Jardí Illa

El Eixample is the district with the highest levels of air and noise pollution in the city, with the worst deficit of green spaces. The application of the Superilles concept model in the Eixample involves a global reorganization of mobility that allows freeing up 1 in every 3 streets from through traffic to convert them into new green axes. A new network of 21 axes and 21 squares can thus be created, acting as an environmental and social infrastructure, improving comfort and health conditions, and increasing the presence of greenery and stay spaces in a systemic and balanced manner throughout the area.

During the period 2020-2023, a first phase has been developed and executed, which includes sections of 4 streets, as well as 4 squares at their intersections and at the intersection with Enric Granados Street. This first phase has involved the transformation of a total area of 110,000 m², with 4.65 km of green axes and 8,000 m² of squares. The space for pedestrians has increased by 58,000 m², the permeable surface has gone from 1% to 15%, urban greenery has been expanded with 11,000 m² of new plants, and 400 new trees have been planted. The increase in shaded areas and the replacement of asphalt have allowed for a 5 °C reduction in surface temperature during the summer.

The intersection of Consell de Cent and Enric Granados streets has special characteristics that set it apart from the typical intersection in the Eixample of Barcelona. The first is the fact that it is located at the midpoint of a botanical route that connects Plaza Letamendi, with its imposing Washingtonia palms, to the gardens of the historic building of the University of Barcelona. These gardens have great botanical interest and feature more than 150 plant species, housing some of the oldest trees in the city. The second distinguishing feature is the cultural and heritage value of the two key architectural ensembles in the image of Barcelona and the Eixample: the Conciliar Seminary and the historic building of the University of Barcelona. The proposal seeks to enhance the botanical and architectural heritage by integrating vegetation and species that improve the existing canopy and plant heritage. A garden is planned where there used to be an intersection, returning the space to the people, so that the new square is characterized by an explosion of greenery, brought to every possible corner of the square.

The design of the greenery has taken into account the extent of the existing plant canopy, analyzing those cases in which its phytosanitary condition makes replacement more advisable. The other premise has been to expand the existing greenery by planting new tree, herbaceous, and shrub specimens. The species have been selected considering: the current and future climate due to the effects of climate change, their functionality in the urban context, as a garden for everyone, and according to the available soil, prioritizing in all cases the enrichment of the area's biodiversity.

Under the premise of making the garden and the species readable, it is essential that their planting demonstrates the passage of the seasons. The growth and disappearance of the vegetation, therefore, becomes a project element. Among the chosen species, many herbaceous plants disappear during the winter, giving way to a different image of the garden than in spring or summer, when most of the flowers bloom. In this aspect, the garden aims to be an element that embraces the different seasons, with species that bloom at various times and never as a final image, but as a constant construction of the landscape.

There are times when shrubs play a main role, and at other times, herbaceous plants occupy the city's imagination. A relationship has been established between deciduous and perennial vegetation, so that even if some species disappear during a season, the garden maintains its structure.

The first of the proposed gardens is the botanical garden, which addresses a major issue such as the global loss of biodiversity and focuses on introducing species that have a synergy with insects and small invertebrates to improve and facilitate their relationship with greenery. Additionally, seeking to reinforce the role of the botanical garden as a biodiversity refuge, an insect hotel is incorporated as a wildlife attraction.In the interior part of Jardí Illa, a low-maintenance Mediterranean-type vegetation space is proposed, recovering the richness of the native flora of the city's climate. The flowerbed represents a small reserve of local flora, very resilient and requiring little to no maintenance. The Mediterranean garden recreates the natural habitat for many native species and insects and reinforces their role in the ecosystem. In this case, shrub species stand out, such as the tree heath, which attracts hymenopterans, or others like sage, a very aromatic and low-maintenance shrub, or santolina rosmarinifolia, which attracts butterflies.

Finally, the rain garden captures runoff and rainwater to return it to the aquifer. Species typical of gardens associated with wetland areas are arranged, in response to the need to relieve the existing networks and to recover the subsoil, also establishing a pilot test for filtering water coming from the city's soil. This garden is located in the outer parts of the square, with sufficient sunlight for semi-shade species. The different types of SUDS used in the project are: tree pits, bioretention strips, floodable flower beds, and infiltration basins.