it mostly does not account for multiple and cumulative impacts. Also planning regulations and limitations do not always serve an optimal spatial development. And sometimes even are counter effective. For instance, hazard regulations that could promote risk reduction in the long run, could turn into vehicles for short-term and short-sighted economic gain. We see this in communities that rush to issue permits before the publication of new maps that show that the area to be built in is vulnerable to an increased or changed flood hazard (Armstrong, 2000). It has also been long standing knowledge that nature conservation by means of protective areas or reserves has significant limitations. Endangered species get trapped in those isolated havens as their habitat becomes unsuited due to climate change.

These are but some examples of the difficulties delta management is confronted with. As a way out, a more holistic and integrated view on delta management is getting shape. We see this for instance in integrated water management, coastal zone management and at the scale of entire river basins. But there is more: ideas to reconcile human development with nature are emerging in various fields. ‘Building with Nature’ is practiced already in the form of beach nourishments as opposed to hard structures to control erosion. Multifunctional use of infrastructure is being implemented in densely populated deltas, to save space and money. Restoring the natural purification capacity of wetlands and estuaries are being considered in highly modified deltas, as in the Netherlands. Renewable energy from waves, tides and salinity gradients is being studied.

Decentralization and privatization may be viewed as autonomous developments. The challenge is to utilize the advantages of both trends, while minimizing their undeniable drawbacks. This calls for a selective enhancement of governance structures, reflecting the regional scale, integrated nature and long term perspective of delta development.

1.6 Linking responses to drivers and trendsTo promote sustainable development of deltas a clear vision has to be developed on how to respond to the various drivers of change as well as on how to play along

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with the various trends in society. A strategy for sustainable development of deltas cannot be limited to infrastructural measures or restoration measures for natural systems. A sensible combination of different kind of responses is required. This should include measures for management and restoration of natural systems, for development and adaptation of land and water use and for extension and revitalization of infrastructure. Furthermore enhancement of the governance structure is required to enable implementation of these responses. These are in fact the four major response themes distinguished in the Aquaterra 2009 Conference (see Figure 1.2). The first three response themes reflect the three layers of the conceptual planning model.

The research has explored the perspectives of and experiences with these response themes. Some of these responses may already be classified as ‘best practices’, others are yet promising approaches. Anyway, the research provides an overview of current practices in dealing with delta issues. An effort has been made to arrange these practices into trends. These trends are discussed by response theme in the next sections.

Figure 1.2 Linking response themes to drivers and trends

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2.1 Functions and values of deltas

Delta processes: shaping the base layerDeltas are relatively young landforms shaped by the interplay of coastal and riverine processes. For example the entire Yellow River Delta was formed in a period of slightly more than century. Since 1855, when the Yellow River shifted its course from debouching in the Yellow Sea towards flowing into the Bohai Sea, each year up to several thousands of hectares of new land was formed (Liu & Drost, 1996). This rapid expansion of the delta is thanks to the enormous

2. Management and restoration of natural systems

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Management and restoration of natural systems

quantities of sediment transported by the Yellow River from the extensive Loss plateaux and from which the river has received its name. Although the Yellow River is quite exceptional in its sediment load, all other deltas have been formed by the sediments brought in by their respective river and shaped by the interplay of tides, waves and currents. At the seaside of a delta, these forces tend to erode and disperse the sediments. But as long as the net input of sediments exceeds the rate of erosion, the delta will grow. This brings us to the first important observation: these natural processes are crucial in the long term evolution of a delta. A net deficit in sediment supply will lead to coastal erosion and – hence – could lead to problems in the human use of the delta base layer.

Besides sediments, the river also constantly supplies the delta with fresh water, nutrients and organic matter. When the freshwater mixes with the seawater, flocculation leads to rapid settling down of small particles and produces an extremely nutrient rich aquatic environment. For this reason the delta estuaries and its marine environs have the highest biological production of all natural areas in the world. From this wealth, economic benefits are reaped in the form of fish, shellfish and other seafood. And by the way, it also explains the highly prized occurrence of oil and gas stocks under present day deltas: these are the fossil remains of the organisms that once thrived in the similarly productive coastal waters.

Table 2.1 Official Ramsar sites in deltas

Delta Site Size

Nile Delta Lake Burullus 46,200 ha

Ganges Sunderbans 601,700 ha

Rhine Delta all open and closed estuaries (10 sites) 188,475 ha

Rhone Delta Camargue & La Petite Camargue 122,000 ha

Ebro Delta entire delta 7,736 ha

Danube Delta entire delta 647,000 ha

Volga Delta entire delta 800,000 ha

Senegal Delta Parc National du Diawling 15,600 ha

Red River Delta Xuan Thuy Natural Wetland Reserve 12,000 ha

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It is not surprising that these rich deltas attract migrating birds. Lying at strategic positions along flyways, delta nature sites are key stepping stones of millions of birds en route from north to south and vice versa. At this moment some 2,4 million hectares of delta wetlands have been given the official status of Ramsar Site, indicating that these wetlands are of international importance for the survival of many bird populations (see Table 2.1). In three instances, even the entire delta has been designated as official Ramsar site, viz. the Ebro, Danube and Volga delta.

Functions and values for mankindDeltas are a gift of nature to mankind. Deltas have flat, highly fertile soils that are easy to till. They can be travelled across on its waters, full of fish. But as the

Table 2.2: major ecosystem functions in deltas

Category Function Ecosystems and mechanisms (main examples)

Regulation functions Storm and flood protection

Mangroves, coral reefs, salt marshes, dunes, etc.

CO2 sequestration Forests

Nutrient cycling Estuarine denitrification

Soil formation delta development (sediment deposition etc.)

Habitat functions Refugium function Suitable living space for wild plants and animals

Nursery function Suitable reproduction habitat (e.g. mangroves as nursery for fish&shrimp)

Production functions Food production Fishery & agriculture

Raw materials Sand and clay / wood

Energy production Tidal energyWind energy

Information functions Recreation & tourism Beach recreationWatersportsEco-tourism

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sea gives, it can also take. Their low lying topography make deltas vulnerable to storm surges and river floodings. And if not from aside, the seawater enters from below: seepage of saline groundwater poses a constant threat to the crops. Hence, man has to dig and develop. Land reclamation, irrigation, soil drainage and embankments have made many a delta hospitable: a place to safely live in and to live off the fruits of the land and sea. Several of the deltas have developed into the major granary or rice bowls of an entire country, such as the Red River Delta in Vietnam and the Godavari and Krishna deltas in India.

A generic classification of functions and values of nature and natural processes is given by (de Groot et al., 2002) and distinguishes regulation-, habitat-, production- and information functions. Nature provides these functions, free of cost, to mankind. In deltas, ecosystems provide the following major functions (Table 2.2):

Table 2.2 shows that for instance ‘Storm and flood protection’ is provided by delta ecosystems that include mangroves, coral reefs, dune systems and salt marshes, but can also include coastal forests, seagrass beds, intertidal flats, and lagoons, depending on the delta in question. Mechanisms for regulating storm and flood impacts in coastal areas include: wave dissipation, barrier to flood surge, wind breaking, coastal accretion and stabilization (long-term) and regulation of sediment transport linked with coastal geomorphology. Obviously, coastal ecosystems can perform several of these functions simultaneously: a mangrove forest protects land from a storm surge, it provides a nursery area for fish and shrimp, it yields useful timber and serves as a habitat for many species including migrating birds. Section 2.5 presents several examples of multifunctional uses.

How much are these functions worth? One well known study has estimated the monetary value of the world ecosystems. In this study, (Costanza et al., 1997) calculated that estuaries have the highest economic value of 22,832 US $ ha-1 year-1 of all ecosystems. Nutrient recycling and food production are the major functions that contribute to their high economic value. Off shore seagrass and algae beds closely follow with 19,004 US $ and tidal marsh/mangroves contribute a respectable 9,990 US $. These figures become all the more significant when compared with, for instance, tropical forests (2007 US $) and open oceans (252 US $). These figures signify the enormous relative importance coastal and delta ecosystems have for humankind.

‘Estuaries have the

highest economic

value of all

ecosystems’

‘Estuaries have the

highest economic

value of all

ecosystems’

26

Status and trends in delta values and functionsThe most important direct drivers of change in ecosystems worldwide – and probably also for delta ecosystems – are habitat change, overexploitation, invasive alien species, pollution and climate change. Habitats are converted to agricultural land or shrimp ponds and especially fish stocks are overexploited. Alien species and disease organisms continue to increase because of both deliberate introductions and accidental translocations through commercial shipping related to growing trade and travel, with significant harmful consequences to native species and many ecosystem services. With respect to pollution, particularly the nutrient loading to regional seas is disturbing: Excessive flows of nitrogen contribute to eutrophication of freshwater and coastal marine ecosystems. For instance, there has been an 10 fold increase in nitrogen flux of the Yellow river to the sea since the industrial and agricultural revolutions and for the North Sea watersheds this is even a 15-fold increase.

Table 2.3 Drivers of coastal change (source: (Agardy & Alder, 2005)

Habitat Loss or Conversion Habitat Degradation Overexploitation

Coastal development (ports, urbanization, tourism-related development, industrial sites)

Destructive fisheries (dynamite, cyanide, bottom trawling)

Coastal deforestation (especially mangrove deforestation)

Mining (coral, sand, minerals, dredging)

Civil engineering works

Environmental change brought about by war and conflict

Aquaculture-related habitat conversion

Eutrophication from land-based sources (agricultural waste, sewage, fertilizers)

Pollution: toxics and pathogens from land based sources

Pollution: dumping and dredge spoils

Pollution: shipping-related

Salinization of estuaries due to decreased freshwater inflow

Alien species invasions

Climate change and sea level rise

Directed take of low-value species at high volumes exceeding sustainable levels

Directed take for luxury markets (high value, low volume) exceeding sustainable levels

Incidental take or bycatch

Directed take at commercial scales decreasing availability of resources for subsistence and artisanal use

2�


Indeed, compared to other types (such as forests, drylands and mountains), worldwide coastal ecosystems have been most impacted over the last century by all of these drivers and current trends are increasing (MEA, 2005). In Table 2.3 a description of the major drivers of change on the delta ecosystems have been indicated.

Loss of habitat can occur through a variety of causes, but the majority of habitat loss in delta environments is the conversion of freshwater- and salt marshes into agricultural land (for instance through land reclamation) and – in the tropics – the conversion of mangroves into aquaculture. Worldwide decline in mangrove forest is estimated to be around 2% per year between 1980 and 1990 and 1% per year between 1990 and 2000 (Lewis III, 2005). In the 18th century the Sundarbans of Bangladesh (the largest single mangrove forest in the world) was twice its present size, which was lost to agricultural lands of the adjoining landlords (Chowdhury and Ahmed, 1994).

But also a more complex set of factors can lead to reductions in original delta habitats. For instance, the combination of subsidence, incidental hurricanes and the construction of levees and canals (for the oil exploration and navigation) has led to massive reduction in Louisiana’s coastal wetlands. An area the size of a football field disappears every 35 minutes (National Geographic News, 2005). Louisiana had already lost 1,900 square miles of coastal lands, primarily marshes, from 1932 to 2000. 217 square miles of Louisiana’s coastal lands were transformed to water after Hurricanes Katrina and Rita (USGS, 2006; USGS reports on latest land change estimates for Louisiana coast; USGS News Release, October 3, 2006). Estuarine systems are among the most invaded ecosystems in the world. Often introduced organisms change the structure of coastal habitat by physically displacing native vegetation. For example, San Francisco Bay in California has over 210 invasive species, with one new species established every 14 weeks between 1961 and 1995. Most of these bio-invaders were brought in by ballast water of large ships or occur as a result of fishing activities. (Agardy & Alder, 2005)

Of all potential impacts of a rising global temperature, sea level rise is probably the most important for deltas. Combined with subsidence of the delta soils, sea level rise can lead to a series of changes in the delta environment. It increases coastal erosion, thereby threatening human settlements and enlarging the

‘sea level rise is

probably the most

important climate

change induced

factor for deltas’

‘sea level rise is

probably the most

important climate

change induced

factor for deltas’

2�

risk of coastal flooding. But sea level rise also leads to landward movement of the tidal influence and salt wedge in rivers, which jeopardizes freshwater intakes for agricultural, industrial and domestic water supply systems.

That coastal erosion can also occur without a change of climate, is a well known fact. It has everything to do with the sediment balance within a coastal cell, which can be disrupted by natural and human-induced causes. A good example of the latter is the increased erosion along the Nile Delta after the completion of the Aswan High Dam (see Figure 2.1).

Compared with the past five decades, both river discharge and sediment load will probably decrease for some large river systems with 30-40% in the next 50 years and decrease up to 50% in the next 100 years as a result of

Figure 2.1: Coastal erosion Nile Delta: coastline changes in Egypt between 1935 and 1985

(from West Damietta to West Port Said)

2�


human activities and dam construction. Thus general erosion in the coastal zone, including estuaries, deltas and associated beach systems seems to be inevitable (Agardy & Alder, 2005).

What can we do about it? The good news is that delta ecosystems can be relatively easily restored. Because the delta environment is highly dynamic, delta nature has a remarkable adaptive and resilient capacity. In contrast to for instance tropical rainforests which require centuries to reach a climax succession stage, delta ecosystems such as salt marshes, mangroves and dunes develop quickly into rich habitats once the environmental conditions are favourable.

