Medium_optimized-wp_20160303_002 Dublin City Council Green Roof Author Dara O Daly (Landscape Architect DCC)

09 May 12:56

Roisin Byrne

Dublin City Council leading in Small Steps in Green Infrastructure.

Green Roof Lower image by Dara O Daly, DCC Parks & Landscaping Services

A shift away from a car dominated street scape created opportunities for Dublin City Council to undertake several new green projects. The site for these projects is situated in Dublin city centre adjacent to several heavily trafficked carriageways.
Areas of flat roof were converted to wild flower meadows as part of a broader project to improve the soft landscaped areas around the Civic Offices in Dublin City Council. The broader project seeks to address several issues including poor pedestrian access, anti-social behaviour and a haphazard planting scheme. The green roof area of the project consisted of two pavilions which form part of the access to the underground carparking. Both of these strucutures already featured green roofs. However, they were not considered biodiverse or visually beneficial to the local environment. One roof in particular is quite accessible due to changes in level, about 1.3m above ground level and it was originally planted with Lonicera pilieata and other heavy evergreen shrubs. This has been a destination for drug users in the past.
Green roof as view from Planning Department Floor
The last decade has seen a greater emphasis placed on the importance of green technologies and nature, particularly in the urban environment. As a landscape architect and someone who is passionate about the environment the benefits of greening our cities have always been obvious. It is also encouraging to see engineers and architects beginning to embrace theses concepts. On a more cynical note, it sometimes seems that these important concepts are being exploited to market new residential and commercial premises. Green roofs have their place as part of a broader picture in greening our cities. In a lot of situations it is about utilising the right feature. This may be the planting of a new tree, the replacement of an expanse of concrete with a planted bed or the installation of a green roof.
In the case of the wild flower meadows installed on the two green roofs it was a straight forward installation. The pavilions feature considerable reinforced cast in situ concrete roofs and a generous depth of existing topsoil. The installation of the green roofs was a straight forward process which included the removal of existing vegetation, and the stripping of topsoil. Bulbs were placed out and the wild flower turf laid.
Green wall projects consisting of extensive irrigation, drainage and structural support systems supporting planting. In this situation it is hard to see how a well chosen climbing plant could not fulfil the same role.
Greening our cities has an exhaustive list of benefits to many facets of life. These include positive benefits for human health and society, the economy and the creation of a resilient city. Going forward, the concept of a resilient city is becoming more relevant and important. The extremes of weather being experienced in Ireland manifest in heavier periods of rainfall, increased wind intensity and extended dry periods in the Summer months. Flooding has been particularly destructive this Winter.
The Dublin City Council green project installations had an immediate impact on the anti-social behaviour. The area is no longer used for drug use as the removal of the shrubs has eliminated a hiding spot. At present, an academic study is being organised that will record and examine the change in local insect life.
Bug hotels are being constructed which will be located on the taller more inaccessible wild flower roof. These have been designed by a consultant and constructed in collaboration with a local primary school. The frames for the bug hotels will be constructed from recycled pallet timbers and infilled with clusters of bamboo and branch sections.
Although small steps, these installations are an important step for Dublin in the recognition of the multiple benefits of green infrastructure.
Micro view from Green Roof Garden. image by Dara O Daly DCC Parks & Landscaping Services

Keywords: Urban Green Roofs, Green Projects, Act local,