The realisation, planning process and planning management of green-blue urban design require a distinction between new development and existing urban locations. New development offers the possibility of starting from scratch and planning sustainable solutions. Redevelopment and revitalisation, conversely, present opportunities to work on improving the living environment step by step and project by project. Both types require specific solutions for the best possible approach and green-blue design. It is also necessary to formalise and continually incorporate the vision and measures in spatial planning procedures, to allow the plans to be put into practice. Experience shows that many good ideas and initiatives are abandoned during the planning process and the formal procedures; in short, that many opportunities are missed.
EVA-Lanxmeer in Culemborg and Delft Zuid-Oost are real-world examples of projects where working on sustainable urban development or redevelopment successfully involved all stakeholders. The EVA-Lanxmeer project concerned a new urban area. Delft Zuid-Oost involved the restructuring and improvement of an existing urban location.
Mistakes in practice
- Ambitions and plans are often too far removed from the people involved, not having been defined with the input of those people and not taking sufficient account of what is important to different people within a particular area or district.
- Insufficient administrative motivation for sustainable development. Conflicting interests often cause parties to revert to their traditional roles and seek out a sector-based approach.
- Cooperation structures for the parties concerned do not function well enough to realise high ambitions.
- Within the framework of current laws and regulations, it is complicated to integrate work and development processes for spatial planning, water and urban design.
- In the absence of a clear-cut strategy and vision for the area that have a broad basis of support, the lack of a clear focus makes it difficult to distinguish primary issues from secondary issues.
- It is difficult to calculate the added value and synergy of integrated sustainable measures.
- Separating plans and calculations for developments from management and maintenance leads to impractical choices.
General policy measures
General policy measures more or less affect all themes and are generally aimed at green-blue networks and therefore facilitating in nature.
Development of a long-term vision
The development of a long-term vision and making this vision concrete by assessing and researching the potential of a city are conditions for an efficient and successful approach. The next step is to translate and underpin this vision spatially, technically and financially into a more green-blue urban development or “green-blue grids”.
A condition for the feasibility is the assessment and research of the potential and the technical and financial feasibility of proposed measures, adjusted to urban management plans.
For the maintenance and improvement of biodiversity, but also for all other functions of urban green, such as water management, heat stress, air quality, etcetera, a first requirement is to make an inventory of, and to protect where necessary, the existing green areas and biotopes, both quantitatively and qualitatively. A strategy can be developed which ensures that these areas are expanded if possible, and connected where this makes sense. Also vacant lots, which often are nutrient-poor but rich in numbers of species and therefore highly valuable with respect to biodiversity, should not only be regarded as potential construction areas but consideration should perhaps in some cases be given to their preservation for nature and recreation purposes.
Assessment and research of the potential and the technical and financial feasibility of measures
By making an inventory of the regular maintenance and improvement activities for urban and regional water management, green planning, energy and public space in the short, medium and long term, adaptation and mitigation strategies can be developed that require little to no additional investments. In many cases, the replacement of sewers or the development of an improved, separated system can be avoided and be replaced with above-ground drainage, infiltration and buffer capacity in connection with green roofs, the reduction of impervious surface and more. These measures will also be good for biodiversity and the urban climate. Green-blue networks at the urban and regional levels which facilitate the various ecosystem services, cooling but also buffering and purifying water, biodiversity, slow traffic, recreation, the production of biomass, air quality improvement and urban agriculture, can be optimally connected to the “green grids” of the city.
Integral planning teams
Regular planning is organised by sector. When implementing adaptation and mitigation strategies and measures, it is important that the various city departments such as urban development, ecology, water management and green planning, but also citizens, project developers, environmental organisations, provincial governments and water authorities, work together on the development of new development plans and restructuring plans. Currently, they work mainly independently and consecutively on plans. By working together at an early stage, with all disciplines and all levels of scale, in working groups (climate workshops, charettes), and by aligning the different interests for instance already in the development of the long-term visions and the urban development plans, potential conflicts can be resolved and synergies can be taken advantage of. Although a more integrated form of cooperation may increase the time spent on meetings in the beginning of the process, with a clear objective, early agreements facilitate planning processes and perhaps even speed them up and improve their quality. The extra effort in the beginning will result in time savings later on.
Use of simulation models in the planning process
Several simulation models are available, such as ENVI, which make it possible – after entering data such as the percentages of impervious surface and built area, types of greenery, water areas and insulation – to assess the effects of policy measures on the air temperature. Such models exist for urban water management and temperature. These models are developing rapidly and are continuously being expanded. A disadvantage is that models have limited accuracy, but during the planning phase they can provide quantitative indications.
In certain countries there is a tax on the addition of impervious surfaces. If a building is equipped with a green roof, the tax is lower. Fiscal measures can be an effective instrument because they create awareness and work according to the “polluter pays” principle.
Inventory, retain and protect essential urban green and biotopes
Many cities in the US, but also London, Hamburg and Nijmegen, take inventory of and protect small and large green areas in the city. Based on the inventory of existing green areas, maintenance and protection strategies are developed for the short- and the long terms which are aimed at increasing, improving and connecting the amount of green area.
Establishing urban boundaries and stimulating green gardens
The Netherlands has an instrument that is exceptionally suitable for protecting undeveloped space around cities and within cities, and for keeping it green and open for a better urban climate: the spatial development plan. In practice, cities are insufficiently aware of the importance of greenery for water management, the urban climate and biodiversity. Green spaces between cities and old courtyards in cities are still being filled in.
An increase in urban density can go together with the maintenance and expansion of much more green than is customary now. Especially intensifying the development calls for the protection of existing green areas and urban gardens.
Parking underground or in layers at the edge of residential blocks leaves space for green. Stricter enforcement which would prevent inner areas from becoming completely built up is important for limiting heat stress, for water management and for biodiversity. This runs contrary to the current trend of more freedom in the interpretation of spatial development plans and in the realisation of permit-free extensions of buildings. Spatial development plans are a means for controlling land use, as is done in Zürich and in some German states, and for requiring flat roofs of new buildings to be green.
Public outreach and information
Recently, citizens in many cities have begun to demand an active role. This involvement should be supported. A good example is the information centre ‘Het Groene Hert’ in Nijmegen. This provides free information and advice in the field of sustainable housing and living, and it sells sustainable products. The centre is easily accessible in the centre of Nijmegen and has an attractive appearance.