Climate-adapted design for surface water solutions

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Products/Technical solution, Technologies and Building systems

DESCRIPTION:

The school courtyard was redesigned as a park with varied vegetation heights and a combination of permeable and natural surfaces, covering at least 30% of the outdoor area. The design supports local surface water management by retaining and infiltrating rainwater on site, in line with the City of Oslo’s approach to reducing runoff impacts on buildings, infrastructure, and surrounding areas.

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Target Users

Architects, Constructors, Local authorities, Material providers, Policy makers and regulating authorities, Research community

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Oslo, Norway

Nordic

Sustainable Building (Re)Design

VALUE

The City of Oslo’s work on stormwater management is a critical initiative for the city to become climate resilient. Numerous measures have been implemented since the Stormwater Management Action Plan was considered at political level in 2019. Oslo’s property enterprise promotes the use of open, local surface water management on municipal land to contrast the damage to buildings and infrastructure produced by poor rainwater management. Such a problem is exacerbated by climate change, which in the Nordics will lead to more rain and sudden heavy rainfall. By opening closed streams and rivers and using green roofs and draining surfaces instead of asphalt, rainwater flows are slowed down and the risk of flooding reduced. The demonstration of this innovation in the Voldsløkka project aims at showing how technological solutions for effective local storm water management can be designed and implemented by integrating educational purposes and without sacrificing the aesthetic of a natural environment within city borders.

APPLICATION

The stormwater management system implemented at the Voldsløkka school has been fully operational since August 2023 and serves as a demonstration of both performance and technical limitations, including material durability, vegetation growth and health, and long-term drainage efficiency, with a view to replication in other contexts. The school’s green areas are organised into two main landscape typologies: vegetated zones along the site edges and central green islands. The central areas consist of planted islands surrounded by channels that guide rainwater across the site. Terrain gradients direct runoff towards these channels, which are covered by metal grates and incorporate rain beds planted with Norwegian wild perennial meadow species. Stormwater is collected in the channels and conveyed to the islands, where it infiltrates through the vegetation and into a crushed stone reservoir below. The island–channel system is deliberately designed to make water flows visible and to clearly demonstrate the stormwater management principles applied on site.