 |
 |
 |
 |
 |
 |
 |
 |
 |
  |
 |
 |
 |
 |
 |
 |
Opinion of tools
Name of the case study
Urban Green space differentiated Management
Name of tool
Differentiated Management
Opinion of tool - argumentation for choosing the tool
Here is discussed at the same time improvements gained by using the differentiated management and the tools that have allowed its implementation.
a) Environmental dimension
Water: Its preservation is ensured by a reasoned and integrated management (reduction in the frequency of watering and water quantities), by a protection of the springs and drinking water collecting areas, and by a source control of green waste production and/or pollutants emissions. The immoderate use of manure, pesticides, and weed-killers is a significant source of water pollution in urban environment. The moderate use of pesticides and the use of alternative techniques should tend to decrease this type of pollution.
Soil: The differentiated management of green space has a driving effect. It enhances the territory development and enables the urban landscape preservation.
Vegetation wastes: Those vary according to the type of vegetal structure, the quantity decreases with a minimum maintenance and with the rational use of manures. Green wastes are collected, crushed, sold and transported to a closed city (Nantes) for composting. The question of 'in-situ' storage/composting unit, to reduce transport impacts (costs and pollution), was not examined.
Biodiversity: Green space management integrates protection and increase of the biodiversity (news hedges with various layers, herbaceous edges on pond banks - see. fig. 2).
b) Economic dimension
In ten years, between 1979 and 1989, maintenance costs fell by 25% for spaces with marked horticultural vocation (class 1) and those with simple horticultural vocation (class 2) thanks to a mechanisation effort, and from 60 to 65% for the extensive green space and those of a rustic vocation (classes 4 and 5), thanks to differentiated management. The economical aspect is more noticeable for these last types (fig.1).
Figure 4: The average square meter maintenance cost per year – Tendency (source CERTU, 2001)
Personnel productivity is a relevant indicator to measure the profits released by a differentiated management compared to horticultural green space management. It passed from a ratio of 1.01 ha/employee/year (386 employees - taking all categories together - for 393 ha) in 1977 to 2.06 ha/employee/year (378 people for 780 ha) in 1997. Differentiated management proves to be a partial response to the economic problems of the cities (reduction in manpower and credits).
c) Social dimension
Taking into account social request related to park and historical gardens attendance as well as aesthetic and cultural links which make the charm of parks and gardens in the downtown area of Rennes.
- Recreation: the possibility of practising sports, recreational activities in open air, relaxation activities in green space close to one's residence (parks, gardens, public gardens, sports field, etc.), to be in permanent contact with diversified natural spaces (lawns, meadows, forests, etc.) take part in the improvement of inhabitants life.
- Education, training: the presence of nature in the city familiarizes young people with nature. School camps are organized, on site practical work via school. The children become aware of the stake, which will make them more responsible when they reach adulthood.
Some people have adopted differentiated management in their own private gardens. They increased the range of shrubs and decorative plants, "copying" the principles of design and in "imitating" vegetal compositions developed, here and there, by the city of Rennes.
d) Governance
Opinion of tool - barriers for the tool implementation
Two main barriers to a good green space differentiated management are as follows:
- The inhabitants, at least in France, remain attached to a model dominating of structured and ordered garden. This is why the installation of a differentiated management must be progressive, graduated, to proceed by small successive steps, to take into account the social context and surrounding urban fabric.
- Green space is an urban equipment of general interest. It has social, cultural, ecological, and landscape functions. Differentiated management implies a minimum of support from the inhabitants. This implies information and dialogue which have to be unceasingly renewed with residents, users, associations, teams of gardeners and local councillors.
Opinion of tool - assessment by tool users
There is a need of improvement, especially for the computer tools. This is planned, and it should take about two years to update all the data.
Users express also the need of improvement concerning public participation procedures.
Opinion of tool - reviewer\'s assessment
Green space service has become aware of their need of tools like indicators and monitoring, allowing the assessment of the green heritage sustainability. They need some help to manage the governance dimension. However they communicate a lot with other services, and they take into account their needs, which is not defined in any formal and institutional paper. It seems that the project continuity, ensured by the lastingness of the people in the services, is the key of this success.
This action does not have a strong irreversibility. Indeed the choice of implementing a differentiated management will have no irreparable effect if in the future Rennes municipality decides to change its greenspace management. It is a solution that lets future generations to make its own choice.
What tools were used to assess sustainability?
More information