Fukuoka, Japan
City population: 1539000
Duration: 1990 – 1995
Implementation status: Completed
Scale: Sub-microscale: Street scale (including buildings)
Project area: 5400 m2
Type of area: Public Greenspace Area
Last updated: October 2021

The 'Step Garden' is a 14-tier green roof atop the Asian Cross Roads Over the Sea (ACROS) Fukuoka Prefectural International Hall in Fukuoka, Japan (Ref. 2). The Hall itself is a centre of international, cultural and information exchange, and sits amidst the Tenjin Central Park (Ref. 3). As the building displaced a plaza, the architect, Emilio Ambasz, created the “image of a mountain" through the design and installation of the roof terrace (Ref. 2), "want[ing] to give back to Fukuoka’s citizens all the land the building would subtract from the city" (Ref. 3). In combination with the Central Park, the rooftop garden is considered to be the only open green space in the city centre (Ref. 4), and since its inauguration in 1995, has been open to the public, accessible via two entrances on the park side of the building (Ref. 1).

ACROS Fukuoka Prefectural International Hall in 2017
ACROS Fukuoka Prefectural International Hall in 2017
https://www.acros.or.jp/english/floor/stepgarden.html#

Overview

Nature-based solution

  • Nature on buildings
  • Green roofs
  • Parks and urban forests
  • Large urban parks or forests
  • Blue infrastructure
  • Lakes/ponds

Key challenges

  • Climate action for adaptation, resilience and mitigation (SDG 13)
  • Climate change adaptation
  • Water management (SDG 6)
  • Stormwater and rainfall management and storage
  • Green space, habitats and biodiversity (SDG 15)
  • Habitat and biodiversity conservation
  • Green space creation and/or management
  • Regeneration, land-use and urban development
  • Promotion of naturalistic urban landscape design
  • Health and well-being (SDG 3)
  • Creation of opportunities for relaxation and recreation

Focus

Creation of new green areas

Project objectives

In developing the site, the architect wanted to "the maximum extent possible...to give back to Fukuoka’s citizens all the land the building would subtract from the city" (Ref. 4). The architect was awarded the project due to their "successfully achieving reconciliation between...two opposing desires: doubling the size of the park while providing the city of Fukuoka with a powerful symbolic structure at its center" (Ref. 3). Similarly, the design was considered to satisfy the need to compromise between "the developer’s desire for a profitable site and the public’s demand for green space" (Ref. 5). Although construction of the ACROS Fukuoka Prefectural Hall saw the initial loss of publicly accessible green space, the continued provision of greenspace at the culmination of the construction process was of utmost priority to the project (Ref. 3). Continued support of biodiversity within the area was pursued through the inclusion of local plant species into the roof garden (Refs. 1 & 2). It is unclear whether climate change adaptation was specifically considered during the planning of the project in 1990, although such benefits have been recorded since the completion of the project, as recorded below.

Implementation activities

The inclusion of the green roof into the building design affords the following attributes which help realise the objectives and targets: - "Each terrace floor contains an array of gardens for meditation, relaxation, and escape from the congestion of the city, while the top terrace becomes a grand belvedere, providing an incomparable view of the bay of Fukuoka and the surrounding mountains" (Ref. 3); - "A stepped series of reflecting pools upon the terraces are connected by upwardly spraying jets of water, to create a ladder-like climbing waterfall to mask the ambient noise of the city beyond" (Ref. 3); - "The plan for Fukuoka...creat[es] an innovative agro-urban model" (Ref. 3), with Ref. 3 further summarising the architect behind the project, "ACROS stands as a demonstration that “the dominant concept according to which ‘cities are for buildings and suburbs are for parks’ is wrong. It is too easy to relegate nature to the suburbs and leave greyness in the city. It is an idea that completely lacks imagination.” ~ Emilio Ambasz"" (Ref. 3); - "After construction, 76 varieties total[l]ing 37,000 plants were planted. Subsequent additional planting and the dispersal of seeds by wild birds have served to bring even greater diversity to the garden, which currently boasts 120 different varieties and a total of 50,000 plants" (Ref. 1);

Climate-focused activities

Climate change adaptation:

  • Increase or improve urban vegetation cover to help reduce outdoor temperature
  • Create or improve outdoor spaces to help people escape from urban heat

Biodiversity conservation or restoration-focused activities

Biodiversity conservation:

  • Protect and enhance urban habitats
  • Create new habitats

Main beneficiaries

  • Local government/Municipality
  • Public sector institution (e.g. school or hospital)
  • Citizens or community groups

Governance

Management set-up

  • Co-governance with government and non-government actors

Type of initiating organisation

  • Private sector/corporate actor/company

Participatory approaches/ community involvement

  • Other
  • Unknown

Details on the roles of the organisations involved in the project

Development of the building on which the NBS is situated was initiated by the prefectural government (Ref. 6). In need of a new governmental building, the city "chose to develop the site in joint venture with private enterprise" whereby "a commercial developer would lease the land for sixty years and construct a building" (Refs. 3 & 6). Awarded the commission, the architect Emilio Ambasz in combination with Nihon Sekkei, Takenaka Corporation, Plantago Corporation and Katamura Tekko Company designed and developed the building into which the NBS rooftop was integrated (Ref. 3). Following building culmination in 1995, the ACROS Fakuoka Foundation "manages and administers the public sections of the ACROS Fukuoka building (approximately 40% of the total building) on behalf of Fukuoka Prefecture" (Ref. 7).