All over the world we see restoration ideas turning into reality. Of course not every initiative is an immediate success. There is much trial and error. But the most important thing is that people see the need to protect their environment and to work with nature instead of against it. In this chapter a number of these initiatives will be presented, some of them still in its early conceptual stage, but others already worked out in practice. These best practices show the importance of:• Good knowledge of the basic physical and ecological processes;• Early involvement of local stakeholders leading to a participatory planning

process;• An integrated approach

We have selected experiences that illustrate different ways of combining ecosystem functions for the benefit of society. In the next section we will show how nature can help in protecting the coast, by soft and ecological engineering. Then we present examples that demonstrate the benefit of safeguarding the integrity of coastal ecosystems by restoring estuarine dynamics and guaranteeing a minimum river flow. We proceed by presenting a showcase in the ‘Room for Rivers’ philosophy and we conclude with examples of the multiple use of wetlands.

‘the good news

is that delta

ecosystems can be

relatively easily

restored’

‘the good news

is that delta

ecosystems can be

relatively easily

restored’

30

2.2 Natural coastal protection and wetland restoration

There is ample evidence that coastal protection can greatly benefit from a resilience based approach. Many of the world’s coastlines are highly dynamic by nature through the forces of winds, waves and currents. Hard engineering structures have more often than not led to increased erosion, either on the location itself, or at nearby, unprotected beaches. Instead, coastal practitioners are increasingly applying soft engineering measures, such as beach and foreshore sand nourishments. Modern modelling and surveying techniques are used to optimise these nourishments, whereby the question is how to best make use of the prevailing local physical conditions. A new approach of ‘super-nourishments’ is currently being under study in the Netherlands (see Box 2.1).

Box 2.1

Rhine case: sand nourishment through pilot of Sand engine, suppletion strategy from new Delta committee

Sand nourishment is the mechanical placement of sand in the nearshore zone to advance the shoreline or to maintain the volume of sand in the littoral system. It is a soft protective and remedial measure that leaves the coast in a more natural state than hard structures and preserves its recreational value. The method is relatively cheap if the borrow area is not too far away (<10 km) and the sediment is placed at the seaward flank of the outer bar where the navigational depth is sufficient for hopper dredgers. Three types of nourishments are distinguished: beach-, shoreface- and dune nourishments (Van Rijn, 2008).

It should be noted that these kinds of measures need to be repeated every few years, because due to wave and current forces, these nourishments will be gradually spread out to the onshore and offshore direction. Typical lifetime of a normal shoreface nourishment is in the order of 5 years (Van Rijn, 2005). Therefore, also other alternative techniques of nourishments are being studied.

At this moment the potentials and risks of a ‘super-nourishment’ called ‘The Sand Engine’ in front of the Dutch coast (shoreface) are being investigated. Although the current beach nourishments are successful and effective for local coastline maintenance, such a super-nourishment could turn out to be more efficient in serving more functions than safety alone. The idea is to apply an extra amount of sand that would be redistributed by nature itself, thus stimulating natural dynamics of the coast, increasing a bufferzone for future sea level rise and enlarging the coastal intertidal zone which is beneficial for natural and recreational values alike.

31


Besides and in addition to these sand nourishments, also ecological engineering is being practiced. From the notion that mangroves can provide effective storm protection (see Box 2.2), there is increased attention to restore these coastal forests. Great potential exist to reverse the loss of mangrove forests worldwide through the application of basic principles of ecological restoration using ecological engineering approaches. Mangrove restoration can be successful, provided that the hydrological requirements be taken into account, which means that the best results are often gained at locations where mangroves previously existed, such as abandoned) aquaculture ponds (Lewis III, 2005; Stevenson et al., 1999; Samson & Rollon, 2008).

Ecological

engineering

approaches offer

great potential

Ecological

engineering

approaches offer

great potential

Figure 2.2: Mangrove seedlings waiting for transplantation (Banda Aceh, Indonesia)

32

Box 2.2

Example of storm protection by mangroves

Since 1822, a total of 69 extreme cyclones landed on the Bangladesh coast of which 10 hit the Sundarbans mangrove forest. However, a cyclone that lands on the Sundarbans causes less damage compared to the likely damage caused the cyclone of equal magnitude lands on the central and eastern part of the coast. Most of the cyclone damage is caused by the surge. For example, a cyclone that landed on the Cox’s Bazar coast generated 4.3 m surge caused deaths of 11,069 people in 1985. On the other hand, when a similar cyclone landed on the Sundarbans in 1988, the number of fatalities was just half of the 1985 cyclone (MEA, 2005).

2.3 Integrity of ecosystems: biodiversity, environmental flows

In our relentless effort to reshape our coastal environment for our own benefit, we sometimes forget that everything has its price. Besides the profits we gain, there are also losses to sustain. But instead of accepting these losses in biodiversity and ecological functions, there are ways to restore the integrity of ecosystems. This does not necessarily require a complete restructuring of the original situation, but can also lead to a rejuvenation or improvement of already modified ecosystems. A good example is the restoration of estuaries by reconnecting them with rivers and sea without compromising the attained high safety against flooding in the Rhine Delta of the Netherlands (Box 2.3).

Ensuring the integrity of the linkages between delta and river often also requires measures upstream. Developments in the river basin, such as deforestation, irrigation and hydro-power generation dams all exert an influence on the well-being of delta ecosystems. Sediment loads change, freshwater inflows often reduce and persistent pollutants accumulate. Recently new insight has been gained with respect to the importance of freshwater inputs in coastal ecosystems. Seasonal changes in river flow can temporarily change the ‘normal’ condition of an estuary. Usually the estuarine ecosystems and their species are adapted to this highly dynamic environment as long as these seasonal variations remain within the average natural dynamics. Upstream water diversions can permanently change this pattern with significant consequences for the estuarine ecosystem. Establishing an environmental

Setting and

maintaining

environmental

flow requirements

promotes the

integrity of

ecosystems

Setting and

maintaining

environmental

flow requirements

promotes the

integrity of

ecosystems

33


flow requirement is being considered as an important management measure to guarantee the integrity of downstream ecosystems. An example of how this is done is presented for the Yellow River Delta (see Box 2.4)

Box 2.3

Restoration of estuarine dynamics in the Rhine Delta, The Netherlands

The Southwestern delta has a long history of embankments. Embankments have a twofold effect. Inside dike rings, active sedimentation is excluded and thus dike rings must be considered to be completely sediment starved. Moreover, soil compaction, peat oxidation and drainage lead to self perpetuating land subsidence. Increasing saline seepage is one of the side effects. Outside the dike ring, in the estuaries, storm flood levels increase due to the decreased basin storage. The cumulative effect of sediment starvation, land subsidence, sediment export and sea level rise is an enormous historical sediment deficit, defined as the negative difference between land surface and Dutch ordnance datum (NAP). The total deficit for the Dutch lowlands is estimated at 13.3 km3 (vd Meulen et al., 2006). The sediment deficit for the delta area is illustrated in figure 2.3, comparing the land surface in the delta anno 1000 and the land surface above sea level in the delta at present.

Figure 2.3: Comparison land surface above sea level delta anno 1000 and 2000

The reshaping of the formerly morphologically dynamic delta into a completely petrified landscape, eliminating adaptiveness and resilience, indeed has its price! And the bad message is that there is no way back. Morphodynamics cannot be reintroduced without jeopardizing safety against flooding. History commits to continued and even increasing dependency on flood defenses.

34

As a consequence of the last great flood in 1953 the Dutch government decided to close off most of the Delta estuaries, turning them into stagnant salt or freshwater lakes. Although safety from flooding was greatly enhanced, it turned out that these new ecosystems did not develop satisfactory. In the closed estuaries, shoreline erosion forms a threat for the remaining terrestrial and transitional zones between the dike and water. In the remaining open estuaries, the Eastern and Western Scheldt, the vulnerability of salt marshes to erosion also increased: in the Eastern Scheldt because of the diminished tidal influence, and in the Western Scheldt because of dredging operations to maintain a deep channel as shipping route to Antwerp.

GREVELINGEN

VEERSE MEER

OOSTERSCHELDE

WESTERSCHELDE

ZOOMMEER

MARKIEZAATSMEER

KRAMMER-VOLKERAK

BRUGGE

ROTTERDAM

BERGEN OP ZOOMMIDDELBURG

VLISSINGEN

ANTWERPEN

HOLLANDSCHDIEP

HARINGVLIET

TERNEUZEN

NIEUWE WATERWEG

Figure 2.4: Summary of measures to restre estuarine dynamics

35


Besides these morphologically induced problems most waters also suffer from an impoverished water quality. Many of the closed-off water bodies, like for instance brackish Lake Veere and saline Lake Grevelingen, experience stratification and anoxia in deeper layers, mainly because of reduced refreshment and long water residence times. The worst situation exists in the freshwater Lake Krammer-Volkerak, where eutrophication processes caused by agricultural run-off lead to a very bad water quality with extensive scums of blue green algae.

Some years ago, the provincial managing authorities have drafted a vision for the future, in which the restoration of estuarine dynamics has a prominent place. Central to this vision is to partially restore the tidal dynamics and/or to restore the link with the rivers, while maintaining the same level of safety. This will start the water flowing again, which improves the natural turnover of nutrients and production of shellfish, fish and birds without the nuisance of algal blooms. Each water body in the Delta requires its own approach. Although the first sluice between Lake Veere and the Eastern Scheldt has opened already back in 2004, it will take many years to complete the implementation of this new vision.

Box 2.4

Yellow River Delta: environmental flow requirements to protect downstream water uses

Fresh water is of key importance for many economic activities in the Yellow River Delta. It is used as drinking water, for growing crops, for industrial activities and for maintaining healthy ecosystems. Of all consumers, the irrigated agriculture has the highest demand, which is not surprising because of the high evaporation rate during most of the year. This evaporation surplus causes capillary rise of the saline groundwater into the top soils, which has to be flushed with fresh water. Currently around two third of the Delta area has moderate to serious salinity problems.

The most important source of freshwater is the Yellow River. But unfortunately, the Yellow River basin is very deficient in water resources. The conflict between supply and demand is prominent. Especially since 1992 annual discharges of the lower Yellow River reached dangerously low levels, leading to frequent periods of zero discharges of more than 100 days per year. From 1995 to 1998, the river was dry during more than 120 days every year, up to as much as 226 days at Lijin in 1997. This regular drying up of the lower Yellow River had serious impacts on the downstream socio-economic functions and caused large ecological damages in the delta. Therefore, the Yellow River Conservation Commission (the basin wide administrative agency) has implemented a regulated discharge regime of the river since 1999, in order to recover the river stretches downstream of Lijin (Liu Xiaoyan et al., 2006). This relieved the risk of drying up and the water deficiency in the lower delta to some extent.

36

However, there is still a long way to go to the optimal allocation of water resources required by all economic sectors and the ecosystems of the delta (Liu Gaohuan & Drost, 1997; Liu Gaohuan, 2006).

Until recently, for the Yellow River, little was known about the exact water demand for ecological system development of the delta and about the ecological effect and influences of allocation of water. Especially, proper identification of the habitats demanding water in the delta was lacking, as well as the amount of water needed to restore damaged wetland ecosystems and to maintain sustainability of the delta ecology (see e.g. Guan Yuanxiu & Liu Gaohuan, 2003). A recent study on the water allocation for the two Nature Reserves in the lower Yellow River Delta revealed that the total future water requirement that includes domestic, industrial, agricultural and restored wetland demands is less than 10% of the annual average river discharge at Lijin. Although this suggests that there is ample water, the situation could be different in the months of March, April and May. During this low flow period the water demand is typically at its highest and critical situations (e.g. in dry years) are not ruled out. This exemplifies the need for an optimization of water requirements through daily water management (Lian Yu et al., 2007).

2.4 Room for rivers

For centuries rivers have been harnessed to make better use of them. Normalisation and canalisation have straightened and narrowed naturally meandering and braided river systems into a single channel system, benefiting navigation for increasingly bigger ships. Embankments were raised to reduce flooding frequencies of the adjacent lands, which became more and more populated. Over the past decades the adverse consequences of these river engineering measures became apparent. Natural values have greatly declined and river beds eroded, leading to undermining of sluices and bridges. Groynes and the narrowing of the floodplain impeded a rapid discharge of water and ice, increasing the risk of flooding. As climate change could result in higher peak discharges, river managers were confronted with the question to further heighten the sea defenses or exploring other possibilities. The ‘Room for Rivers’ concept, giving back the areas of natural horizontal expansion during floods through wideing of floodplains and creation of retention areas, was born out of a belief that it is better to opt for a more resilient strategy than to go for resistance against the forces of nature. The Rhine programme in the Netherlands is a showcase for this new philosophy and supports the paradigm shift from ‘fighting the floods’ to ‘living with water’.

