Several strategies have been designed to assure the long-term maintenance of the project.
Referring to the documentary production, a schools’ chart of maintenance has been written and is presented to the schools before the beginning of the process. Some schools integrate students’ participation through small groups, who assure the watering and care of the bushes and other small plants. The threes maintenance is assured by the Green Department of the City.
The idea is to strengthen the care of these natural areas in the early stages, especially while the plants are settling in and gaining strength. Automatic watering systems (which consider rainfall) are also installed to avoid water stress for the plants during the summer. Complementary watering, with an educational and civic approach (with the help of local residents), is also recommended.
The goal is to have more natural and wild schoolyards, which do not require too much maintenance but allow children and other users to benefit from natural spaces in a daily and sustainable manner. It is important that children, for example, can observe the cycle of the seasons and the life cycle of plants.
Several research protocols have been implemented to facilitate the evaluation of the Oasis project, based on a logic of continuous improvement. From an environmental point of view, the notions of perceived temperature before and after the work, as well as the thermal behaviour of the installed materials, are observed in the schoolyards through sensors and laboratory analyses. The impact of the transformations on the microclimate of the schoolyards and their surrounding environment is calculated by Météo-France using numerical modelling, based on data collected by meteorological units.
Another indicator for the transformation of water courses is the biotope coefficient per surface (CBS), which makes possible to evaluate the impacts’ improvement of the new natural and artificial elements, on initially highly mineralised areas. The calculation of the CBS takes into account mineral surfaces, semi-permeable surfaces, open ground surfaces, pots, green roofs, green walls, etc.
From a social and observer point of view on new uses, the evaluation of the OASIS project is structured around three main areas: Use of the schoolyards, Co-construction of the project and knowledge and awareness of the students on climate change. The methodology is mainly organised according to a principle of ex ante / ex post comparison: comparison of the situations before and after the transformations conducted in the schoolyards.
Oasis project is in permanent evolution due to a permanent evaluation of the impacts, successes and failures in the designs. The tendency has been to create greener spaces, and to introduce new materials into the schoolyards. The first projects, in 2018, used to have infiltrating concrete floors, and nature was integrated in the design but wasn’t directly reachable to the children. Moreover, there was few transformations on topography, and few natural areas restored.
In 2019, a study trip to Brussels opened a whole new perspective for the project. As a result, there were important changes in the process of design. An integration of more natural materials was made, along with the creation of semi-private spaces for children, like tipis, huts, tunnels, and topography modifications. The asphalt ground was removed and replaced with natural materials (wood chips, straw, sand). In most of the surface areas, innovative play structures using upcycled and natural materials (labelled local woods, ancient, felled threes’ parts) were installed. New materials, more natural environment, and larger variety of elements (sandboxes, wicker huts, wooden play structures, etc.) were integrated. At the same time, the teachers now have the possibility of having outdoor courses by the creation of wooden amphitheatres in the schoolyard from logs of wood and the pedagogical gardens. New evaluations are currently being made, to measure the impacts of those new designs on children, pedagogical teams, and on environmental benefits against heatwaves for the city.