Project implemented in response to ...

... an EU policy or strategy? No
... a national policy or strategy? No
... a local policy or strategy? No

Financing

Total cost

€2,000,000 - €4,000,000

Source(s) of funding

  • Public regional budget
  • Insurance firms

Type of funding

  • Unknown

Non-financial contribution

No

Impacts and Monitoring

Environmental impacts

  • Climate, energy and emissions
  • Lowered local temperature
  • Environmental quality
  • Improved air quality
  • Reduced noise exposure
  • Water management and blue areas
  • Improved stormwater management
  • Green space and habitat
  • Promotion of naturalistic styles of landscape design for urban development
  • Increased green space area
  • Reduced biodiversity loss
  • Increased number of species present

Economic impacts

  • Unknown

Socio-cultural impacts

  • Social justice and cohesion
  • Improved access to urban green space
  • Health and wellbeing
  • Improved mental health

Type of reported impacts

Achieved impacts

Presence of formal monitoring system

Unknown

Presence of indicators used in reporting

Yes

Presence of monitoring/ evaluation reports

No evidence in public records

Availability of a web-based monitoring tool

No

References

1. ACROS Fukuoka Foundation (n.d.). Facility Guide: Step Garden. Fukuoka: ACROS Fukuoka Foundation. Source link [accessed 10/09/21];
2. Eidt, J (2014). Landscape Urbanism: Green Roofs, Community Farms in Japan. Los Angeles, California: WilderUtopia. Source link [accessed 10/09/21];
3. Source link (2020). ACROS Fukuoka Prefectural International Hall. Alpharetta, Georgia: Source link LLC. Source link [accessed 10/09/21];
4. Velazquez, L (2020). Featured Project: ACROS Fukuoka Prefectural International Hall. Alpharetta, Georgia: Source link LLC. Source link [accessed 10/09/21];
5. National Design Academy (2015). Vertical Gardens and Sustainable Design: Theme of the Month: Bringing The Outdoors Indoors, Vertical Gardens & Sustainable Design. Nottingham: National Design Academy. Source link [accessed 15/09/21];
6. Emilio Ambasz & Associates Inc. (no date). Fukuoka (Japan): Prefectural International Hall. New York: Emilio Ambasz & Associates Inc. Source link [accessed 15/09/21];
7. ACROS Fukuoka Foundation (no date). Foundation Overview. Fukuoka, Japan: ACROS Fukuoka Foundation. Source link [accessed 15/09/21];
8. Fukuoka City (2014). Fukuoka City Environmental Basic Plan. 3rd Edition. Fukuoka, Japan. Source link [accessed 15/09/21];
9. Mabon, L, Kondo, K, Kanekiyo, H, Hayabuchi, Y and Yamaguchi, A (2019). Fukuoka: Adapting to climate change through urban green space and the built environment? Cities, Volume 93, Pages 273-285. Source link [Accessed 15/09/21]; and
10. Fukuoka City (2009). New green basic plan (in Japanese). Fukuoka City Government, Fukuoka. Source link [accessed 15/09/21, as signposted by Ref. 9].
ACROS Fukuoka Prefectural International Hall in 1995
ACROS Fukuoka Prefectural International Hall in 1995
https://www.acros.or.jp/english/floor/stepgarden.html#
ACROS Fukuoka Prefectural International Hall situated in the wider city landscape
ACROS Fukuoka Prefectural International Hall Situated in City
https://www.ambasz.com/fukuoka-25th-anniversary
ACROS Thermal Imagery: Takenaka Corporation, Kyushu University, and Nippon Institute of Technology (2000)
ACROS Thermal Imagery: Takenaka Corporation, Kyushu University, and Nippon Institute of Technology (2000)
https://www.greenroofs.com/2020/08/17/featured-project-acros-fukuoka-prefectural-international-hall/
ACROS Fukuoka Prefectural International Hall Design Illustration
ACROS Fukuoka Prefectural International Hall Design Illustration
https://www.ambasz.com/fukuoka-25th-anniversary
Information about this nature-based solution was collected as part of the UNA global extension project funded by the British Academy.