Torrential rainfalls have become part of everyday life in Denmark, due to climate changes. However, our cities are not dimensioned for heavy rain. Therefore, it is necessary to develop our cities and make them more resilient against the still escalating volumes of water. Randkløvehuse, a housing association in Tårnby, has previously struggled with large volumes of water in the basement after torrential rainfalls. In order to prevent future floodings, green storm water infiltration solutions, which are able to absorb large volumes of water, have been installed. The climate proofing solutions applied to the project contribute to a sustainable city development.

Briefly about the project


Previously torrential rainfalls have caused drainage problems at Randkløvehuse. Climate proofing is required, why the Engineering Company Torkil Laursen A/S, in cooperation with the landscape architects Tredje Natur, the housing association Tårnby Huse and Geo, has performed a decoupling of roof run-off, which is an innovative alternative to an expansion of the sewerage network.

From the buildings’ rooftops rain pours through water channels in bowl-shaped green areas in a common courtyard. From there the water is able to infiltrate into the soil or evaporate back into the atmosphere. Applying green solutions, also known as SUDS*, which are not only valuable in relation to climate proofing – they are also a cheaper alternative to an expensive expansion of the existing sewerage network. Furthermore, the overall amenity value will increase for the residents and the biodiversity will maximise.

During the 2-year duration period, the results will produce valuable information about how SUDS can contribute to climate proof our cities.


* In Danish, the expression is LAR-solutions. In the UK LAR is known as SUDS (Sustainable Urban Drainage Systems), in Australia it is WSUD (Water Sensitivity Urban Design) and in the US, it is LID (Low Impact Development). In this text, we have applied the UK expression, due to the proximity to the market.

Fun fact

2 mm

Over the last 100 years, Denmark’s water level has increased with 2 mm a year. The increase is expected to continue for the next 100 years with strong storm surges to follow.

Did you know

Did you know that a precise knowledge of the underground is not only useful in optimised planning of SUDS-solutions? Generally, this knowledge may be applied for better planning, design and construction of underground structures.

Did you know

That green solutions for rainwater infiltration not only contribute to handling large volumes of rain, they can also improve the water quality and increase the groundwater recharge, amenity value and biodiversity in an area?

Fun fact


SUDS is the abbreviation for Sustainable Urban Drainage Systems, which is decoupling of rainwater close to the source.

Fun fact

54 %

54% of the World’s population lives in cities. In 1960, the proportion of urban population was only 34%. The urbanisation continues and with it follows an increasing need for a sustainable transformation of the cities.

Geo's role in the project


To secure an optimal hydraulic performance of SUDS, it is crucial to have an accurate knowledge of the local geological conditions. Prior to the installation of the storm water infiltration solutions, Geo has performed extensive preliminary investigations of the underground and mapped the geological, environmental and hydrological conditions. Apart from this, Geo performed four borings to five metres below surface. The borings have multiple purposes. They have provided a specific knowledge of the underground and have been applied in planning the optimal infiltration system. Furthermore, the borings will be an integrated element in the rooftop decoupling as infiltration wells, which will act as an overflow to a highly permeable sand layer in the underground.

Geo is in charge of monitoring the hydraulic performance of the storm water infiltration systems throughout the duration of the project. The monitoring will provide valuable information on how storm water infiltration can be applied optimally, in order to climate proof our cities.  





Services used in the project
Climate proofing , Subsurface Models , Groundwater Engineering , Soil Investigations
SUDS in Taarnby

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