‘Room for rivers’:

a more resilient

strategy for flood

risk management

‘Room for rivers’:

a more resilient

strategy for flood

risk management

3�


Box 2.5

Rhine programme ‘Room for Rivers’

High discharges of the Rhine and Meuse Rivers in 1994 and 1995 have led to a significant shift in dealing with safety against river floods in the Netherlands. The age old practice of raising and strengthening of embankments along the rivers is replaced with a new approach, giving more room to high waters. This so-called room for rivers policy contains a wide range of measures, such as lowering of floodplains, creation of side channels, lowering of groynes, river dredging and realignment of dikes. Dike strengthening has become a last option, if other interventions prove to be technically or financially impossible. Most of these measures will have significant consequences on regional and local spatial planning. This makes public participation in planning of flood management strategies crucially important. It also calls for a more integrated planning, thereby combining safety objectives with other policy goals, such as nature development, landscape quality improvement and economic prosperity. The new management policy is now being implemented over the entire stretches of the Dutch parts of Rhine and Meuse in a multi-billion Euro programme. Besides practical innovations in river management, the programme is also innovative with respect to its planning approach of ‘central direction and decentralised implementation’. This creates opportunities for innovative public private partnerships, such as Design & Construct agreements, in which planning and implementation is dealt with through one contractor. This requires great adaptation skills from both contractor and government agencies, and a path of trial and learning. The programme has to be finished in 2015.

Figure 2.5: River improvement measures in Room for Rivers concept

3�

2.5 Multiple use of wetlandsAs coastal wetlands can perform different functions, this means that they do not necessarily need to be protected by denying access. Local people often have used these ecosystems for centuries and are eager to continue doing so. But how can this use be allowed without compromising the integrity of wetlands, without leading to overexploitation of the natural resource? This problem can be tackled by using the ‘ecosystem approach’. This approach is advocated by the Convention on Biological Diversity and denotes a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way. It is based on the application of appropriate scientific methodologies focused on levels of biological organization which encompass the essential processes, functions and interactions among organisms and their environment. It recognizes that humans, with their cultural diversity, are an integral component of ecosystems (website Convention on Biological Diversity).

Below three examples are given of multiple use of wetlands. Box 2.6 illustrates the values of Xuan Thuy Ramsar reserve in the Red River Delta, Vietnam. Because of weak management these values are presently under great pressure. The second example (Box 2.7) is considered as a world-renowned model for multiple use of wetlands: the East Calcutta Wetlands. And the last example (Box 2.8) is the restoration of infertile, acid sulphate soils (a widespread problem in several tropical deltas and coasts) by the replanting of the original vegetation, such as the Melaleuca trees in the Mekong delta.

Box 2.6

Example of a multifunctional value Ramsar site

Xuan Thuy Natural Wetland Reserve. 20/09/88; Nam Ha; 12,000 ha; 20º10’N 106º20’E. Strict Nature Reserve. Delta and estuary islands supporting the last significant remnants of coastal mangrove and mudflat ecosystems in the Red River Delta; includes land enclosed by sea dikes, with fringing marshes. A critically important area for migratory waterbirds and shorebirds, regularly supporting several globally threatened species. Human uses include fishing and aquaculture yielding up to 10,300 tonnes per year, rice production yielding 40,000 tonnes per year, duck rearing, bird hunting, and reed harvesting. The mangrove forest is of considerable importance in maintaining the fishery, as a source of timber and fuelwood, and in protecting coastal settlements from the full impact of typhoons. Ramsar site no. 409. Most recent RIS information: 1992.

Ecosystem

approach for a wise

multiple use of

wetlands

Ecosystem

approach for a wise

multiple use of

wetlands

3�


Box 2.7

Example of a multiple use wetland: East Calcutta Wetlands. West Bengal (12,500 ha).

World-renowned as a model of a multiple use wetland, the site’s resource recovery systems, developed by local people through the ages, have saved the city of Calcutta from the costs of constructing and maintaining waste water treatment plants. The wetland forms an urban facility for treating the city’s waste water and utilizing the treated water for pisciculture and agriculture, through the recovery of nutrients in an efficient manner - the water flows through fish ponds covering about 4,000 ha, and the ponds act as solar reactors and complete most of their bio-chemical reactions with the help of solar energy. Thus the system is described as “one of the rare examples of environmental protection and development management where a complex ecological process has been adopted by the local farmers for mastering the resource recovery activities” (RIS). The wetland provides about 150 tons of fresh vegetables daily, as well as some 10,500 tons of table fish per year, the latter providing livelihoods for about 50,000 people directly and as many again indirectly. The fish ponds are mostly operated by worker cooperatives, in some cases in legal associations and in others in cooperative groups whose tenurial rights are under legal challenge. A potential threat is seen in recent unauthorized use of the waste water outfall channels by industries which add metals to the canal sludge and threaten the edible quality of the fish and vegetables. Ramsar site no. 1208. Most recent RIS information: 2002.

Box 2.8

Melaleuca wetlands for provision of ecosystem services in the Mekong delta

Currently about half of the Mekong Delta has acid sulphate soils, as a result of drainage of wetlands and the expansion of aquaculture and canals. This severely limits the agricultural potential of the delta. Recent research on ecosystem functioning has helped build understanding of how environmental and economic benefits can be simultaneously achieved. In particular, research has demonstrated the role of Melaleuca trees (Melaleuca cajuputi) in improving water quality, thereby lowering the acidity of soil in surrounding fields. The relationship between depth of water in the Melaleuca wetland forest reservoir and days of irrigation needed for good soil quality has been established. This discovery makes it possible to use Melaleuca to lessen the acidity of affected soils and increase agricultural production.

40

3.1 Role of infrastructure in delta development

Living in deltas has always required human intervention. Infrastructure was developed to adapt the natural systems to create more favourable conditions for living and working in deltas. Traditionally the development and maintenance of infrastructure has been the task or responsibility of governments. A responsibility which is more and more shared with other parties through public-private partnership.

3. Extension and revitalization of infrastructure

41

Extension and revitalization of infrastructure

Demographic and economic development lead to a growth in the number of people and economic activities to be served and protected. As a consequence demands on the infrastructure will grow. There are also trends in society and governance to reckon with in the development of infrastructure, such as environmental; concerns, privatization and decentralization. At the same time, the vulnerability of deltas is increasing because of rising sea levels, subsiding soft soils, and increasing pressure on space and environment. Dealing with all these developments together is a complex and challenging task. There are basically two options to respond to the increase in vulnerability: (i) adapting land and water use or (ii) adapting the infrastructure.

Box 3.1

Development of infrastructure in The Netherlands: a short history

The Dutch history of human intervention in deltas is a history of land reclamation and flood protection. Huge areas of land were already reclaimed in the 17th and the 18th centuries, thanks to technological and economic developments. At the end of this period, large water bodies had been transformed into productive agricultural land, partly by reclaiming broad meres and lakes, partly by reclaiming silted up land outside the dikes. Improvements in drainage techniques enhanced the quality of the reclaimed ‘polder’ land (a polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity).

The process of land reclamation was continued in the 19th and 20th century on an even larger scale. The largest lake reclamation scheme of the 19th century was that of the Haarlemmermeer (nowadays host to Schiphol international airport) in 1852, with a size of well over 18,000 hectares. Land reclamation in the 20th century was concentrated in the Lake IJssel area (with four polders with sizes of 20,000, 43,000, 48,000 and 54,000 hectares) . This lake was formed in the 1930’s after the construction of the Closure dam (Afsluitdijk). The dam was build in response to a major flood in 1916 in the area of the former Zuiderzee.

Another serious storm surge in 1953 triggered the construction of the Delta works. The project included the closure of all sea inlets, except for the Rotterdam Waterway (entrance to the Port of Rotterdam) and the Western Scheldt (entrance to the Port of Antwerp). The Delta works together considerably shortened the total length of the coastline and thus the length of the potentially vulnerable coastal defenses. The plan for closure of the Eastern Scheldt, the largest sea inlet of all, was finally abandoned. In stead, after a societal debate, a storm surge barrier was build to maintain the Eastern Scheldt’s abundant marine flora and fauna, its rich tidal salt marshes and shellfish fisheries. The debate on the Eastern Scheldt was a landmark in the Dutch history of delta development. For the first time the need for safety against flooding was reconciled with environmental concerns.

42

This chapter will focus on extension and revitalization of infrastructure. It will discuss how infrastructure is being developed to enable delta life. It will be discussed how development of infrastructure may help to deal with the ever increasing pressure on available space in deltas and how it may help to secure future water supplies. Other important drivers for the development of infrastructure are the sea-ward extension of ports and the growing interest for the generation of renewable (hydro) energy.

Environmental concerns play an important role in the design and construction of infrastructure. In fact these concerns have given rise to a shift in paradigm from building against nature to ‘Building with Nature’. There is also a trend towards more robust infrastructure in response to a growing risk aversion in societies. Another observation is that a lot of infrastructure in deltas is already present for decades or centuries. Rehabilitation of this infrastructure will be a tall order for the (near) future. Technological development may open new opportunities to enhance the functionality of infrastructural solutions. Technological development may also help to extend the life time of infrastructure and/or to develop more cost-effective designs and construction methods of infrastructure. The perspectives of technological development are discussed at the end of this chapter.

3.2 Infrastructure to support economic development

Dealing with pressure on available space Population growth and economic development lead to an ever increasing pressure on the available space in deltas. Basically there are two options to deal with this pressure: enlarge the available space or combine different functions of the available space. The first option: land reclamation was and is a proven way to deal with this pressure: However, the increasing pressure on the available space also drives a growing interest in the second option: the multifunctional use of infrastructure.

Land reclamationThe Netherlands has a century old tradition in land reclamation. Several 1000 km2 of land have been reclaimed from the 17th till the middle of the 20th century. The final polder that was reclaimed was Zuidelijk Flevoland in 1968 in the Lake IJssel area. The plans to reclaim one more polder in the Lake IJssel area (the so-called Markerwaard) were abandoned because of budgetary and

43


environmental reasons. Although the actual land reclamation came to a halt, the concept of land reclamation kept its attraction. In the last few decades various plans for land reclamation were developed, including an extension of the coast in between Hoek van Holland and The Hague (Plan Waterman) and an island in the North Sea to host a new airport, etc. None of these ideas, however, have yet been implemented. Most recently the new Delta Committee proposed a seaward extension of the coastline with about 1 km to promote coastal development more or less as a ‘by-product’ of improving the protection against coastal flooding.

While land reclamation ideas in the Netherlands did not go beyond the drawing-board, land reclamation worldwide was a thriving business. The last decade shows a number of prestigious land reclamation projects being completed. These include the airport development in Hong Kong and the island resorts developments along the coast of Dubai.

Land reclamation has grown into a popular strategy in cases where the pressure on the available space is high. The land reclamation examples of Hong Kong and Dubai are large scale and technologically advanced. Their implementation required large investments too. There are, however, also other ways of reclaiming land. In the delta of the Ganges / Brahmaputra in Bangladesh natural processes of river morphology are used to reclaim land on a local scale. The high dynamics of the rivers support a relatively cheap way of land reclamation. It compensates, however, only partly of the loss of land due to erosion.

Multifunctional use of infrastructure.A promising way to respond to the increasing pressure on space is through multifunctional use of infrastructure. Revitalization of infrastructure opens new opportunities for multifunctional use. Examples to be discussed later in this chapter include the transition of conventional embankments into super levees in Japan and the rehabilitation of the Closure dam of Lake in The Netherlands.

Multifunctional use of infrastructure may be especially promising for flood protection works. Linking flood protection to other development issues such as urban (re)development or nature development may be an attractive way to combine more immediate benefits of e.g. urban development with the long term benefits of flood protection. As such it may contribute to secure the necessary funds for improvement or maintenance of flood protection works.

Land reclamation

is a well-proven

way to deal with

increasing pressure

on space

Land reclamation

is a well-proven

way to deal with

increasing pressure

on space

Revitalization of

infrastructure

opens opportunities

for multifunctional

use

Revitalization of

infrastructure

opens opportunities

for multifunctional

use

44

Securing future water suppliesDue to climate change prolonged and more frequent periods of drought are expected. At the same time water demands in deltas are increasing because of population growth and economic development. As a consequence water shortages will grow in magnitude and frequency, unless land and water use will be adapted or future water supplies will be improved either by storage or transfer.

In many countries shortage of fresh water is viewed as one of the most serious challenges in water resources management. Even in a country such as the Netherlands, with generally an abundance of water, droughts occasionally occur. Due to climate change water shortages are expected to become more likely and counter measures are being considered. In fact the Delta committee has proposed to raise the target water level of Lake IJssel with some 1.5 m to increase the amount of water being stored. The water from this lake provides a source of water supply to other parts of the country in periods of drought.

The expected increase in water shortages is a major trigger for adaptation to climate change. However in some countries such as Spain, the drought problems are so acute that emergency measures are taken.

Projects for improving the water supply may offer opportunities to realize other objectives as well. An example of such multipurpose development is the development of Marina Bay in Singapore, addressing flood protection, water supply and recreation.

Box 3.2

Water shortages and adaptation to climate change (example from Spain)

The drought problem in Spain is treated rather separately from the adaptation to climate change, despite the obvious and recognized link between the two. In general, drought is regarded as an emergency issue and many ad-hoc actions are taken. This happens often on a short time scale, which does not necessarily fit with the long-term adaptation to climate change. Many activities aim at solving particular bottlenecks caused by drought, especially in the irrigated agriculture. Examples of such measures are the implementation of interbasin transfers, a much disputed issue in Spain, as well as the continuous inauguration of desalination plants, especially close to the major coastal cities such as Barcelona. These kind of drought-driven activities are sometimes included in plans for adaptation to climate change, but tend to be implemented independent as a kind of ‘no-regret’ measures.

