II.4.1. Exposure reduction measures

Good practices that are already in use on the territory of Plaine Commune are the installation of fountains, introduction of new green areas, landscape design with natural water infiltration rather than rainwater sewage, light-colored street cover (Fig.34 ).

To further decrease urban heat island effect and thus, help decrease some of the negative effects of heat waves, to raise outdoor comfort during hot days, there are several possible strategies.

The measures proposed in EPICEA project, which studied the effects if climate change in Paris region, include introduction of more green areas, watering the streets and changing the reflective properties of buildings and streets surfaces. The results of the EPICEA project show that the strategy of introduction of vegetation in the city is more efficient compared to other adaptation methods aimed at decreasing urban temperature, yet this method is only efficient if green zones are regularly watered. If sufficiently watered, green zones may help reduce the temperature by 1-3 ° C during a heat wave while the temperatures in French capital agglomeration are projected to rise by 3,5 to 5  ° C by the end of the century. (CSTB, la Ville de Paris, Météo-France, 2012)

34a 34b34c

Fig.34 a) Fountains, Place René Clair, Epinay-sur-Seine; b) landscape design, favoring stormwater infiltration, Quartier des 4000 Nord, La Courneuve; c) shaded area near Hôpital Casanova, Saint-Denis.

 The measures proposed in EPICEA project, which studied the effects if climate change in Paris region, include introduction of more green areas, watering the streets and changing the reflective properties of buildings and streets surfaces. The results of the EPICEA project show that the strategy of introduction of vegetation in the city is more efficient compared to other adaptation methods aimed at decreasing urban temperature, yet this method is only efficient if green zones are regularly watered. If sufficiently watered, green zones may help reduce the temperature by 1-3 ° C during a heat wave while the temperatures in French capital agglomeration are projected to rise by 3,5 to 5  ° C by the end of the century. (CSTB, la Ville de Paris, Météo-France, 2012)

The territory of Plaine Commune enjoys significant natural heritage: 115 parks and squares are located on the territory, including outstanding parks like park of l’Île-Saint-Denis (23 ha) and La Courneuve (415 ha). But more medium size green space as well as introduction of vegetation on the streets to create shade for pedestrians and mask buildings’ walls is needed to significantly decrease the rising temperature. These measures are introduced in the new territory development agreement (CDT) (Fig. 35)

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Fig.35. Plan for development of green space in Plaine Commune Source: CDT 2014-2030

Urbanization deprives cities of natural thermal regulators: water and vegetation, in exchange for cleaner environment with its stone, or asphalt, or concrete coverage of streets, attracting and retaining heat. Water and Sanitation Department of Seine-Saint-Denis has launched a feasibility study of reopening the streams which now are directed to sewer (la Vieille Mer, ru Montfort, ru du Rouillon, ru d’Arras) and a study of alternative techniques of managing surface stormwater in the zones of redevelopment projects (ZAC Tartres, Docks of St Ouen, L’Île-Saint-Denis), these measures might prove beneficial to refresh the environment and support natural vegetation and thus diminish heat island effect.

To decrease health risks related to outdoor exposition to heat, the most busy pedestrian zones should be identified (public transport stations, pedestrian streets, streets in business districts, entrance zones near concert halls, amusement parks, stadiums, etc[1] (Fig. 36)) and measures should be taken to protect them at least from direct sunlight in order to ensure comfort for pedestrians. For these purposes, planting trees or installation of temporal awnings above pedestrian streets and the most attended places is good way of protecting people from the discomfort and overheating.

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Fig.36 Coldplay fans waiting for the concert near Stade de France, Saint-Denis. Photo by Chris K., retrieved from: http://coldplayer.fr/2012/09/review-du-concert-paris-stade-de-france-by-chriis/

Dense urban territory, Plaine Commune is very vulnerable to the phenomenon of urban heat island effect, especially in the context of today’s and future climate change.

Planned and implemented actions nevertheless contribute to reduce this sensitivity by enhancing vegetated areas and storm water management operations.

The following should be considered as further adaptation measures to be introduced on the territory:

– Considering heat island effect in planning and urban renewal activities (construction materials, vegetation, shading, urban form, storm water management);

– Reduction of potential social tensions related to access to water and cool spaces through better design of public space.

[1] The author of the photo in his review of the concert mentions that he arrived several hours before the start of the concert in order to be sure that he will get a place closer to the stage. Such behavior is not unusual for fans. The area around Stade de France is left open (for safety reasons), there are not many shaded areas to escape summer heat.

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