About this issue

Volume 40 – Number 2
302 pages


This issue is dedicated to ‘Delta urbanism’, addressing the need to find special approaches and solutions for spatial planning and urban design in delta regions. The series of recent floods in urbanized delta areas shows the need for a fundamental reconsideration of urban development in delta, coastal and river plain areas.

Delta-Urbanism: New Challenges for Planning and Design in Urbanized Deltas

This issue of Built Environment is dedicated to ‘Delta urbanism’, addressing the need to find special approaches and solutions for spatial planning and urban design in delta regions. The series of recent floods in urbanized delta areas (New Orleans 2005, Japan 2011, Bangkok 2011, New York 2012, etc.) shows the need for a fundamental reconsideration of urban development in delta, coastal and river plain areas. However, with ‘delta urbanism’ we do not mean that we should focus only on the effects of climate change and on the question of improving flood defence systems.

Deltas and coastal areas are the most urbanized and urbanizing areas worldwide; some of the world’s largest metropolises are in delta areas. Climate change, resulting in sea-level rises, larger peak discharges of rivers and increasing intensity of rainstorms will certainly have a major impact on these metropolitan areas. But climate change is not something which started recently, and it is not the only change which takes place in the urbanized world. A previous issue of Built Environment focused attention on climate change as a ‘new determinant of spatial planning’ (Priemus and Rietveld, 2009). This present issue will focus on the relations of this new determinant with other developments in urbanized deltas and tries to identify new challenges for spatial planning and urban design.

The recent and current attention to climate change and the possible impact on urbanized areas coincides with fundamental changes in urbanization and land-use patterns generally. In short, we will discuss the most important of these changes.

Land-Use Changes

Today delta regions cross the world are confronted with substantial land-use changes. A first change, related to globalization and technological progress, concerns the ports and port-related industries, which became a dominating factor in the economic and spatial development of many delta areas. Modern port and transport logistics created the need to reconsider the position and construction of these ports. De Langen (2003) and Wang et al. (2007) showed the importance of the rise of regional seaport-clusters. Until recently, many large deltas each had several seaports, which used to compete with each other. Modernization and globalization of supply chains resulted in these ports developing regional coordination and collaboration of such activities as transhipment, storage, processing and distribution of goods. The development of these new regional seaport clusters not only addresses the need for new specializations in the different ports but also the need for new interconnecting infrastructures among the ports of a regional cluster. A recent study of the Flemish-Dutch Delta (Vanelslander et al., 2011) emphasizes that the port of the future will be a continuously innovating port, dependent on and collaborating with advanced knowledge institutions. In order to be attractive to the knowledge economy, authorities in deltas should pay attention to the quality of the natural environment. The presence of interesting natural environments with wetlands and beaches and with facilities for swimming, sailing, fishing, tracking and biking, is an important trump card of regional port clusters for the future.

The processes of modernization and reorganization of ports are accompanied by new urban developments in former port and dockland areas. A great deal of academic research has been devoted to this development over the last twenty-five years or so (for instance Hoyle et al., 1988; Meyer, 1999; Desfor et al., 2011). It has become clear that the urbanization of waterfronts leads not only to an extension of the urban territory, but also to changes in the spatial and functional structures of the cities. The new waterfront developments play an important role in branding strategies designed to change the dominant image of the industrial port city to a post-industrial creative and knowledge city.

A third change regards the energy-transition, which is (or can be) related directly with the previous two mentioned changes. Many large ports are hubs of transport, processing and distribution of fossil fuels. A real energy transition might have serious consequences for the role and position of these ports. Delta regions might change their role from distribution centres of fossil fuels to production centres of new types of energy, using the natural dynamics of the delta: wind, sun, tidal energy and currents.

The fourth change concerns food production, both agriculture and fishing. The alluvial soils of delta areas are the most fertile of the world, and the delta waters are the nurseries of many species of fish and shellfish. Considered in the perspective of the world food problem, delta areas can and should play a crucial role. In the processes of spatial development in such areas, agriculture and fishing seem to be competing with urbanization, industrialization and even with nature conservation. It is important to find new approaches to agriculture in deltas, which can be combined with repair of estuarine nature. Research-experiments in this field are encouraging (Stuyt et al., 2006).


