Let nature do the work

The strategy let nature do the work focuses on incorporating greenery and water as active components in the design and operation of the city. The ‘green and blue’ infrastructure replace and complements active technical solutions, creates a richer biodiversity, and promotes human health and well-being.

In a city where green space and water is carefully considered, prioritised and implemented in the city planning, the ‘green and blue’ natural infrastructure can fill several functions, contribute to synergies, and supply ecosystem services. To date a total of 77,055 m² of green space, such as green oases, green courtyards, and green roofs have been established in Stockholm Royal Seaport.

Table 4.1 Key figures for let nature do the work

Etapp	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1
	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1
Status	Completed	Planned	Planned	Planned	Completed	Completed
Proportion green area of total area, %	33	34	17	67	39	46
Green oasis*, m²/residents	6,2	5,5	Not relevant	18	5,6	11,7

* Green oasis is green public open spaces with social values.

Green structures in public space

Incorporating high-quality green areas in the public space is crucial to enable ecosystem services. All stormwater from the public space and excess water from the properties is, via inflow basins, led to plant beds consisting of a mixture of gravel, biochar and compost. The plant beds stores the water and ensures healthy plant growth. The plant beds temporarily detain the water which is then slowly discharged into Husarviken. In case of a downpour, ponds and watercourses have been designed to detain the water that otherwise would have caused flooding. Public parks and other green areas have been designed with capacity to store large quantities of water. Planted trees give shade, regulate the temperature, and reduce the effects of heat waves. Green areas also provide possibilities for recreation, peace, and proximity to nature.

Public green space accounts to 26% for the first two completed phases. In total, almost 50,000 m²of green parks have been built, which is equivalent to an average of 20 m² per residential apartment. See table 4.1 above.

Tabell 4.2 Green structure public space

Etapp	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1
	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1
Status	Completed	Planned	Planned	Planned	Completed	Completed
Share of apartments that have access to parks and nature areas within 200 m	100%	100%	Not relevant	100%	100%	100%
Park, m² per apartment	18	12	Not relevant	39	12	30
Rain gardens m²	700	400	38	UU	2 350	0
Plant beds, m²	137	904	500	UU	64	0
Trees, piece	120	104	66	UU	209	118

*UU: Ongoing feasibility studies

Access to nature and green areas promote health and well-being. In Stockholm Royal Seaport the maximum walking distance a property to green area is 200 meters. See map below.

Map 4.1 Park and green areas within 200 meters

Stockholm Royal Seaport is located adjacent to the Royal National City Park, and the green structure in the northern part of the district is of great importance, as it is part of a dispersal network for species that live in oak-trees, as well as amphibians. In the planning and construction process, these environments have been preserved and enhanced by planting trees, as well as by building wetlands, pond, and a tunnel for the amphibians. Within the development, there are threatened red-listed and protected species, see map below.

Karta 4.2 Important dispersal patterns between Stockholm Royal Seaport and the Royal National City Park.

Green structure on development sites

The use of the Stockholm Royal Seaports Green Space Index (GSI), in combination with its stormwater water strategy contributes to well thought through solutions that benefits both nature, stormwater water detention and recreational qualities, within the building developments.
The size of the properties’ individual courtyards, roofs, and walls determines the size of eco-efficient surfaces required.

To achieve the set targets it is important that developers, architects and landscape architects collaborate in the early stages. In addition, the correctly constructed plant beds with ample soil depths, a large amount and variety of plants, and serially connected surface water solutions that supply the vegetation with water, are crucial for a good outcome.

In total, 16,700 m² of green roofs, and 12,850 m² of green courtyards have been built to date. See table 4.3 below.

Requirements:

Norra 1 and Västra have voluntary commitments.
A minimum Green Space Index of 0.6 for residential buildings and 0.4 for commercial buildings shall be achieved.
Existing buildings in Gasverket are not included for cultural and historical reasons.

