Solving delta dilemmas
Thursday, 29 April 2010
Changes in the coming decades are expected to result in no less than 80% of the world's people living in urban areas adjacent to coasts or major rivers. However, space is at a premium and waterside locations present threats as well as opportunities. Especially in view of expected climate changes, the world faces a number of challenges in this respect. The Netherlands has solutions to offer, both at home and abroad.
Living in coastal regions and deltas is a risky business. The Netherlands is vulnerable not only to flooding, but also to water depletion, shortages of groundwater, subsidence, salt intrusion and pollution. A nation struggling to accommodate over 16 million people on a patch of land measuring only 33,800 km2 - with more than half of it lying under sea level - must necessarily find ways to ensure both productivity and safety. The Dutch solution is a combination of hard and soft measures. Innovative delta technology offers a wide range of methods to protect against flooding. In the Netherlands, delta engineering measures are always considered in relation to spatial planning, economic development and nature development. Delta technology encompasses all forms of hydraulic engineering and water control. This integrated approach ensures the sustainability of measures. The Netherlands uses delta technology not in response to change, but in anticipation of change.
Threats and control
Dikes and dams can keep water out, but only up to a point and certainly not for ever.
Living with water is a more sustainable approach than waging a constant battle against it. The Netherlands has always tried to strike a balance between the two. The result is a form of mutually beneficial give and take. Land reclamation (for example, to provide extra space for agriculture or industry) goes together with the deliberate surrender of some areas for purposes of water retention and storage. The building of massive storm surge barriers to hold back the sea goes hand in hand with 'building with nature': using valuable natural features as the starting point for the design of delta landscapes and coastal zones.
Engineering
The Dutch have specialised in hydraulic and civil engineering. As early as the 6th century BC, settlers built artificial mounds - 'terpen' - on which to seek refuge from floods and high tides. In the 15th century, windmills were used to pump away unwanted water.
The Delta Works were constructed in the 20th century. This series of massive dams and barriers designed to protect the Dutch Delta against the sea, is famous around the world. Today, Dutch engineers are designing entire climate-proof floating cities. Whatever the challenges, the Dutch always respond by developing new techniques and technologies to manage water and use it in sustainable ways. They are born innovators.
Building barriers
Dutch expertise in the design and construction of storm surge barriers has been put to good use both at home and abroad. As recently as 2002, an inflatable dam was constructed at Ramspol: a flood barrier consisting of three huge bellows made of rubberised cloth, which fill with water and air when flooding is imminent. This provides effective protection against the rising water, does not obstruct shipping and is relatively cheap. It is the only inflatable dam of this size and operating on such a scale anywhere in the world. Because storm surge barriers offer a more flexible method of protection against flooding than dikes or dams, Dutch experts are consulted on projects around the world. Teams of consultants and engineers have been involved in the development of protective barriers in Venice, London and St. Petersburg. From carrying out feasibility studies and environmental assessments to the actual construction of water defences, the Dutch water sector covers every aspect of flood control.
New land
In densely populated areas, where space is at a premium, the construction of new land creates exciting and necessary opportunities. In many of the world's coastal areas, Dutch dredging companies are involved in broadening beaches, extending ports or industrial areas, and even creating entire new islands. Modern dredging methods are increasingly being used to fight coastal erosion. Keeping the coastline in its current position is a process of constant measuring, monitoring and planning to ensure that the right amount of sand nourishment takes place in the right places. Sand supplementation is not just a way of keeping beaches intact; it is a fundamental measure to protect land against the force of the sea. Not surprisingly, sand nourishment is increasingly being used to provide a 'soft' defensive line in several places all around the world. But why stop at maintaining the coastline? At present, the Dutch coastline has some weak spots which need to be improved in order to meet current safety requirements. At the same time, the Netherlands faces rising sea levels and heavier use of the coastline for recreational and wildlife purposes. A broader, stronger coast would provide an answer to these challenges.
As part of an innovative approach, the sandy beach could be reinforced by more substantial sand supplementations. If the extra sand is deposited in the right places offshore, the current and waves would automatically spread it along the coast in such a way a naturally balanced coastline will be created. This is regarded as a promising approach, using natural processes to create more space for wildlife and reinforce coastal defences in a sustainable, low-maintenance way. An example of what the Dutch like to call 'building with nature'.
Room for the river
A similar new approach is being used in the field of river basin management and flood control. It takes the spatial claims and natural values of the river as the starting point. In view of anticipated climate changes, it is thought likely that the rivers in the Rhine delta will have to accommodate ever-higher peak discharges. Until recently it was standard policy to maintain the required level of flood protection simply by increasing the height of the dikes. This is now seen as ineffective. The new policy is to increase the capacity of river basins by positioning dikes further away from rivers or by deepening washlands to reduce river levels at times of peak discharge. More space can also be created by enlarging the river channel within the dikes. In addition, action is being taken to prevent activities which increase peak river discharges, such as the building of houses and recreational facilities on flood plains. The aim is to strike a balance between present and future spatial requirements, seizing every opportunity both to enhance flood protection and to improve the environment. In other words, to work with, rather than against, nature.