Building with Nature

Since the 1960s, environmentalists, nature organizations and landscape architects like Ian McHarg (1969) have emphasized the unique and precious, but also vulnerable qualities of deltas and estuaries in the worldwide ecosystems of rivers and oceans. The study by Costanza et al. (1997) of the economic value of ecosystems is scientific confirmation of the importance of deltas and estuaries. Meanwhile, organizations like the World Wildlife Fund, America’s Wetlands and the Wetland Foundation are considered important players in many deltas worldwide. The need to protect the biodiversity and especially the species which are dependent from the specific delta conditions (land-water gradients, salt-fresh water gradients) is not the only reason for paying attention to the natural environment. During the nineteenth and twentieth centuries, deltas, especially in the Western world, became victims of serious erosion and decay, caused by transformation of these natural systems into man-made, engineered systems. Human interventions in the river and delta systems, such as damming and channelization, caused a substantial decrease in the transport of sediment by the rivers to the deltas. Moreover, drainage resulted in land subsidence in many delta regions. Together these processes have led to serious erosion of many urbanized deltas (Saeijs, 2006; van der Meulen et al., 2007; Mulder et al., 2009). The Nile delta is an extreme example, but also the Dutch delta and the Mississippi river delta are suffering from this. The question is to what extent sediment supply and the water retention and absorption capacity of delta areas can be restored, by repairing the natural system and/or introducing artificial methods of sediment supply and new drainage technologies. ‘Building with Nature’ and ‘Working with Water’ have become new slogans in delta technology during the last decade, for instance in the report of the Dutch Delta Committee (Deltacommissie, 2008).

These slogans express a new approach to hydraulic and coastal engineering, with new collaborations between ‘traditional’ civil engineers and specialists with a more ecology or landscape oriented background.


Changes in Delta Management

Finally, how can these changes be managed and combined with new flood defence strategies? This question touches perhaps the most important change in delta areas. The two nations with the greatest expenditure on flood control systems in the twentieth century were the United States and the Netherlands (O’Neill, 2006). In both countries, their flood control systems were built by strong and centralized state-institutions: the US Army Corps of Engineers and the Dutch Rijkswaterstaat. In the Netherlands, flood control policy was combined with central government policy related to industrialization and urbanization of the delta (Meyer, 2009). This approach no longer fits the reality of local and regional communities and other stakeholders in the deltas of the twenty-first century. This is not just about ‘top-down’ versus ‘bottom-up’, but also about the roles and responsibilities of public authorities, private institutions and individual citizens. The Dutch delta might be considered as a benchmark of sophisticated delta management in the twentieth century. It was based on avoiding risks as much as possible, with the state having the monopoly in organizing this risk-avoiding policy. This approach ended up on a slippery slope from the end of the twentieth century, because of the increasing complexity of organizing this policy and because of an erosion of the role of the state. New concepts have been introduced such as the ‘multi-layer safety’ approach, which involves, in addition to building appropriate flood defences, more attention being given to the possibility of flooding and to evacuation. It also means moving responsibilities from central government to local authorities, private institutions and citizens (Ministry of Infrastructure and the Environment, 2009).

This issue of Built Environment addresses the increasing complexity (and the increasing awareness of this complexity by scientists, planners, designers and politicians) of urbanized deltas, resulting in a paradigm change regarding management and spatial planning in urban deltas. The question is pressing forward if more integrated and comprehensive approaches of planning and design in the delta are possible. The key issue is no longer to solve the ‘problem’ of climate change but to derive new strategies to save delta regions from erosion, subsidence and disastrous flooding; strategies that can also play a role in creating and supporting processes of changing land-use, as mentioned above, in desirable directions.