Map 4.3 Green roofs and Green Space Index per courtyard and property developer

Etapp/xx	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1	Värtaterminalen
	Norra 2	Brofästet	Gasverket Västra	Gasklocka 4	Västra	Norra 1	Värtaterminalen
Status	Completed	Planned	Planned	Planned	Completed	Completed	Completed
Proportion court yards that fulfills GYF	100%	100%	100%	100%	11%	25%	100%
Proportion green roofs of total roof’s surface	44%	35%	32%	57%	44%	14%	27%

Average Green Space Index for each phase

The first two phases, Norra 1 and Västra, lacked Green Space Index requirements when design began, as shown in chart below. The results show that in early design stages Green Space Index is higher than the final result. There are several reasons for this, for instance, lack of coordination between various disciplines such as architects, landscape architects, and structural and water and sanitation engineers. In the developments later phases there are plans to incorporate green roofs that can be used by the residents and at the same time provide several ecological values, so-called biotope roofs.

Diagram 4.1 Green Space Index in average per phase

Norra 2

Norra 2 was the first phase with strict sustainability requirements. All developers met the requirements, but the high ambitions at the beginning of the process had to be modified during the course of the work. For example, the weight of the green roofs had not been properly accounted for in the structural design, which led to modifications, such as thinner sedum roofs. All roofs, courtyards, as well as several of the walls had to be used to achieve the requirements. The courtyards are designed to be used by the residents and are perceived to be greener than those built in the earlier phases.

Diagram 4.2 Measured GIS per courtyard, Norra 2

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Stora Sjöfallet (Bonava, SSM, Viktor Hanson, Wallenstam): The development features varied green roofs not only sedum roofs, three large oaks, creepers on the façade and integrated balcony drawers, birdhouses and bat ferrules. It also features design ideas like meadows and swamp forests.
Hornslandet (Stockholmshem): The development features trees, such as oaks and fruit trees, flowering perennials, edible plants, flowering plants spread out over the whole season, creepers on pergolas and wires on the gable, with possibilities for cultivation on the terrace, the water discharges on trellised wall.
Sonfjället (Erik Wallin, HEBA, Skanska): The development features a willow tree house, integrated flower boxes, natural species selection, rain garden, deep plant beds, edible plants, climbing plants on the houses in harmony with the architecture of the buildings.

Brofästet

In Brofästet, the Green Space Index requirements were exceeded with a larger margin during the design stage than in Norra 2. It is clear that the understanding of Green Space Index had increased, and that a system approach to the management of stormwater and integrated planting areas had been adopted early in the design process.

Diagram 4.3 Measured GIS per courtyard, Brofästet

Backåkra, courtyard 1 (Besqab, Oscar Properties, Åke Sundvall): This development features a courtyard with good plant depth, integrated groundwater, bushes with edible berries, rain gardens, green façades, well-planned social areas.
Backåkra, courtyard 2 (Stockholmshem, Tobin Properties, Einar Mattsson): The development features large areas of unstructured ground, large interconnected green roofs, great soil depth over the system of joists of 800 mm. Almost half of the green roofs are meadow-roofs which benefit bees and butterflies. Continuous stormwater management with a combined system of roofs and rain beds (local green-blue stormwater management).
Koppången, courtyard 1 (HSB, Riksbyggen): All buildings have roof terraces that are available for residence. One of the roofs have a biotop-roof with dead wood and varied vegetation. Many social areas have pergolas and grass areas for playing. A large oak is situated in the center of the courtyard. Stormwater management is integrated into the courtyard design.
Koppången, courtyard 2 (Einar Mattsson): This development features a small and dark courtyard and a roof terrace with visible a green wall on the gable.

Gasverket Västra

Due to their cultural and historical values of the buildings in Gasverket Västra the existing buildings are omitted from the requirements.

The surface area surrounding the sports centre, the school, and the preschool are subjected to a greater use than other courtyards, this makes it more difficult to achieve all the requirements. The school require hard surfaces for the kids to play on, this meant that the vegetation had to be placed on the border zones, roofs, and vertical surfaces.