Shortages of fresh

water are a major

concern in delta

development

worldwide

Shortages of fresh

water are a major

concern in delta

development

worldwide45


Sea-ward extension of portsEconomic development implies among others a growth of trade. To accommodate the growing transport of goods, ports are relocated or extended in seaward direction, navigation channels are deepened, etc. Also containerization of transport plays a role in this development (e.g. Rotterdam, Melbourne). The port areas left behind may offer opportunities for urban (re)development with waterfront access.

Box 3.3

Securing future water supplies in Singapore (Marina Reservoir project)

To protect the city center for floods and to meet future demands for drinking water, Singapore has developed the Marina Bay project in the period of 2005 – 2008. A dam has been constructed to create a fresh water reservoir. The dam is equipped with movable gates and a large pumping station for control of the water level in the reservoir. The fresh water reservoir is expected to be fully operational in 2010 after a transition period in which additional measures (such as a sewer rehabilitation program, a recirculation scheme and implementation of aerators) will be implemented. An issue of concern is the future water quality. For instance eutrophication of the reservoir may become a serious problem, unless the inflow of nutrients can be reduced considerably.

The construction of the Marina reservoir is a typical example of a multipurpose development. Apart from better protection against floods for low-lying parts of Singapore it provides a major contribution to securing future water supplies and new opportunities for water-based recreation.

Box 3.4

Maasvlakte-2 land reclamation for Port of Rotterdam

Directly to the west of the current port and industrial area of Rotterdam, a new location for port activities and industry is being created in the North Sea: Maasvlakte 2. The land reclamation will measure around 2000 hectares in total. Half of this will consist of infrastructure, such as sea defenses, fairways, railways, roads and port basins. The other 1000 hectares will provide the space for industrial sites. Some of he port areas left behind near the city of Rotterdam will be redeveloped for housing as well as office buildings.

46

Port developments are often objected because of environmental impacts. The example of the development of the Maasvlakte-2 extension for the port of Rotterdam shows that compensation for such impacts through nature development outside the project area may contribute to the actual realization of plans.

New impulses for hydro-energy?Economic development, unless serious energy saving programs are implemented, may imply a growth in energy consumption. In line with mitigation policies for climate change there is a growing interest in the potential of deltas for renewable energy. Specifically in deltas there are a number of ways in which water may serve as a source of sustainable energy, waiting to be tapped. These include energy from tides, from waves and from salinity gradients.

The opportunities of water for energy generation have been explored in an innovation program in The Netherlands. The study looked into the potential of the various sources, and the perspectives for actual generation from both a technical and societal point of view. The perspectives of energy generation from tides and waves in the Netherlands were found to be rather limited. Most potential is in the generation of energy from fresh-salt gradients using Pressure Retarded Osmosis (PRO) and/or Reversed Electrodialysis (RED). The Closure dam which separates the fresh water of Lake IJssel with the Wadden Sea might be a suitable location for application of this technology. Its application may become part of the required rehabilitation of the Closure dam and would comprise a good example of multifunctional use of infrastructure as well.

To be feasible, energy generation from tides require a sufficiently large tidal difference as well as opportunities to develop a basin. These requirements are hard to meet in The Netherlands. Other countries, however, my offer better perspectives. For example in the UK a barrage In the Severn Estuary is now under serious consideration. This project has been on the drawing board for over 150 years, albeit for different reasons in the past. The Severn Barrage if built, would be the biggest renewable energy project undertaken.

Mitigation policies

for climate change

trigger renewed

interest in hydro-

energy

Mitigation policies

for climate change

trigger renewed

interest in hydro-

energy

4�


Box 3.5

Severn barrage for generation of renewable energy?

In the Severn Estuary there is a major project of international interest being considered at present, namely the Severn Barrage. The Severn Barrage, if built, would be the biggest civil engineering projects since the Channel Tunnel. The project will cost US $30 billion (minimum) and would provide nearly 5% of the UK’s renewable energy. It is one of the most controversial projects of recent times. If operated as proposed it would lead to the loss of 14,000 ha of intertidal habitats. However, it would also lead to reduced flood risk, reduced currents in an estuary (delta) with the second highest tidal range in the world, reduced turbidity and suspended sediment levels, increased light penetration and a higher level of benthic productivity and a change in the flora and fauna.

3.3 Rehabilitation of infrastructure

Due to climate change the physical conditions for which the infrastructure has been designed will become more severe. Larger droughts to overcome, higher water levels to counter and larger loads to withstand. Climate change, without adaptation or counter measures, will result in damage or a loss of functionality of the existing infrastructure. The adequacy of the infrastructure may be further challenged by physical / mechanical ageing of the infrastructure. Also inadequate maintenance may play a role. Some infrastructure is already present for decades or centuries and is in (urgent) need of replacement or rehabilitation. Such rehabilitation will require large investments in the near future. Hence it is important to anticipate on such expenditure.

In many deltas operation and maintenance of infrastructure is an issue of major concern. Active participation of the beneficiaries of the infrastructure is an important step towards a more sustainable development and management of infrastructure. Box 3.6 presents an example from Bangladesh where programmes are being carried out for an improved and sustainable operation and maintenance of infrastructure through stakeholder participation.

Rehabilitation

of infrastructure

will require large

investments in the

near future

Rehabilitation

of infrastructure

will require large

investments in the

near future

4�

Box 3.6

Rehabilitation of water resources infrastructure in Bangladesh

Numerous infrastructure development project for water resources management have been implemented by the Bangladesh Water Development Board (BWDB) with various levels of success. Based on these experiences the BWDB realized that stakeholder participation, local level water management and multi-disciplinary approaches to project planning are essential for an improved and sustainable operation and maintenance of infrastructure. That is why the Integrated Planning for Sustainable Water Management Programme was conceived.

One major objective of the programme is to transfer the management responsibilities (fully or partially) from the BWDB to the people of the community, through democratically established Water Management Organizations (WMO’s). Special features of the Programme include:• Ensuring people’s participation in all stages of the project to create feelings of ownership.• Formation of WMO’s at various levels to ensure participation from among beneficiary groups and

thereby sustainability.• Carry out the rehabilitation and improvement of physical infrastructure to a high standard of

design and construction.• Transferring Operation & Management responsibilities to WMO’s to share responsibilities for

systems and structures

Rehabilitation of infrastructure may create opportunities to invest in new developments and new functionality, including multifunctional use of the infrastructure. An example may be found in The Netherlands: some 75 years after its construction the Closure Dam of Lake IJssel needs rehabilitation. In co-operation with the private sector some eight integrated visions have been developed for the future of the Closure Dam. Apart from a strengthening of the flood defense function, these visions include innovations with respect to nature development and energy generation.

4�


3.4 New approaches in design of infrastructure

From building against nature to ‘Building with Nature’Environmental considerations play a major role in the sustainable development of deltas. Concerns on environmental degradation have been institutionalized into environmental regulation. Almost no infrastructural development takes place without a proper environmental impact assessment. It is, however, not always easy to specify the environmental requirements to be met. These requirements are often subject of debate, and are sometimes hard, if not impossible to meet. That is why a different approach is being advocated. Not to try to minimize the negative environmental impacts, but in stead to make better use of the forces, interactions and materials present in nature. This approach reflects a shift in paradigm from building against nature to ‘Building with Nature’.

The emphasis of the concept of Building with Nature is on sustainable development in densely populated coastal and delta areas. In implementing the method a new flexible dynamic equilibrium coastline is created using sand from the sea. The coastline may consist of a new primary range of dunes with a new beach in front. Solid sea-wall elements such as dams and dikes are kept to a minimum. The emphasis is on flexible soft structures in harmony with the sea, such as dunes and beaches. In the new coastline accretion and erosion are more or less balancing each other, only needing a limited maintenance through periodic beach nourishment.

Building with

nature aims to

make better use of

the processes and

materials present in

nature

Building with

nature aims to

make better use of

the processes and

materials present in

nature

Table 3.1 Breakthroughs needed in ecodynamic development

Natural system knowledge: Design approach: Governance structure:

• static approach ➞ dynamic behaviour

• descriptive ➞ predictive • species ➞ ecosystem

dynamics • false certainty ➞ living with

uncertainties

• engineering-centered ➞ integral thinking

• mitigating adverse environmental effects ➞ adaptation to the natural system

• construction ➞ life cycle management

• reactive ➞ pro-active

• full control ➞ process management

• threats ➞ opportunities • letter of the law ➞ spirit of

the law • closed government-

dominated decision making ➞ open multi-actor processes

50

The flexible integration of land-in-water and of water-in-land, in harmony with the natural environment, offers inherent flexibility and adaptability. Building with Nature has shown to be an environmentally friendly and economically advantageous concept. The concept is applicable in many settings and supports long-term sustainable solutions for the restoration of coastlines and habitats and in new approaches for land reclamation. The concept of is gaining acceptance worldwide.

Recently the concept of Building with Nature is getting new impulses through a large innovation program in The Netherlands. Ecodynamic development, as it is called in this program, starts from the dynamics of the natural system. It is a matter of planning, designing and building with nature. Ecodynamic development utilizes nature as a ‘dynamic engine’ and enhances ecological opportunities. To arrive at a well-established concept for design and development a number of breakthroughs are still required. These include breakthroughs with respect to the knowledge of natural systems, the design approach and the governance structure. These breakthroughs are listed in Table 3.1.

Box 3.7

Dutch Innovation Program ‘Building with Nature’

The innovation program ‘Building with Nature’ focuses on themes such as: • Integrated development planning (improved safety, living conditions and prosperity);• Development and recovery of the natural dynamics of ecosystems;• Protection against flooding from rivers and the sea;• Climate adaptation.

Design challenges that the innovation program will be working on: • Sand nourishment; Mega-replenishments may provide an innovative approach to traditional beach

nourishments, by allowing natural wave and tidal motion to spread the sand to where it is needed along the coast. This will create safe, natural and sustainable coastlines.

• Intelligent redevelopment of the Southwest Delta from predominantly agriculture to combined aquaculture, agriculture, wilderness and coastal protection according to the latest methods, offers prospects of solving spatial planning and environmental issues in deltaic areas around the world.

• Natural coast and shore defenses will be preserved and reinforced in a sustainable low-maintenance way by making use of natural systems (for example mangroves). Spin-offs will include strengthening the natural system, local economic development, and enrichment of fish stocks.

51


Towards more robust infrastructureThere is a trend in how societies deal with risks, including those from natural hazards. Many societies show a growing aversion of risk. Although zero risk is impossible many countries are adopting strategies which aim at a (further) reduction of the probability of failure as well as the impacts of failures. For example the Delta Committee in The Netherlands recently recommended to raise the level of safety with a factor 10. An increase in safely level to respond to the increase in the number of people and assets to be protected.

The trend of risk aversion, together with the expected impacts of climate change, has triggered a demand for more robust flood defense works. The super levees in Japan are a good example of such more robust works.

More robust

infrastructure is

being developed

in response to

a growing risk

aversion

More robust

infrastructure is

being developed

in response to

a growing risk

aversion

Mekong Delta

52

Box 3.8

Super levees: Japan’s response to increasing flood risks

To respond to increasing flood risks with its devastating consequences to society, Japan had developed the concept of super levees. A super levee is a river embankment with a broad width which can withstand overflow. It prevents uncontrolled flooding due to a dike break. The slope of the embankment is made very gentle. In the unlikely event that the river rises above the embankment, the water would spill ‘gently’ down the slope. The embankment is protected from destruction and serious damage to assets along the river is minimized. The super levee differs from the conventional embankment, which is basically a wall separating the hinterland from the river.

The adaptation of conventional dikes to super levees offers a number of benefits. A super levee is better resistant to overflow, seepage and earthquakes. In addition it provides usable land and space for urban developments and it restores access to the riverfront. The concept of super levees is also a good example of multifunctional use of infrastructure.

53


Similar to the concept of super levees in Japan, Dutch engineers and landscape architects have developed the concept of Climate dikes or Delta dikes. These Delta dikes, thanks to their height, width or structural reinforcements should be that strong, that uncontrolled flooding is practically excluded. The Delta Committee has recommended to adopt this concept particularly in those dike ring areas which are most vulnerable to flooding.

Perspectives of technological developmentThe development of infrastructure in a sustainable manner is quite a challenge. Technological development may open new opportunities to enhance the functionality of infrastructural solutions. Technological development may also help to extend the life time of infrastructure and/or to develop more cost-effective designs and construction methods of infrastructure.

An important ‘source’ of innovations are the developments in information and communication technology. Advances in sensor and simulation technologies may promote the development of more accurate warning and forecasting systems. These technologies also support the development of local- and global-scale monitoring and diagnostic systems.

Integration of knowledge from various disciplines may open new applications too. For example a synthesis of knowledge from soil mechanics, chemistry and biology may generate a whole family of innovations. Using bacteria as ‘micro contractors’ there may be new opportunities for ‘on demand’ adaptation of soil characteristics. New materials may be eco-designed. The strength and stiffness of sand may be improved through the transformation into sandstone by bio-organisms. Saltwater seepage may be blocked by activating natural processes, and the effects of land subsidence may be reduced by better preserving soft soils such as peat. ‘Smart soils ®’ are a nice example of an eco-engineering approach which in due course will help to solve civil engineering challenges in deltas.