An Outline of the Issue

This issue comprises three sections. The first has an introductory character and starts with an exploration of the complexity of delta regions. Ed Dammers, Arnold Bregt, Jurian Edelenbos, Han Meyer and Bonno Pel argue that it makes sense to consider delta regions as complex systems and to make use of the insights of theories of complex systems. This delivers not only new theoretical perspectives on the spatial development of delta regions, but also new perspectives for the practice of spatial planning, design and governance. This article is a result of research by a consortium of Dutch universities, consultancy firms and research institutions, which tried to develop new perspectives for planning and design in the Dutch Southwest delta. This region became world famous because of the Delta Works, built in the second half of the twentieth century and an extreme example of top-down planning. While this type of planning has become impossible under the current societal conditions, interventions in the region are necessary in order to adapt the region to climate change and to changing economic, demographic and environmental conditions. The article ends with some suggestions for a new practice of planning, design and hydraulic engineering in this region.

The second contribution to the introductory section by Luuk Boelens focuses on the issue of the governance of delta regions. Boelens argues that ‘delta metropolitan regions’ worldwide are characterized by a history of self-organization, strongly related to the physical fragmentation of the delta territory. This history distinguishes delta regions fundamentally from ‘capital metropolitan areas’, which are characterized by a history of strongly centralized political power. Boelens underpins his theory with two different case studies: the Northwest European ‘Eurodelta’ of the rivers Rhine, Meuse and Scheldt, and the Asian Pearl River delta. Both delta regions have been confronted with attempts by strong central governments to get the region under control. However Boelens claims that the forces of self-organization in these regions are much stronger in the long term. Spatial planning in these delta regions should depart from the awareness of this tradition of self-organization.

The second section focuses on the interaction between the physical development of the delta region, the use and technical treatment by humans and the management of the delta region. In many delta regions this interaction has resulted in severe erosion, an increase in people’s exposure to hazards and serious decay of natural eco-systems. The need to develop an alternative approach is explained in the article on the Mississippi River delta and the Senegal River deltas by Richard Campanella. By describing the historic evolution of these delta regions, and especially of the management and technical interventions in there, he shows that both deltas have reached a point of a critical dilemma. Both delta regions find themselves at a crossroads of different approaches. One direction is the continuation of the policies and interventions as developed during the last century, which will lead to an acceleration of the erosion of the deltas and to an increase in their citizens’ exposure to hazards. The other direction will be a radically different approach, which means different types of technical treatment of the delta, different types of land use, and especially a different type of management and governance of the delta. The last will be the most difficult but, in the long term, the only one which creates perspectives for sustainable urban development.

The next three articles in this section build on this need for a new approach and focus on three different delta regions, which find themselves in different stages of physical growth or erosion.
Cornelia Redeker and Sameh A. Kantoush describe the disastrous situation of the Nile delta, which finds itself in an extremely vulnerable situation because of the building of large dams upstream. The lack of fresh water supply results in an increase of saltwater intrusion, while the lack of sediment disposal leads to land subsidence below mean sea level. The region is threatened both by flooding and by desertification. The Nile delta already suffers a daily land-loss of 34 hectares, and this is expected to increase in the future. The authors plead for more attention to grassroots initiatives, which might if not stop then at least slow down this dramatic process of land loss.

The Parana delta in Argentine, as described by Veronica Zagare, is an example of an opposite development. Because of the ongoing process of transport and disposal of enormous amounts of sediment (derived from the Andes), the land in this delta is still growing. The natural process of land creation means that the edge of the delta area is moving with a speed of between 500 metres to 1 kilometre a year. Several attempts have been made to cultivate the new land in the past, but without much success. Most of the delta territory still looks like a wilderness. Today, the growth of the delta area is a reason for two types of human intervention: one is the building of new urban settlements. While the metropolitan region of Buenos Aires has become very crowded, the new delta area provides opportunities for new urban development – both gated communities and shantytowns. Uncontrolled progress of this development will create problems for the discharge of water and result in serious floods. The second type of human intervention is the dredging of the main channels of the river in order to maintain the accessibility of the upstream seaports; the port of Buenos Aires is threatened by silting up, which is a reason for intensified dredging. These dredging activities lead to an increase in the vulnerability of the hinterland to storms and flooding from the sea. A fundamental reconsideration of policies concerning port development and shipping, urbanization and flood control will be necessary to prevent serious disasters in the future.