Hjorthagshallen (Fastighetskontoret): Achieves a GSI of 0.65. The plans for the sports center include creepers on wires along the facade and skeletal soil with stormwater-irrigated trees and sedum roofs.
Bobergsskolan (SISAB): Achieves a GSI of 0.59. The school yard is small, and will suffer a lot of wear and tear and therfore require hardened surfaces. In total the surfaces achieve the requirements for the common courtyard.
Förskolan (SISAB): Achieves a GSI of 0.66. The preschool has sedum roofs, fruit trees and flowering trees and bushes as well as creepers on the fence.

Gasklocka 4

Gasklocka 4 differs from other neighbourhoods in the district, as the surface of the courtyard is larger, which creates an atmosphere of a public park, with several social areas. The greenery consists of meadows and woodlands, with both open and dense areas, that create different rooms.

Gasometer, (Oscar Properties): Achieves a GSI of 0.76. Besides a large courtyard providing a ‘park feeling’ there are plans for a roof terrace and a green roof. Deep plant beds are made possible by the fact that a large proportion of the soil is not structured. In addition an amphitheatre, seating areas in a pergola and many trees are being planned.

Södra Värtan

In general the early design for Södra Värtan exceeds the GSI requirements.

The area plans top use green roofs a more extensively than in previous phases, for example, several biotope roofs, and roof terraces with social qualities are being planned.

Värtaterminalen

Ports of Stockholm have achieved a GSI of 0.39. The terminal has a green roof that covers about 50% of its areas with many perennial plants, which makes the roof feel like a garden.

Norra 1

The voluntary requirements have not been met, as they were introduced too late in the planning process. Consequently, the results have not been reviewed by the City of Stockholm and are based on reports by the developers.

Diagram 4.4 Measured GSI per courtyard, Norra 1

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Abisko (Reinhold Gustafsson, Lennart Ericsson, Erik Wallin, Järntorget, Viktor Hanson): Reinhold Gustafsson has a green roof.
Garphyttan (Seniorgården, NCC): The courtyard has a relatively large eco-effective area due to partly non-structured greenery.
Gotska Sandön (Familjebostäder, SBC Bo): The courtyard has shallow plant beds and no green roofs.
Skuleskogen (Svenska Hus): The courtyard has shallow plant beds due to structured greenery.

Västra

Diagram 4.5 Measured GSI per courtyard, Västra

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Kosterhavet (ByggVesta): The courtyard har shallow plant beds and a smaller green roof.
Färnebofjärden (Einar Mattsson, Järntorget): Shallow plant beds due to structured greenery and a shaded courtyard, which limits the conditions for plants. Both roofs has sedum roofs.
Söderåsen (Svenska Bostäder): The courtyard is small with a large hardened surface area.
Tresticklan (HSB, JM): The courtyard has shallow plant beds and a few visible sedum roofs.
Tyresta (Borätt, JM): The buildings have green roofs and a structured courtyard.
Töfsingdalen (Stockholmshem): The courtyard has bushes and plant beds with a varying degree of depths. The roofs are partially sedum.
Norra Kvill och Padjelanda (Primula): A large part of the courtyard is not structured which makes a greater soil depth possible.
Muddus (SKB): The courtyard has deep plant beds which creates good growing conditions for trees. The building has a green roof.
Björnlandet (Svenska Bostäder): The courtyard has plant beds of various depths as well as a number of smaller trees. One of the roof’s is sedum.

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Introduction of strategy

(Only in Swedish)

Key figures

So far 16 700 m² green roofs has been built.
100% of the residents have a park within 200 meters
8,2 m² green oasis per inhabitant.

Green Space Index

Green Space Index is a tool for calculating the eco-efficient surface, i.e. the surface that contributes positively to the ecosystem and the local climate of the area, as well as social values related to greenery and/or water.

Ecosystem services

Ecosystem services consist of all the various benefits that humans obtain from nature, and that contribute to our welfare and quality of life. Urban nature is more than just decoration for the city’s residents, it also has many important functions. Through good planning, one green area can contribute to improved public health, provide food for insects, reduce noise, and manage rainwater, all at the same time.