Information and

communication

technology is an

important ‘source’

of innovations

Information and

communication

technology is an

important ‘source’

of innovations

54

Box 3.9

Enhancing coastal safety by use of natural ecosystem engineers

Climate change involves rising sea levels and increased frequency and intensity of storms. Therefore, sustainable and cost-effective coastal protection is vital to low-lying coastal areas. Dikes and other civil-engineering structures are built for safety to flooding, but maintenance costs are high.

Salt-marsh vegetation is a good example of an ecosystem engineer: by reducing hydrodynamic forces, the vegetation traps and stabilizes sediments, leading to accretion, and reducing wave impact and flooding levels. Nowadays it is commonly known that dikes which are bordered by salt marshes require less height and enforcement. In the Netherlands, salt-marsh restoration is now combined with dike design in order to provide solutions, that offer nature value, sustainable safety and a flexible basis for future dike adaptations, with sufficient space for additional uses such as recreation. Basic to this integrated concept is the understanding of functioning of salt marsh systems on a larger scale and in the context of the whole ecosystem. Ecosystem engineers may be present in different zones, facilitating each other. Species in the higher zones of the salt marsh are facilitated by species in lower zones, that absorb the energy of incoming waves. The tidal flat in front of the salt marsh, in turn, influences the intensity of incoming waves and supply of sediments.

Intertidal flats can be inhabited by oyster reefs. The reef-building oyster beds could function as stabilising or protecting agents, because they reduce wave intensity and current velocity, and provide an extra sediment flux to higher tidal elevations. After initiation or transplantation of reefs, natural processes may stimulate their maintenance and expansion. The newly formed ecotope will generate a diverse habitat, supporting a biodiverse community.

55


California Bay

56

4.1 Modes in adaptation of land and water use

One of the trends in the development of deltas is an increasing awareness that occupation should be adapted to changing environmental conditions. Due to population growth, economic development and climate change the demands of land and water use will change. In particular the threat of climate change is an important trigger for adaptation of land and water use. This threat may be countered to some extent by regulation of spatial planning: promoting that (new) activities are located in low-risk areas to minimize the (increase in) vulnerability to climate change.

4. Development and adaptation of land and water use

5�

Development and adaptation of land and water use

If spatial planning offers little solace, solutions may be found in restructuring an area. For example in reconstruction of urban areas more space may be created for storage of excess rainfall. Urban flood management is another example. Finally at the lowest scale, vulnerability may be reduced through adaptive designs and construction methods. This may include amphibious housing, shifts to more salt-resistant cropping patterns, etc. This section describes a few examples of adaptation options.

4.2 Spatial planning and zoning

Historically environmental conditions played a major role in the spatial ‘planning’ of land and water use. The available natural resources as well as the transportation potential were major reasons to occupy deltas. Infrastructure development was necessary to take full advantage of the benefits deltas had to offer.

Due to the debate on climate change as well as the occurrence of some major floods in the past few years there is a trend to take better account of the limitations and risks posed by the natural system. For example there have been scenario studies in The Netherlands on spatial development. One of these scenarios included diverting new investments and urban development to areas with less or no flood risk. The new Delta Committee in its report, however, concluded that there is insufficient ground for such strategy. Even under severe unfavorable climate change scenarios, The Netherlands will be able to keep the water out with its flood control system, albeit with some additional measures. Therefore the Delta Committee recommended to increase the safety against flooding with a factor 10 above the existing high protection standard. This increase reflect the growth in the number of people and assets to be protected.

The awareness that deltas are potentially risky areas is nevertheless growing, the more so in view of climate change. But in practice there are hardly examples of formal risk based spatial planning. The UK, however, has regulations for spatial development and flood risks. the Planning Policy Statement 25 (PPS25) on Development and Flood Risks.

As yet there are

few examples of

risk based spatial

planning

As yet there are

few examples of

risk based spatial

planning

5�

Box 4.1

Regulation of spatial development in the UK

Since 2001 the UK has regulations for spatial development and flood risks: the Planning Policy Statement 25 (PPS25) on Development and Flood Risks. The aim of PPS25 is to ensure that flood risk is taken into account at all stages in the planning process to avoid inappropriate development in areas at risk of flooding, and to direct development away from areas at highest risk. The PPS25 defines what type of land use is compatible with particular flooding probabilities. PPS25 distinguishes three different zones with different flooding probabilities.

Zone 1 Low ProbabilityThis zone comprises land with a less than 1 in 1000 annual probability of river or sea flooding in any year (<0.1%). All uses of land are appropriate in this zone.

Zone 2 Medium ProbabilityThis zone comprises land with an annual probability between 1 in 100 and 1 in 1000 (1% – 0.1%) for river flooding resp. between 1 in 200 and 1 in 1000 (0.5% – 0.1%) for sea flooding The water-compatible, less vulnerable and more vulnerable uses of land and essential infrastructure are appropriate in this zone.

Zone 3a High ProbabilityThis zone comprises land with a 1 in 100 or greater annual probability (>1%) for river flooding resp. a 1 in 200 or greater annual probability (>0.5%) for flooding from the sea. Highly vulnerable uses should not be permitted in this zone.The more vulnerable and essential infrastructure uses should only be permitted in this zone carefully. Essential infrastructure permitted in this zone should be designed and constructed to remain operational and safe for users in times of flood.

Zone 3b The Functional FloodplainThis zone comprises land where water has to flow or be stored in times of flood. Only water-compatible uses and essential infrastructure should be permitted in this zone.

By the end of 2006 the role of the PPS25-guideline has been strengthened with respect to the obligatory character of its application in planning. Also the information on climate change impacts was refined.

5�


4.3 Urban (re)development

Economic development and population growth drive expansion of built up areas. This process is often leading to a reduction of available free space in cities and its surroundings. Urbanization leads to an increased tension between land and water development. Figure 4.1 shows the changes in land use for the city of Hanoi in the Red River Delta. Rural areas (agriculture and water) have been replaced rapidly by areas in use for mainly ‘urban’ purposes.

The augmenting rate of built up areas in cities leave less space available for water storage functions. This is an unfortunate situation in deltas as it increases the vulnerability for floods and droughts.

Often urban development means loss of agricultural land. In some cases agricultural land is so scarce and valuable that new land is reclaimed for urban development. An example are the plans for the development of Caofeidian Coastal City north of the delta of the Yellow River. Caofeidian Coastal City should become an ecological city build on islands in a lagoon.

Augmenting rate

of built up areas

leaves less space

for water storage

Augmenting rate

of built up areas

leaves less space

for water storage

Figure 4.1 Development of land use around the city of Hanoi

Urban

Bright vegetation

Dark vegetation

Marsh

Water

Road

Fallow

Wetland

Sand

60

Urban (re)development may also be combined with revitalization of flood protection works. In Japan conventional dikes are adapted to super levees (see Chapter 3). Apart from a more robust flood protection this adaptation provides usable space for urban (re)development with access to the waterfront.

Box 4.2

Development of Caofeidian Coastal City in the Yellow River Delta

In the Bohai Sea, in the delta of the Yellow River, a coastal city will be developed with an area of 150 km2. The city will house about 1 million people who will find work in a nearby port which is to be developed as well. It has been decided to built the city ‘offshore’ to safe valuable agricultural land in the delta. The choice for an offshore city brings design challenges with it. How to build a safe city in a low-lying area? How to maintain the characteristic mud flat coast?

Caofeidian Coastal City will not only be a new offshore city, it should also become an example of an ecological city. The city will be build on islands within a lagoon. Islands will be built a few meters above sea level with the sand that comes available from dredging the lagoon. The outer islands at the coast will protect the lagoon against flooding. Part of the water supply to the city will come from storage of local rainfall. The city design integrates coastal development with energy and water saving; an example of the Building with Nature philosophy.

Figure 4.2 Proposed lay-out of Caofeidian Coastal City

61


4.4 Adaptation to flood risks

‘Living with floods’In the Mekong delta, awareness of flood risks is very high. This is partly due to the frequency of flooding. On average there are major floodings every three years. This high frequency is due to limited protection by infrastructure. Also the large water volumes that have to be transported by rivers in the delta in the monsoon season play a role. The strategy of the Vietnamese government is to look for ways of local adaptation to (risks of) flooding:• the Land Use Law prohibits building in flood prone areas. • in terms of land use planning, residences are planned on safest grounds

(elevations) and preferably grouped together, which makes it easier to protect

• change in cropping calendars, use of salt-resistant crops (in areas where salinity intrusion is present) and flood-resistant production (floating rice and aquaculture)

• investing in upgrading of infrastructure.

Urban Flood ManagementOver the last decades there is a growing number of floods in urban areas. Climate change and rapid urbanisation will exacerbate this trend. Flooding incidents in urbanised catchment areas can lead to great public concern and anxiety and the economic impacts are often severe. Besides structural measures aiming at a reduction of the probability of flooding, new integrated approaches are being developed and implemented. Urban flood management aims to incorporate flood risk into urban (re)development and tries to increase robustness as well as the adaptive capacity towards future flood impacts

Urban Flood Management still faces a number of bottlenecks that hamper the adoption and effective implementation of flood risk management in urban planning practices. These include:• Lack of understanding of (residual) flood risks and their implications.• Lack of long-term and integrated planning.• Inadequate steering of local authorities.• Conservative nature of the building sector.

62

4.5 New agricultural practices to adapt to salinity problems

Salt accumulation in delta soils, resulting from intense irrigation and/or increased seepage, reduces the agricultural productivity Hence alternative practices are introduced to changing environmental conditions:• desalting of agricultural soils • genetic manipulation of existing crop species to enhance biological tolerance• cropping of salt tolerant species• mixed farming practices

Box 4.3

Agricultural practices for dealing with salinity problems in deltas

Rhine delta in The NetherlandsBrackish agriculture using salt-tolerant crops is a highly promising strategy for over 100,000 hectares of arable land below sea level in the Netherlands. The rising sea levels and different practices of water management mean that the soil in these areas is becoming increasingly salty. The return on normal crops is consequently falling sharply. Cultivation systems and market opportunities for salt-tolerant crops therefore provide new perspectives for agriculture in these regions.

Mekong deltaSome 800,000 ha (20% of the total area) in the Mekong Delta of Vietnam is affected by saline water with predominant freshwater in the rainy season and brackish water in the dry season. As saline water intrusion in the dry season is a major constraint to rice farming, many farmers develop an alternating rice-shrimp farming system. This system produces shrimp in the dry season and rice in the wet season on the same plot. In this farming practice saline water is used to flood the rice fields in the dry season to raise shrimp. At the beginning of the wet season, farmers flush salinity out of their fields using rain and fresh river water to plant rice. The integrated farming systems increase farmers’ income and improve the living standards of the local community.

ricefarming

increased water salinity and salt-affected periodsea

shrimpfarming

rice-shrimprotation

63


4.6 Adaptation to climate change

In a few years time adaptation to climate change has developed into an important field of research and policy-making. Many countries have developed National Adaptation Strategies. Restoration of the resilience of soil and water systems is a key component of such strategies.

Restoration of resilience in deltasDeltas are often confronted with coastal erosion, salt intrusion, subsidence, extreme high and low river discharges and changes in precipitation and evaporation. All these processes are affected by climate change, which makes deltas vulnerable to climate change. In many deltas the developments during the last few decades have modified soil and water systems. The area of surface water has become less, and so has the water storage capacity. Changes of

Nile Delta

64

land use, including the creation of impervious surfaces, have accelerated the rainfall-runoff process, making these areas more vulnerable to flooding. The resilience of natural systems (the capacity of systems to adapt to other conditions through natural processes) has generally deteriorated.

Adaptation to these changing conditions is a major challenge. Adaptation strategies should focus on restoration of the original resilience. Such strategies should include measures to enhance infiltration, retention and/or storage capacities of water systems. Adaptation in densely populated deltas may also include multifunctional use of areas, e.g. giving a water storage function to nature areas. Reducing the vulnerability of land use through adaptive designs is another important pillar of adaptation strategies, for example through urban flood management (see also section 4.4).

Development of adaptation strategiesMaking deltas climate-proof requires new adaptation strategies which are timely, technically sound, economically feasible and socially acceptable. However, both climate change and socio-economic developments come with large uncertainties. In order to develop adaptation strategies for climate-proof deltas, fundamental questions need to be answered, such as:• What are the requirements which the key economic sectors (e.g. agriculture,

transport, energy, tourism, industry) and nature put on water management and spatial planning in deltas?

• Under what circumstances do current strategies for water management and spatial planning fail to meet those requirements (when, where, how often)?

• What are the adaptation options that will allow us to keep on living and working in the deltas?

• How much time is available to implement these adaptation options for water management and spatial planning?

To answer such questions an integrated method is required to assess the vulnerability of deltas and to determine adaptation paths for the different sectors in deltas. One of the key-elements in such method is the so-called adaptation tipping point. An adaptation tipping point is a level where natural (physical) boundary conditions exceed technical, economic, spatial or societal acceptable limits. Figure 4.3 presents an example on the suitability of a delta for human settlement as a function sea level rise. The straight line represent conditions for the present adaptation capacity, the dotted line represent conditions under new adaptation strategies. The adaptation tipping points

Restoration of

resilience is the key

to adaptation to

climate change

Restoration of

resilience is the key

to adaptation to

climate change

65


are indicated as an (*). The risk of coastal flooding might at first be reduced to an acceptable level by intensified shoreline management. If that strategy reaches its limits it may be followed by the construction of new super levees. An adaptation tipping point identifies the point where a policy on water management or spatial planning needs to be revised and where a new strategy needs to be implemented.

