Redesigning the approach to Miramas to protect against heat islands

How can we protect against urban heatwaves? How can we turn a boulevard into a pleasant setting for soft mobility solutions? How can we redesign towns and cities sustainably, by reducing their environmental impact? Our teams took up the challenge in Miramas, a town in the Provence-Alpes-Côte d'Azur region of southern France.
The mission

Protecting against heat islands

Like every city worldwide, Miramas, a small town in the Bouches-du-Rhône department (France), is experiencing more frequent and more intense summer heatwaves, which are taking their toll on the natural ecosystem and local residents.

The "urban heat island" refers to a phenomenon whereby local urban temperatures are higher than in surrounding rural areas. Caused in part by human activities, the phenomenon is set to grow in all towns and cities as a direct impact of global heating and rising population levels.

In the summer of 2018, under contract from the Ville de Miramas local authority, SUEZ Consulting and its partners began work to transform Boulevard Théodore Aubanel, on the outskirts of the town.

The new linear green space had a number of objectives:
  • To link Péronne de Miramas urban development zone (ZAC) to the town centre with a high-quality, fun space
  • To reduce soil waterproofing
  • To protect existing trees and boost urban biodiversity
  • To use resources sustainably
Our solution

Environmental issues as a key concern

Inaugurated in July 2019, the boulevard transformation project adopted measures to meet urban issues:
Climate change resilience and adaptation
  • Creation of an urban park using existing vegetation
  • Choice of draining coatings with higher albedo than traditional surfaces to reduce overheating
  • Disconnection from rainwater system and water infiltration
  • Reduction in light pollution
  • Protection of existing vegetation, particularly pine trees
Water cycle
  • De-waterproofing the road surface using a stabilised sand coating
  • Turning the former road into a green space
  • Creating longitudinal parking spaces in a combination of earth and stone covered with crushed grave
  • Creating ponds designed for direct infiltration into the water table

Circular economy and energy savings
  • Walls and street furniture made from raw earth and pebbles from the construction site
  • Lighter road surface (than traditional methods) to reduce the quantity of artificial light required to achieve the requisite level of lighting for urban streets

over

30,000
plants and trees planted
30
%
Electrical energy savings of 30%
Well-being, appeal and social cohesion among local residents
Rethinking urban landscapes to meet residents' new usage requirements:
  • A new public meeting space to enhance social cohesion
  • Soft mobility solutions encouraged through an 800m-long pedestrian and cycle path, protected from road traffic
  • A shady pedestrian promenade
  • An educational garden
  • An event space for local clubs
The results
Once the development work was complete, our engineers conducted heat assessments to determine the project's impact on urban cooling. The infrared images show surface temperatures, which give two pieces of information that are interpreted differently according to when the images are taken:
  • At night, they identify materials with high thermal inertia, which accentuate the heat island effect
  • In the daytime, they show how materials are heated by sunlight, causing thermal discomfort for users

Thermography reveals a difference in surface temperature of 10°C under equal conditions, in sunshine, between tarmac and the stabilised surface used on the new Promenade Aubanel. The difference is caused in part by:
  • The lighter surface reflecting energy rather than storing it. Albedo of 0.098 previously, compared with 0.369 now
  • De-waterproofing the promenade and fountains causes evapotranspiration of plants, cooling the surrounding air
  • Shade provided by century-old trees and pergolas
Pavement in the sunshine on Avenue Jean Mermoz (conditions similar to those on Boulevard Aubanel's pavement before completion of the work)
Stabilised surface in the sunshine on Promenade Aubanel, after completion of the work
Contact
Logo SUEZ

Gilles Tourbillon

Urban Infrastructure Activity Director, Southern France and Overseas Division, SUEZ Consulting [email protected]