Foto: Rayss Group Sp. z o.o. Sp. k.
Pocket Retention Park: Expression Passage on the IDEA Multi-Family Estate
Honourable mention in the Adapterra Awards 2020
Climate change is currently one of the most serious problems of the cities. Green Infrastructure is the best tool not only to adapt but also to mitigate these changes. We have developed an original methodology, in which 'working greenery' is cheap and its functionality and ecosystem values are easily translated into the engineering and design language. This Retention Park is one of our Best Practice showing our methodology 'in action'.
The Adaptation Journey
The positive impact
One of the main goals was to mitigate the effects of drought by compensating the days without rainfall with the rainwater accumulated in rain gardens. Another goal was to reduce the risk of floods by relieving the inefficient local water drainage system.
Thanks to reducing concrete surface ratio in favour of the green ratio, the place has changed from a heat island with impermeable surface to a space supporting biodiversity growth, phytoremediation and groundwater recharge.
How does it work?
The pocket Park will be the first in the District (there is no public Park within a radius of more than 1 km. Total area of the IDEA Pocket Park with the Passage is around 0,5 ha and surface with greenery increased from 10% to 64% covering now over 3 000 m2 and including 56 trees, 52 species of flowers and shrubs, lowering the impact of heat waves and decreasing the risk of droughts.
The park can now retain 54 m3 of water which, thanks to capillary forces and horizontal flow of water in the soil layers, also supplies the surrounding green areas and mitigating the risk of floods.
The whole Estate and The Park area is with no fence and with free access which is unusual in the are. During the construction works, the park was already used as a site for numerous educational study trips, as the good practice for Retention Park and raingardens example, which is still quite unique in Poland.
Before the construction of the Park, the area was part of the exhibition grounds serviced by the municipal company Targi Gdańskie. The space was dominated by sealed impermeable surfaces and roofs of the exhibition halls. In the spring and summer, it was associated with the intensification of the urban heat island phenomenon and periodic drought, interspersed with local flooding accompanying torrential rainfall. These problems were exacerbated by local difficulties in the capacity of the city's rainwater drainage network.
Operation and maintenance
Due to the fact that the vegetation is designed from mostly native species, carefully selected for the habitat, growing in a naturalistic composition, it does not require intensive care.
The project in the first version was much poorer, both in design of street furniture and the density and richness of green plantings. During the design and implementation of the project (which was done in phases), the Developer, seeing the first effects and functionality of the park, allowed us to do much more which is extremely rare in this industry. This is evidently thanks to Green Infrastructure!
Why was the measure chosen?
In the early design phase, the introduction of a traditional pedestrian path, separated from a bicycle path, with an underground drainage system was considered. However, numerous benefits related to the construction of the retention park and the integration of the passage area into the composition of the entire Estate outweighed.
The greatest risk is associated with possible maintenance errors, such as excessive mowing.
Obstacles and challenges
The greatest difficulty was the joint coordination of design work in a multi-discipline team of specialists. Especially, that simplified technical solutions were used in relation to those used traditionally, which is often a concern among engineers accustomed to pipes instead of plants. The evaluation of ecosystem services is always the problem.
Everyone involved in the creation of urban structures knows that green infrastructure is most capable to mitigate climate changes, unfortunately not everyone knows how to translate this knowledge into implementation and design practice.
How much did it cost?
Total cost: 300 000 EUR.
Financed by private developer.
The return for whole IDEA Multifamily Estate Development - last building will be completed in the 2021.
The cost of traditional underground drainage infrastructure: 18,000 EUR.
Revitalization of water elements Urban greenery Water purification and recycling Use of rainwater Shading Biodiversity Heat waves and thermal island Floods and torrential rainfall Lack of water and drought