Adaptation tipping points in system’s ability to cope with climate changeThe adaptation tipping points method (Deltares, 2008) takes the requirements of key sectors of water management and spatial planning as a starting point to identify the need for adaptation to climate change. The degree of climate change to which each key sector can cope is determined. Climate change scenarios are then used to show in which time period those adaptation tipping points may be reached. This provides insight into the vulnerability to climate change of deltas. Combining the adaptation tipping points with local scenarios will identify the vulnerability of a sector and the possible need for new adaptation strategies.

The timing of adaptation tipping points is crucial knowledge for decision makers. Knowing how long it will take before adaptation tipping points are exceeded makes the timeframe for decision-making explicit. The timeframe for a certain adaptive measure can be estimated by using climate change scenarios and socio-economic scenarios. Some adaptive measures will have to be implemented soon; others in the next 20 or 50 years or even later.

Adaptation

tipping points

identify when new

strategies are

needed to cope with

climate change

Adaptation

tipping points

identify when new

strategies are

needed to cope with

climate change

Figure 4.3 Examples of the relationship between natural boundary conditions and the

suitability of a delta.

66

The method may also help to develop a sequence of adaptations strategies, so-called, adaptation paths (Figure 4.4). Replacing Strategy 1 by Strategy 2 will happen at a certain level of climate change. It could even lead to a higher efficiency in use of the delta area. When the efficiency of the final strategy becomes too low, retreat from the deltas becomes unavoidable.

Figure 4.4 Adaptation paths to climate change for water management in delta areas.

Box 4.4

Adaptation tipping points analysis for Delta Committee

The adaptation tipping point method has been successfully applied to the water resources system of the Dutch Delta to support the analysis and recommendations of the Delta Committee. Research findings adopted in the report of the Delta Committee include:• Fresh water supply will be severely hindered through salt water intrusion; but it will not be an issue

before 2040• Speed of sea level rise (the higher scenarios) will come close or exceed the natural adaptive capacity

of the Wadden Sea• The Maeslant storm surge barrier in Rotterdam, has been designed for sea level rise up to 50 cm;

hence this will not be an issue before 2060• Current strategy for nature conservation will not be sustainable under climate change• Salt water upward seepage through the ground water is a minor effect• Coastal flood defense maintenance through sand nourishment will not be an issue, provided that

sand can be taken from the North Sea bed• In general it was concluded there are no limitations to technical adaptation measures, although

these measures become increasingly expensive and space consuming.

Strategy 1Strategy 2

Strategy 3

Climate Change / Sea Level Rise

Effi

cien

cy o

f a

da

pti

ve s

tra

teg

y

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Ganges-Brahmaputra Delta

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5.1 Role of governance in delta development

In the past few decades the development and management of deltas has become increasingly complex and often an issue of societal debate. A number of trends has added to this complexity, including decentralization of government and larger involvement of the private sector. Also interest groups and citizens have a stronger voice in development. They are able to delay or deter developments if these harm their interests. Sustainable development and management of deltas has to deal with this increased complexity; it

5. Governance of delta development and management

6�

Governance of delta development and management

calls for a strengthening of the governance structure. Good governance is in fact a permanent search for a proper balance between public and private interest, between efficiency and equity, between different regions and sectors, between economic development and environmental stewardship.

Box 5.1

Government and governance

The terms “government” and “governance” are widely used, sometimes interchangeably. There are, however, important distinctions between both concepts. Government can be defined as an institutional superstructure that society uses to translate politics into policies and legislation. The government’s foremost job is to focus society on achieving the public interest. Governance is the outcome of the interaction of government, the public service, and citizens throughout the political process, policy development, program design, and service delivery. Governance is a way of describing the links between government and its political, social, administrative environment.

Governments are specialized institutions that contribute to governance. Representative governments seek and receive citizen support, but they also need the active cooperation of their public servants. Governance is the outcome of politics, policies, and programs. The table below indicates the difference in character of both concepts.

Government Governance

superstructure functionality

decisions processes

rules goals

roles performance

implementation coordination

outputs outcomes

Source: International Tracking Survey Report ‘03

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Governance in the context of this researchGovernance has many dimensions: political, organizational, social and economic. In the context of this research, governance is related to creating the proper conditions for a sustainable development of deltas. Good governance should promote that plans and visions for delta development are actually brought into practice through development projects. Governance should also provide adequate arrangements for maintenance of infrastructure preventing early deterioration of the infrastructure.

The governance structure of deltas may be strengthened through different ways. 1. Promoting a better co-operation between different levels and sectors of

government taking into account trends of decentralization and the need for (national) coordination.

2. Facilitating the cooperation between government and the private sector taking into account trends of privatization but also the need to safeguard the public interest.

3. Better involving stakeholders and citizens in development and management issues to promote the societal acceptance of development projects as well the long term sustainability of development projects (arrangements and incentives for maintenance).

4. Creating arrangements for dealing with uncertainties and sharing of risks (insurance).

Different arrangements and mechanisms have been developed These arrangements and mechanisms are discussed in this chapter and illustrated with some examples.

5.2 Co-operation between levels and sectors of government

Lack of co-operation between different levels and sectors of government are a major impediment for implementation of development projects. Hence the interest in multi-level governance to overcome these impediments. The trend of decentralization constitutes a major trigger for the strengthening of the governance structure through multi-level governance.

Growing environmental concerns may lead to a standstill in economic development activities. Exploitation of natural resources may be hampered

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or prohibited because of expected environmental impacts. The same can be observed for port development (e.g. extension of the Port of Rotterdam) or deepening of navigation channels (Western Scheldt, entrance to the Port of Antwerp). Widening the policy field with the field of nature development or regional development may open new opportunities, e.g losses in environmental values in the project area may be compensated elsewhere.

Both Integrated Water Resources Management (IWRM) and Integrated Coastal Zone Management (ICZM) have evolved in the past decade(s) into well-established management approaches for river basins and coastal zones. In deltas the coastal zones and river basins do meet. Linking the management of river basins and coastal zones is needed to maintain or improve the ecological integrity and socio-economic viability of coastal and marine areas.

jakarta

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These modes of improved co-operation between levels and sectors of government will be illustrated with some examples.

Multi-level governance: co-operation of national, regional and local scalesPlanning of delta development requires harmonization of different interests. Often trade-offs have to be made between different regions and/or sectors. Given the regional scale of deltas and their role in the development of national economies, there is also the need for (national) coordination of development activities.

The actual implementation of a programme of measures requires co-operation of different levels and sectors of government as well as the private sector. Hence the need for a platform for structured communication and negotiation between all parties involved in delta development. The foundation of the Delta council in the Southwestern Delta of the Netherlands offers a nice example of such multi-level governance (see Box 5.2).

Box 5.2

Foundation of a Delta council in the Southwestern Delta of the Netherlands

Some years ago the provincial managing authorities have drafted a vision for the future. This vision deals with both the ecological side effects of the Delta Works and the expected impacts of climate change. Restoration of estuarine dynamics has a prominent place in this vision. To promote and facilitate its implementation the Delta council was founded at the end of 2004. Members of the Delta council are the provinces of Zeeland, North Brabant and South Holland and the Ministry of Transportation and Water Management, the Ministry of Agriculture, Nature and Food Quality, and the Ministry of Housing, Spatial Planning and the Environment. Municipalities, water boards and interest groups are involved through an advisory group.

First step in the implementation of the vision is the determination of a Delta programme. The Delta programme aims to protect and reinforce the ‘delta values’ at risk. The programme is being prepared by a so-called ‘Programme Bureau’, which consists of experts and representatives of the parties which make up the Delta council. The main challenge of the bureau is the determination of the programme of measures for a sustainable and climate proof development of the Southwestern Delta and its implementation in close cooperation with the parties involved.

Multi-level

governance for

better co-operation

in a decentralized

world

Multi-level

governance for

better co-operation

in a decentralized

world

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Widening the policy fieldGrowing environmental concerns may lead to a standstill in economic development activities. Licenses for exploitation of natural resources may be denied in fear of jeopardizing sensitive delta ecosystems. Widening the policy arena with e.g. regional development may turn out to be an effective way to overcome objections against such exploitation. The extraction of natural gas from the Wadden Sea (The Netherlands) offers a good example for such strategy.

Box 5.3

Regional development and the extraction of natural gas from the Wadden Sea

Natural gas has been extracted in the Wadden Sea Region since 1987. The gas extraction, however, has been the subject of political and social discussion for many years. Objectors feared that mud flats, shallows and salt marshes would slowly but surely ‘drown’ due to subsidence. Although an extensive study in 1999 showed that the effects of gas extraction were most likely very minimal, the Dutch Government decided not to allow any new gas extraction at that time. The call for gas extraction, however, remained.

In September 2003, the Council of Ministers resolved to appoint an independent Expert Advisory Group to provide advice regarding policy decisions in the areas of nature, fishing and gas extraction in the Wadden Sea. This Wadden Sea Expert Advisory Group, also referred to as the ’Meijer Commission’, published its final report in April 2004. The Expert Advisory Group arrived at the conclusion that there are no environmental objections to the extraction of gas. The effect of subsidence will be more than compensated for by the supply of sand. The committee, therefore, recommended to allow the extraction of natural gas. Extraction must be restricted or stopped, however, if it becomes apparent that subsidence exceeds certain values. The committee recommended also that a significant portion of the revenues from gas extraction should be invested in the natural environment and the economy of the northern Netherlands.

Many of the recommendations made by the Meijer Commission can be found in the Wadden Policy, presented by the Dutch Cabinet in June 2004. The Dutch Cabinet also decided to set up a Wadden Fund. A total of 800 million euro will be deposited from the treasury over a period of twenty years to increase the size of the Wadden Sea nature reserve region, strengthen its ecology and stimulate sustainable economic development in the Wadden Sea Region.

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Also the recent history of flood protection along the river Rhine has shown the strength of widening the policy field. In the case of the river Rhine impediments in the implementation of dike reinforcements were overcome through inclusion of nature development in the strategy for flood protection.

Linking river basin management and coastal zone managementSince the UNCED Conference in Rio de Janeiro, the link between river basins and coastal areas have been increasingly highlighted in several fora. Two key management approaches have been promoted in the post UNCED years to promote sustainable development of river basins and coasts: Integrated Water Resources Management (IWRM) and Integrated Coastal Zone Management (ICZM). The concepts of IWRM and ICZM have been developed rather independently from each other by separate management organisations, frequently with different objectives and modes of operation. Often estuaries and coastal areas were not considered to be part of the river basin.

The IWRM paradigm encouraged a shift from single sector water planning to multi-objective planning and integrated consideration of land and water resources. IWRM also recognizes the wider socio-economic and development goals and promotes cross-sectoral coordination. ICZM is a process by which rational decisions are made concerning the conservation and sustainable use of coastal and ocean resources and space. The process is designed to overcome the fragmentation inherent in single-sector management approaches (such as fishing operations, oil and gas development). The last ten years have made clear that the advancement of coastal or river basin issues cannot be solved by ICZM programmes and river basin management (RBM) programmes working in isolation. Linked management is often the only realistic way to maintain or improve the ecological integrity and socio-economic viability of the coastal and marine areas. Recently, the linked management of river basins and coastal and marine areas is recognized to be a characteristic feature of an Ecosystem-based Management. This is also illustrated by the recent publication Ecosystem-based Management: Markers for Assessing Progress (UNEP/GPA, 2006).

Widening the policy

field may open

new opportunities

for project

implementation

Widening the policy

field may open

new opportunities

for project

implementation

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Box 5.4

Creating an enabling environment to restore ecosystem benefits in coastal and estuarine areas of the Incomati River (Southern Africa)

The water resources of the Incomati River Basin, shared among South Africa, Swaziland and Mozambique are heavily overexploited. With continued population growth and urban and industrial development, water demand in the basin continued to grow and it has by far surpassed the water available in the basin. The downstream part of the basin has significant ecological and socio-economic importance: the Incomati estuary is a nursery for commercial important fisheries including shrimp and a breeding ground for various aquatic birds. The productivity of the Maputo Bay depends largely on the freshwater input from the Incomati river.

Hence, there is a need to build consensus and a shared vision on the river’s future development; a vision that incorporates the basic principles of equity and sustainability in the water allocation and management of the river basin. Since 1983, with the establishment of the Tripartite Permanent Technical Committee (TPTC), several measures have been taken to create an enabling political and technical environment for negotiations towards linked river basin and coastal area management in the Incomati basin. A main challenge to linked river basin and coastal area management, however, still includes an improved understanding of the linked river basin and coastal systems. Water allocation is often based solely on the water demand for domestic use, agriculture and power production. A better insight is needed in the ecological river flow requirements. Application of existing methods for determination of ecological river flow requirement should support the political negotiating process.

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5.3 Cooperation between government and private sector

Co-operation between government and the private sector may cover various fields. Co-operation in the development and management of infrastructure through public-private partnerships is a well-known example. But co-operation may for example also include joined developmet and sharing of knowledge. This section discusses a few examples.