The fourth contribution in this section by Marcel Marchand, Pham Quang Dieu and Trang Le describes the difficult dilemma in which the Mekong delta finds itself. Because of an ingenious system of canals, constructed during French colonialism in the nineteenth century and related with the specific agriculture of rice growing, large parts of this delta territory are frequently flooded in a controlled way. The result is a coincidence of intense land use and continuous supply of fresh water and new sediment deposits. It means that the land rises with the same speed as the sea level. However this system is threatened by dam constructions upstream and by industrialization in the delta region itself. The question is whether this delta region will take the same path as many Western delta regions in the nineteenth and twentieth century, resulting in a future comparable with the eroding deltas of Nile, Mississippi and Rhine, or will the region be able to continue its unique way of natural land elevation?

The third section focuses on the specific patterns of land use in delta regions and on the meaning of design. The article by Peter Bosselmann and Sarah Moos explains the urban patterns as developed in the San Francisco Bay Area and the Pearl River Delta. Both delta regions show a strong tradition of developing urban patterns, which were able to deal with the specific conditions of the delta. While both regions have been confronted with explosive urban growth recently, the question is what lessons can be learned from this tradition which are relevant for today’s and tomorrow’s urban development. Bosselmann and Moos organized design projects with American and Chinese students in order to test some concepts, based upon historic typologies of delta cities.

Nikki Brand, Inge Kersten, Remon Pot and Maike Warmerdam were involved in a research by a consortium which investigated the possibility of using the need to enforce the Dutch coastline as a means of improving the spatial quality and accessibility of the coast. The Randstad Holland, with 6.5 million people, has a unique possibility to enhance the quality of its coastline. The use of this coast is not very intensive, mainly because the accessibility as well as the quality of most seaside resorts is rather poor. A consortium of the Dutch Delta programme, Delft University, public authorities and a dredging company investigated the possibilities of combining the task of strengthening the flood defence with a substantial improvement in the spatial quality of the Dutch coast. A process of research by design, organized in a series of workshops with experts and local stakeholders, resulted in a new vision on the coast, which will be adopted by the new Dutch delta programme.

While the second section starts with the contribution of Campanella on the Mississippi river delta, the third section ends also with the same delta region. The article by David Waggonner, Nanco Dolman, Derek Hoeferlin, Han Meyer, Pieter Schengenga, Sabien Thomaesz, Jaap van den Bout, Jaap van der Salm and Chris van der Zwet can be considered as an answer to the plea from Richard Campanella to look for another approach of the physical development of the delta. The authors participated in a large American-Dutch consortium responsible for the making the ‘Greater New Orleans Urban Water Plan’, which aims to guide the Greater New Orleans metropolitan region to become ‘America’s Water City’. New Orleans already had major problems before the Katrina disaster of 2005, suffering from an economic downturn, increasing poverty and a shrinking population. Just repairing the flood defence system will not change this situation. Also in this case, design played an important role as part of a method, which combines improving water management with improving spatial quality, resulting in new economic and social perspectives. This is necessary in many urbanized delta regions. The authors claim that the process of the New Orleans plan has resulted in a method, which is also relevant for other delta cities.



The articles in this issue address a number of topics concerning urbanized deltas and climate change, which leads to the following conclusions.
First, the threats and vulnerability of flooding are not the result of climate change, but mainly of the way humans deal with the physical conditions of rivers and deltas. The decay and erosion of many delta areas, caused by human intervention, should be stopped. A fundamentally different approach is necessary.

Second, the attention to new flood defence and water management approaches should be combined and integrated with new spatial, economic and social issues. Many delta cities do not suffer only from flooding, but also from economic and social problems and poor spatial quality. The need for investment in new water management systems provides a unique opportunity to combine different goals with these investments.
Third, design can play a powerful role as part of a research method, aiming to discover new possibilities for combinations of new types of flood defence, water management and new spatial and functional features. Urbanized delta regions might become the most interesting testing laboratories to develop methods with new balances of science, engineering and design.



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