Living in coastal regions and deltas is a risky business. The Netherlands is vulnerable not only to flooding, but also to water depletion, shortages of groundwater, subsidence, salt intrusion and pollution. A nation struggling to accommodate over 16 million people on a patch of land measuring only 33,800 km2 - with more than half of it lying under sea level - must necessarily find ways to ensure both productivity and safety. The Dutch solution is a combination of hard and soft measures. Innovative delta technology offers a wide range of methods to protect against flooding. In the Netherlands, delta engineering measures are always considered in relation to spatial planning, economic development and nature development. Delta technology encompasses all forms of hydraulic engineering and water control. This integrated approach ensures the sustainability of measures. The Netherlands uses delta technology not in response to change, but in anticipation of change.
Threats and control
Dikes and dams can keep water out, but only up to a point and certainly not for ever.
Living with water is a more sustainable approach than waging a constant battle against it. The Netherlands has always tried to strike a balance between the two. The result is a form of mutually beneficial give and take. Land reclamation (for example, to provide extra space for agriculture or industry) goes together with the deliberate surrender of some areas for purposes of water retention and storage. The building of massive storm surge barriers to hold back the sea goes hand in hand with 'building with nature': using valuable natural features as the starting point for the design of delta landscapes and coastal zones.
Engineering
The Dutch have specialised in hydraulic and civil engineering. As early as the 6th century BC, settlers built artificial mounds - 'terpen' - on which to seek refuge from floods and high tides. In the 15th century, windmills were used to pump away unwanted water.
The Delta Works were constructed in the 20th century. This series of massive dams and barriers designed to protect the Dutch Delta against the sea, is famous around the world. Today, Dutch engineers are designing entire climate-proof floating cities. Whatever the challenges, the Dutch always respond by developing new techniques and technologies to manage water and use it in sustainable ways. They are born innovators.
Building barriers
Dutch expertise in the design and construction of storm surge barriers has been put to good use both at home and abroad. As recently as 2002, an inflatable dam was constructed at Ramspol: a flood barrier consisting of three huge bellows made of rubberised cloth, which fill with water and air when flooding is imminent. This provides effective protection against the rising water, does not obstruct shipping and is relatively cheap. It is the only inflatable dam of this size and operating on such a scale anywhere in the world. Because storm surge barriers offer a more flexible method of protection against flooding than dikes or dams, Dutch experts are consulted on projects around the world. Teams of consultants and engineers have been involved in the development of protective barriers in Venice, London and St. Petersburg. From carrying out feasibility studies and environmental assessments to the actual construction of water defences, the Dutch water sector covers every aspect of flood control.
New land
In densely populated areas, where space is at a premium, the construction of new land creates exciting and necessary opportunities. In many of the world's coastal areas, Dutch dredging companies are involved in broadening beaches, extending ports or industrial areas, and even creating entire new islands. Modern dredging methods are increasingly being used to fight coastal erosion. Keeping the coastline in its current position is a process of constant measuring, monitoring and planning to ensure that the right amount of sand nourishment takes place in the right places. Sand supplementation is not just a way of keeping beaches intact; it is a fundamental measure to protect land against the force of the sea. Not surprisingly, sand nourishment is increasingly being used to provide a 'soft' defensive line in several places all around the world. But why stop at maintaining the coastline? At present, the Dutch coastline has some weak spots which need to be improved in order to meet current safety requirements. At the same time, the Netherlands faces rising sea levels and heavier use of the coastline for recreational and wildlife purposes. A broader, stronger coast would provide an answer to these challenges.
As part of an innovative approach, the sandy beach could be reinforced by more substantial sand supplementations. If the extra sand is deposited in the right places offshore, the current and waves would automatically spread it along the coast in such a way a naturally balanced coastline will be created. This is regarded as a promising approach, using natural processes to create more space for wildlife and reinforce coastal defences in a sustainable, low-maintenance way. An example of what the Dutch like to call 'building with nature'.
Room for the river
A similar new approach is being used in the field of river basin management and flood control. It takes the spatial claims and natural values of the river as the starting point. In view of anticipated climate changes, it is thought likely that the rivers in the Rhine delta will have to accommodate ever-higher peak discharges. Until recently it was standard policy to maintain the required level of flood protection simply by increasing the height of the dikes. This is now seen as ineffective. The new policy is to increase the capacity of river basins by positioning dikes further away from rivers or by deepening washlands to reduce river levels at times of peak discharge. More space can also be created by enlarging the river channel within the dikes. In addition, action is being taken to prevent activities which increase peak river discharges, such as the building of houses and recreational facilities on flood plains. The aim is to strike a balance between present and future spatial requirements, seizing every opportunity both to enhance flood protection and to improve the environment. In other words, to work with, rather than against, nature.