Public-private partnerships in implementation and managementEconomic growth in Delta regions depend on provision of adequate service of water, sanitation, energy and urban infrastructure and telecommunication. The financial resources of governments are often insufficient to provide the needed services. Public financing is often volatile due to macroeconomic instability, growing investment requirements and inefficient tax revenues. As a consequence public financing may not meet crucial expenditure requirements in a timely and adequate manner. Also the technical capacity may be lacking, forcing governments to consider alternative options of finance and technical support. This may be achieved through associations with the private sector on a project-to-project basis in public-private partnerships (PPP).

The private sector may tap a large pool of funding sources. Public-private partnerships aim to blend the access to finance, innovations, knowledge of technologies, managerial efficiencies and entrepreneurial spirit with the social responsibility, environmental awareness and local knowledge of the public sector. Public–private partnerships include many options for cooperative provision of services as alternative to the delivery of traditionally public domain services (World Bank, 1997).

• Corporatization: The assets of a government department are transferred to a corporation with the government as the sole shareholder.outside private lenders can finance operating and capital budgets)

• Service contract: Under this option, the private sector performs a specific operational service for a fee.

• Management contract: With this option, the private sector is paid a fee for operating and maintaining a government -owned business and making management decisions.

• Lease: Under the lease option, the private sector leases facilities and is responsible for operation and maintenance.

• Concession: Under concessions, the private sector finances the project and

��


also has full responsibility for operations and maintenance. The government owns the asset and all full use rights must revert to the government after the specified period of time.

• Build own transfer (BOT) / build own operate (BOO), build own operate transfer (BOOT): BOT, BOO and BOOT arrangements are similar to concessions but in this case the private sector owns the asset and receives a fee for the service direct from the users.

• Divestiture: This option can take two forms – partial or complete divestiture. A complete divestiture, like a concession, gives the private sector full responsibility for operations, maintenance and investment, but unlike a concession, a divestiture transfers ownership of the assets to the private sector

Risks associated with PPP’s usually relate to long term commitments with often unsure political commitments and economical situations. Risk allocation is a very important aspect of the public private partnerships and this is often one of the decisive factors on the choice for the appropriate private sector participation. Although the principle is to transfer the risk to the party that is

Approach Asset Ownership

Operation & Maintenance

Capital Investment

Commercial Risk

Contract Duration

Service Contract

Public Public/private Public Public 1-2 years

Management Contract

Public Private Public Public 3-5 years

Lease Public Private Public Shared 8-15 years

Concession Public Private Private Private 25-30 years

Build-Operate-Transfer (BOT)

Public and Private

Private Private Private 2-30 years

Divestiture Private or public and private

Private Private Private Indefinite or limited by license

��

best able to manage them, cooperative risk sharing becomes more and more important.

The unavoidable transfer of some risk/responsibility from the public to the private sector in PPP schemes also poses a serious challenge to transparency and the wider issue of public accountability whereby access to publicly-relevant information including processes of decision-making can be constrained by “commercial-in-confidence” clauses and highly-technical language. To overcome this issue there is a tendency that separate authorities are established for quality control activities and public disclosure, to assure guaranteed delivery of goods and services.

Co-production of knowledge Government and the private sector may also join forces in the development of knowledge. An example is the ‘Building with Nature’ research programme in The Netherlands. The research programme aims to develop the required knowledge for a more realistic and practical incorporation of environmental

Risk allocation is an

important aspect of

the public private

partnerships

Risk allocation is an

important aspect of

the public private

partnerships

Box 5.5

Maasvlakte-2 land reclamation for Port of Rotterdam

Directly to the west of the current port and industrial area of Rotterdam, a new location for port activities and industry is being created in the North Sea: Maasvlakte 2. The land reclamation will measure around 2000 hectares in total. Half of this will consist of infrastructure, such as sea defenses, fairways, railways, roads and port basins. The other 1000 hectares will provide the space for industrial sites. The project is a joint venture by the Ministries of Transport and Public Works, Housing, Spatial Planning & the Environment, Economic Affairs, Agriculture, Nature & Food Quality and Finance, Rotterdam metropolitan region, the municipality of Rotterdam and the province of South Holland.

The construction of this new port and industrial area is part of the Rotterdam Mainport Development Project (PMR). This is a project that strengthens the main port whilst, at the same time, aims to improve the quality of life in the region. Maasvlakte 2 will be created in stages. Maasvlakte 2 is being realised on the basis of Design & Construct; i.e., the contractor hired by the Port of Rotterdam Authority will receive an integrated contact. He will thus be responsible for the design and implementation as well as for the risks involved.

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considerations in planning and design (see also Box 3.5 for an outline of this research programme).

‘Building with Nature’ was initiated by Dutch contractors. The government sponsored research programme is being carried out by a joint venture of Dutch industry, engineering consultants, specialist institutes and universities. A key objective is to develop new design and assessment methods based on scientific insights in the working of ecosystems and to share these with parties involved in the assessment, development, construction and exploitation of hydraulic engineering projects. The new insights from Building with Nature should promote that policy and regulations will be based on in-depth knowledge and insights, more than is currently the case. This should make policy and regulations more effective, from which ecology and economy should both benefit.

5.4 Involvement of stakeholders and citizens

Involvement of stakeholders and citizens is important to promote societal support for development projects. Such participation is a precondition for sustainable development if the success of proposed measures depends on the active co-operation of stakeholders and/or citizens. If people are requested to adapt their conduct in a more sustainable way, it is essential that they understand the need of such adaptation as well as their possibilities to do so. Involvement of stakeholders is also of great importance in the maintenance of infrastructure. To prevent early deterioration of infrastructure, its maintenance should be well organized. Also sufficient funds should be (made) available for carrying out maintenance. Money for such funds should be raised from the people and companies that have a stake in the proper functioning of the infrastructure.

Stakeholders and citizens do possess of a lot of (tacit) knowledge on the functioning and use of water resources systems. Such knowledge constitutes important input into social learning processes for planning a more sustainable development of deltas. This section presents some examples of stakeholder involvement in flood management and water supply.

Raising public awareness to promote a more sustainable conduct of citizens To solve or alleviate water resources problems in a sustainable way both

Public participation

is a precondition

for sustainable

development

Public participation

is a precondition

for sustainable

development

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structural and non-structural measures are needed. For example flooding problems may be alleviated by enlarging the drainage capacity of rivers or canals. However, much of the benefits of dredging a city’s rivers and canals might be short-lived if this investment is not linked with improved public services in solid waste, land-use, (low-income) housing, creation of employment opportunities, etc.

Stakeholders are often not only part of the flooding problems but also part of the solutions. Hence, the need to stimulate the participation of stakeholders to develop a balanced mix of structural and non-structural measures. Box 5.6 presents an example of citizen’s involvement in flood management in Jakarta.

Box 5.6

Citizen’s involvement in flood management in Jakarta (Indonesia)

Floods are an increasingly serious threat in Jakarta. Heavy downpours during the rainy season flood the city. Water from the Ciliwung-Cisadane River Basin flows into the vulnerable, densely populated delta area. About 40% of Jakarta consists of lowland area; land subsidence is aggravating the flooding problem. The ‘reclamation’ of flood plains, retention areas, lakes and ponds for residential and commercial purposes further increases the risk of floods.

To alleviate flooding problems various kind of measures have been taken, mainly of an engineering nature (“structural approach”). These interventions were initiated and managed by central government agencies. The measures did not yet include provisions for ‘non-structural’ solutions. Many stakeholders are, however, not only part of the flooding problems but also of the solutions. Hence, non-structural measures are an essential component in a strategy to alleviate flooding problems. Non-structural measures can range from changing people’s perception that floods can be fully prevented (changing existing perceptions and raising awareness towards flood risk) to better spatial planning [improved flood plain management, flood plain zoning, flood proofing measures], better solid waste management, better control of issuance of building permits, etc.

Non-structural measures are hard to implement through top-down interventions, with the central Government taking full responsibility. An effective decentralization to stakeholders with complimentary responsibilities is needed to trigger participation and to develop a balanced mix of structural and non-structural measures. The Government’s role is then to bring these stakeholders together, create mutual trust, build partnerships, and stimulate participation.

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Social learningSocial learning processes play a central role in public participation. Social learning basically means learning together to manage together (HarmoniCOP, 2005). Stakeholders are assumed to manage together since, no one has all the necessary legal, financial, social or technical knowledge to do this on their own. The processes, based on dialogue, aim to arrive at a shared understanding of the issues at stake and of possible solutions to reach an agreement and to pool resources to implement this agreement.

Box 5.7

Social learning in project on fresh water supply to Tholen (The Netherlands)

In several areas in the Delta-region in the southwest of the Netherlands, the ecological quality decreased due to the Delta Works (see e.g.: Borger 2004; Colijn and Binnendijk 1998; d’Angremond 2003). Among the ecological problems in the Delta-region is the excessive growth of blue-green algae in one of the freshwater lakes that were created: the Volkerak-Zoom lake. To improve the ecological quality of this lake, the Dutch government regards the restoration of estuarine dynamics in the area as the most promising solution. However, the restoration of estuarine dynamics will affect the farmers in the surrounding areas, who use freshwater from the lake for agricultural purposes. That is why the Delta Council (see also Box 5.2) initiated a fundamental discussion with a range of actors on the integration of a more natural Delta and a more natural, sustainable freshwater situation for agriculture.

The discussion took shape in the pilot-project ‘Fundamental discussion on the freshwater supply for agriculture on Tholen & St. Philipsland’. The objective of the pilot-project was to have a fundamental discussion with all relevant actors and to obtain a shared insight and agreement on the sustainable development of ecology, economy and society in the Delta region (Reijs, 2006 a,b). Participating actors in the fundamental discussion were (representatives from): local farmers; an agricultural interest organization; agricultural business; national, regional and local nature societies; local and regional water managers; local, provincial and national public servants and delegates. The process design consisted of successive diverging and converging rounds of three plenary and several small-scale meetings.

The participatory process, using social learning processes, appeared to be very successful and was much appreciated by all stakeholders (Hommes et al, 2008). The pilot-project will be succeeded by two other case studies in the area, based upon the same approach and dealing with the same issues.

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5.5 Approaches for dealing with risks and uncertainties

Development of deltas is faced with many uncertainties, among these the speed and extent of climate change. This explains a growing interest in risk management and other approaches for dealing with risk and uncertainty in a structured and systematic way. Flood risk management is no longer limited to flood prevention but looks into the whole safety chain, including impact reduction through spatial planning (pro-action), emergency management (response) and insurance against natural hazards (recovery). Also ‘new’ management approaches such as ‘adaptive management pay explicit attention to uncertainties. This section looks into some examples of emergency management and adaptive management.

Emergency managementFlood risk management aims to minimize the probability of flooding and/or the impacts of flooding (both casualties and damage). In The Netherlands the focus has always been on prevention of flooding through flood defenses. There is, however, a growing awareness that it is worthwhile to prepare for the unfortunate event that a flood occurs. This awareness was especially triggered by the flooding disaster in New Orleans due to hurricane Katrina. In 2007 and 2008 much effort has been put in drafting emergency rescue plans. The efforts culminated in November 2008 in the nation wide exercise ‘Waterproof’.

Box 5.8

Flood risk management in coastal Louisiana

The Louisiana’s Comprehensive Master Plan for a Sustainable Coast (2007) indicates that levees are not the answer for every south Louisiana community. Since there are not enough federal dollars or available land to build levees everywhere flooding occurs, the Master Plan highlights ways in which citizens themselves can reduce their risks. The plan recommends that citizens take advantage of the Community Rating System, which can help homeowners reduce their insurance premiums if they raise or retrofit their homes. Making sure their communities curtail development in wetlands and flood prone regions is another measure that can lower flood risks as well as premiums. The plan’s emphasis on non-structural solutions highlights the role citizens of the coast can play in making south Louisiana a safe place to live and work.

There is a growing

awareness of

the importance

of emergency

management

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The wider scope of flood risk management can also be found in the European Flood Risk Directive. It also implies another distribution of responsibilities. Whereas flood prevention is basically a government responsibility, reduction of impacts is a joint responsibility of government and citizens. This is illustrated by the approach to flood risk management in coastal Louisiana (see Box 5.8)

Dealing with uncertainties through adaptive managementAdaptive management may be defined as an iterative process of optimal decision making under uncertainty. It has the aim of reducing uncertainty over time via system monitoring. Adaptive management is often characterized as “learning by doing” although it is more about deliberate experimentation. Examples can be found in the large scale beach nourishment strategy proposed by the Dutch Delta Committee. This strategy is facing important uncertainties with respect to the effectiveness of large scale sand nourishment as well as the extent of sea level rise. The type of measure, however, lends itself good for adaptation based on the findings of monitoring. The Thames Estuary 2100 project in the UK is another example of adaptive management: the strategy for flood risk management will vary depending on the expectations of sea level rise.

Rhine River Delta

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Box 5.9

Thames Estuary 2100: adapting to sea level rise

Climate change will cause sea levels to rise and will also affect the scale and frequency of tidal surges, but there is uncertainty on the nature of this change. Thames Estuary 2100 is looking at how to manage tidal flood risk through the century. It includes an assessment of the useful life of the existing defenses as well as the development of an understanding of the ‘drivers’ for change in the estuary (i.e. climate change, urban development, social pressures and the environment);

The plan will be adaptable to climate change and to a changing estuary. Depending on the scenario for sea level rise various types of measures are being considered, including raising of existing embankments and the construction of a new barrier. Figure 5.1 shows a number of strategies over time in relation to projected sea level rise.

Figure 5.1 Sea level rise strategies for the Thames Estuary

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Nile delta

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6.1 Two conflicting perspectives on development of deltas

Basically there are two different ways to respond to the different drivers and trends. The first strategy is very much driven by the (liberal) economic perspective: the role of the (central) government is reduced through privatization and decentralization. Also there is less government influence in spatial planning, etc. The conflicts that could arise out of this economic focus are solved in a typically technocratic way: i.e. by further development of infrastructure. This perspective reflects a high belief in our capabilities to shape the world to our needs. The long term sustainability however is

6. Way forward?

��

Way forward?

not guaranteed. Changing environmental conditions will require a regular upgrading of the infrastructure, as infrastructure does not adapt naturally.

The second strategy, i.e. the environmental perspective, is driven by global concerns on climate change and environmental degradation. It reflects a growing awareness that nature poses limits to development. These limits may be stretched to some extent through the development of infrastructure but at increasing costs. In this strategy land and water use should in stead be adapted to changing environmental conditions through regulation of spatial planning and adaptive designs. Natural processes should be utilized as much as possible to adapt to changing environmental conditions. The environmental perspective aims to make better use of the inherent adaptive capacities of nature.

Box 6.1

Economic and environmental perspectives in the eight selected deltas

In the Yellow River Delta development is driven by strong economic sectors, such as the oil industry. Government is clearly visible through central planning. There is a growing environmental awareness for concern, although as yet still weakly expressed.

The Government of Vietnam has identified the Mekong Delta as a priority area for economic development. The target is to increase the production of food, commodities and consumer goods by 8% per year. Privatization is emerging amidst central planning and age-old social structures. Environmental concern is as yet rather weak, but people have learned to live with river floods.

In the Ganges–Brahmaputra Delta the economy is struggling to keep pace with a growing population. There is still a great need for basic infrastructure (roads, bridges, embankments, power and irrigation systems), being provided by a (highly centralized) government. Environmental concern is still rather weak, but people have learned to live with floods.

Delta development in the Ciliwung River Delta is driven by very high urbanisation growth (Jakarta). Government is currently in a decentralization process. Already in 1984 the Government devised a “Jakarta Out” strategy for expansion of the city to areas that are less environmentally critical. However, this sensible plan soon lost out to commercial interests.

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The economic perspective is visible in most deltas of the world; also in the eight selected deltas (see Box 6.1). The environmental perspective is, as yet, less visible, but is gaining momentum. We see this for instance in integrated water management and coastal zone management. Ideas to reconcile human development with nature are emerging in various fields. Building with nature is practiced in the form of beach nourishments as opposed to hard structures to control erosion. Multifunctional use of infrastructure is being implemented in densely populated deltas, to save space and money. Restoring the natural purification capacity of wetlands and estuaries are being considered in highly modified deltas, as in the Netherlands. Renewable energy from waves, tides and salinity gradients is being studied.

The two perspectives are basically conflicting. The main challenge therefore is to combine elements from both perspectives into a strategy which is both economically viable and ecologically sound.

In the Nile river delta the economy is struggling to keep pace with the growing population. Privatization, trade liberalization and deregulation are current issues in structural reform. Environmental concern is still rather weak.

The Rhine River Delta comprises a consolidated diversified economy (industry, ports and transport, services, agriculture) in a largely man-made delta. Decentralization and public participation have largely replaced traditionally central planning procedures. Environment is included in planning and legislation framework. New visions include Room for rivers, Dynamic estuaries and Building with Nature, the implementation of which are slowly progressing.

Delta development in the Mississippi River Delta is mainly driven by strong economic sectors, notably the oil industry. The (Federal) government traditionally operates at a certain distance Environment is included in planning and legislation framework (e.g. coastal Wetlands Planning, Protection and Restoration Act of 1990). There is a strong lobby of nature groups.

In California Bay delta development is mainly driven by strong economic sectors, notably agriculture. (Federal) government traditionally operates at a certain distance. The current governance structure for water includes more than 200 federal, state, and local government agencies with some jurisdiction in the Delta. Everyone is involved but no one is in charge. Environment is included in planning and legislation framework. There is a strong lobby of nature groups. Efforts are made in increasing water efficiency of sectors. The new Delta Vision Strategic Plan (October 2008) acknowledges co-equal goal of restoring the Delta ecosystem and creating a more reliable water supply for California.

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Way forward?

6.2 Enabling the sustainable development of deltas

The characteristics, which make deltas attractive areas to live and work, are under increasing stress due to population growth, economic development and climate change. The management of delta development has also become increasingly complex, due to a.o. decentralization and privatization. Worldwide concern over a changing climate and environmental degradation has raised the environmental awareness that nature poses limits. A sustainable development of deltas, however, requires not only acceptance of the limits posed by the natural system but also making use or even enhancing its enabling conditions. A few questions need to be answered in this respect:• what development are we pursuing, how do we strike a balance between

economic development and environmental stewardship• what are our technical capabilities and how much confidence do we have in

them (knowledge/science/engineering experience) and • how are we organizing these capabilities vis-à-vis the social environment

(governance).

To promote sustainable development of deltas a clear vision has to be developed on how to respond to the various drivers of change as well as on how to play along with the various trends in society. Innovations are required to implement such vision, these include social, institutional and technological innovations.

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6.3 Delta vision: a shared view on delta development

A shared vision on sustainable delta development should deal with all drivers for change in a delta (population growth, economic development, and climate change) as well as with the relevant societal trends (decentralization, privatization, participation, growing environmental concerns and growing risk aversion). Such vision should be developed in close co-operation with all parties that have a stake or a say in the development of the delta. A good example of such vision is ‘‘Delta in Sight’ which was developed for the Southwestern delta of The Netherlands and presents an integral view on problems and possible solutions for the Dutch Delta waters.

Next the delta vision should be elaborated into a policy or delta programme. Such programme cannot be limited to infrastructural measures or restoration measures only. A sensible combination of different kind of responses is required. This will include measures for restoration of natural systems, adaptation of land and water use, extension of infrastructure as well as measures to strengthen the governance structure. Extension of infrastructure may be needed; in particular in those cases where the adaptive capacity of land and water use and/or the potentials of the natural systems are insufficient. In order to be more sustainable, the development of infrastructure should be tuned to these (new) demands, e.g. through more robust infrastructure and multi-functional use of infrastructure. Also the development of infrastructure has to be in harmony with the potentials and limits of the natural system, e.g. through building with nature.

Establishing the most suitable combination of measures requires a strategic analysis of the potentials and limitations of the different types of measures. The analysis should also look into the coherence and timing of these measures. Moreover, such analysis should take account of the many uncertainties associated with delta development, including the impacts of climate change. Strategic Impact Assessment, being a systematic process for evaluating the environmental consequences at the earliest stage of decision-making on a par with social and economic considerations, may constitute a suitable instrument for the development of the shared delta vision and the associated delta programme. Strategic impact assessment should be applied at all levels, to assess strategic decisions at plan, program and policy level in key sectors with potentially significant effects such as transport, energy, agriculture, water management, fisheries, infrastructure, spatial planning and nature.

Strategic impact

assessment: an

instrument for

development of a

shared delta vision

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Way forward?

6.4 Delta technology: innovations in science and technology

Sustainable development of deltas requires innovations in the knowledge of natural systems behaviour as well as in the approach to planning and design. A number of required breakthroughs have been identified in the Dutch innovation program ‘Building with Nature’.

An important ‘source’ of innovations are the developments in information and communication technology. Advances in sensor and simulation technologies may promote the development of more accurate warning and forecasting systems. These technologies also support the development of local- and global-scale monitoring and diagnostic systems.

Integration of knowledge from various disciplines may open new applications too. For example a synthesis of knowledge from soil mechanics, chemistry and biology may generate a whole family of innovations. Using bacteria as ‘micro contractors’ there are opportunities for ‘on demand’ adaptation of soil characteristics. New materials may be eco-designed. ‘Smart soils ®’ are a nice example of an eco-engineering approach which in due course may help to solve civil engineering challenges in deltas.

Table 6.1 Required breakthroughs in innovation programme ‘Building with Nature’

Knowledge of natural system behavior: Approach to planning and design:

• static approach ➞ dynamic behaviour

• descriptive ➞ predictive

• species ➞ ecosystem dynamics

• false certainty ➞ living with uncertainties

• engineering-centered ➞ integral thinking

• mitigating adverse environmental effects ➞

adaptation to the natural system

• construction ➞ life cycle management

• reactive ➞ pro-active

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6.5 Delta governance: social and institutional innovations

For development of deltas to be more sustainable, it is important to obtain societal acceptance and support for this development. Good governance should promote that shared visions are developed on sustainable development of deltas. Moreover proper conditions should be created for the actual implementation of such a vision through development projects. Governance should also provide adequate arrangements for maintenance of infrastructure to prevent early deterioration of the infrastructure.

Societal trends have to be taken into account in creating these conditions, in particular the trends of decentralization and privatization. Decentralization and privatization may be viewed as autonomous developments. The challenge is to utilize the advantages of both trends, while addressing their undeniable drawbacks. This calls for a selective enhancement of governance structures, reflecting the regional scale, integrated nature and long term perspective of delta development. The enhancement may take different modes:• Promotion of a better co-operation between different levels and

sectors of government taking into account trend of decentralization and the need for (national) coordination.

• Facilitation of the cooperation between government and the private sector, taking into account trends of privatization but also the need to safeguard the public interest in the long term.

• Better involvement of stakeholders and citizens in development issues to promote the societal acceptance of development projects as well the long term sustainability of development projects (arrangements and incentives for maintenance).

• Creation of arrangements for sharing of risks (insurance) and financing (securing funds for maintenance and broadening the base for investments).

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Way forward?

6.6 Delta dialogue: establishing best delta practices

Sustainable development of deltas is an increasingly complex field which requires the contribution and cooperation of many parties. Although there is no general recipe on how to deal with many delta issues, it is important to learn from experiences elsewhere. To this end, exchange of knowledge and experiences should be stimulated. Such exchange may take various forms:• The draft National Water Plan of The Netherlands (December 2008) proposes

to set-up an active and longstanding cooperation on water safety and water quality with some four delta areas in the world. This cooperation may serve as a vehicle for exchanging experiences in planning and design approaches

• The Aquaterra Conference has the ambition to develop into a biannual forum on delta and coastal development. The conference may offer a platform to discuss the various challenges in deltas and the possible approaches to deal with these challenges. Through a process of dialogue, these approaches may be elaborated into best delta practices.

Sustainable

development of

deltas is stimulated

by exchange of

knowledge

�4 Mekong Delta

Box 6.3

Emerging ‘best practices’ for dealing with delta issues?Deltas have characteristics in common, but there is much diversity in physical conditions, governance structure and cultural background. Hence, there is no general recipe on how to deal with delta issues. Nevertheless, some broad perspectives may be distinguished on dealing with these issues: emerging ‘best practices’ for deltas?

Relieving the pressure on available space. Spatial planning regulation may relieve some of the pressure by redirecting urban development and economic activities to less ‘busy’ areas and/or low risk areas. Another option is land reclamation, which offers good opportunities for implementation of the Building with Nature concept, meanwhile easily applying new safety considerations.

Improving resilience of delta areasVulnerability of societies to the hazards to future climate change (such as flood risks, droughts and salinity intrusion) should be reduced, preferably by making societies more resilient. Resilience can be improved by: preparedness, coping strategies and adaptation to changing conditions. This requires a combination of willingness to change, appropriate technology and community participation.

Securing fresh water supplies.Many deltas in the world currently face water shortages which may aggravate due to climate change and pollution. Adaptation of land and water use will be an important way to respond to these shortages. This may include more efficient water use and /or changes in cropping pattern and fertilization in agriculture. Pollution reduction programmes and establishment of environmental flow requirements for deltas are needed. Their implementation may benefit from involvement of river basin agencies.

Upgrading of ageing infrastructureMany deltas have irrigation and drainage systems as well as infrastructure as flood protection works, roads and supply and treatment workd, which require upgrading. Public private partnerships could provide a solution in those cases where farmers, industries and communities directly benefit from these infrastructure investments. But for protection schemes against floods and storm surges other options could be more appropriate, such as introducing financing mechanisms.

Coastal erosion managementMany deltas experience coastal erosion problems due to a sediment shortage Solutions should preferably include a restoration of the sediment balance. If this is not feasible, sand nourishments are preferred over hard engineering structures. Also other ‘Building with Nature’ options should be

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Way forward?

looked into, e.g. mangrove restoration. This is primarily a task for coastal management agencies, who should work closely together with local stakeholders and the private sector.

Biodiversity protectionWorldwide estuarine ecosystems and biodiversity in deltas are under severe pressure. Effective action must be taken to protect nature areas, both from local habitat destruction and from external disturbance and adverse inputs (pollutants). This requires adhering to the national and international obligations such as Habitat Directive, Ramsar Convention and Biodiversity Convention. Biodiversity protection should be effectuated at the local level through cooperation and involvement of all stakeholders.

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deltares trends & responses of 8 deltas

Documents

planning of delta development

delta governance

coastal development

values of deltas

selected deltas

delta dialogue

delta technology

delta vision