Foto: Sustainable Hospital Odense: Henning Larsen Architects
Sustainable hospital in Odense
A new ‘super hospital’ in Odense, the region of Southern Denmark, is under construction with a new faculty of Health Sciences for the University of Southern Denmark. The 250,000m2 hospital fulfils the vision of the ‘Green Blue Recreational Plan’ of Odense Municipality’s City and Culture Administration, implementing rainwater management solutions that contribute to the distinctive character of the area; a home to open fields, forests, rare and protected plants and rich wildlife. Internal rainwater basins have been created which flow into the nearby river ‘Killerup Rende’, feeding conservation sites downstream. Whilst the hospital is still under construction, birds occupy the basins and the recreational value of the area has already been increased.
The Adaptation Journey
The positive impact
Due to the massive size of the hospital, large amounts of polluted rainwater from the construction site, as well as from the buildings and road facilities once they are constructed, would run-off into the nearby river. The internal management of rainwater in a basin network provides a sustainable solution to this challenge, in harmony with nature. The basins, some of which are covered by plants and filtration soil, purify the water before it enters the nearby river stream. As this results in a ‘wetland’ type environment, more plants and wildlife are attracted to the hospital site, and biodiversity along the river course is protected from pollutants. The flow of surface water into the river has also been unregulated, allowing water to flow into the river causing a sudden rise in water level. With increasing cloud bursts of heavy rainfall, the basins provide extra water storage and slowing the rainwater run-off into the river. This will reduce flooding in the protected conservation sites downstream. The measures increase the recreational value of the area, forming part of a larger “Green Blue Recreational Plan” which aims to ensure that people get the experience of being in nature while being in the middle of an urban area.
How does it work?
The rainwater basins, which are to purify and delay the rainwater run-off, have been laid out creating a wetland system around the otherwise raw construction site of the super hospital. The nearby river is essential to this rainwater management system, as it enables the movement of water from the site into conservation areas downstream, such as the Natura 2000 area ‘Lindved Å’. The alternative to this solution would have been to divert the rainfall run-off into the sewer system, missing out on the biodiversity and water storage gains.
The basin network consists of ponds with permanent water levels and depressions, which in the event of heavy rainfall will fill up and function as temporary ponds. Polluted rainwater, for example from car parks, is cleaned in purification basins or ‘wadis’, which are covered by plants and have a layer of filtration soil at the bottom called. To tailor the solution to the built environment, the rainwater is divided into basins for roof water, polluted water from roads, and cleaner water from areas without traffic. This removes pollutants like oil before the water can move into clean basins and then into the river.
Wetland Rainfall Buffer
The created ‘wetland’ also acts as a buffer for fluctuations in the amount of rain, which is supported by the planting of vegetation that is robust to heavy rain, slowing the flow of water into the river. The total basin network has an approximate volume of 40,000 cubic meters, and is dimensioned to meet the minimum require of the impact of a 20-year rainfall event, however it will be able to handle much more, for example the heavy rainfall of a 100-year event. This wetland formation is also what helps to increase biodiversity in the area, attracting.
Operation and maintenance
The vision for the project was that it would contribute zero rainwater to the sewer.
Obstacles and challenges
The measures were developed as part of the “Green Blue Recreational Plan” an intermediate plan between the municipal and local level. To develop the plan, the interests of different actors needed to be balanced. All of the actors involved in the plan development had to talk about other disciplines in their proposals, and have interdisciplinary dialogues that support the development of consensus.
In sustainable solutions projects like this one, a large obstacle can be the fear that new solutions could put a strain on the project finances. In this case it was important that the solutions were incorporated from the beginning of the project, and a good dialogue was facilitated with the builders where financial concerns could be addressed.
How much did it cost?
The hospital was funded by the ‘State Quality Fund’, and the Region of Southern Denmark and the Danish Building Authority are financing rainfall solution. The construction costs for the establishment of the basin network have amounted to DKK 3-4 million plus costs for basic purchases. It is also worth noting that when no rainwater is discharged to the sewer system, no connection fee is payable. This saving is of a significant nature and has therefore helped to constitute an indirect investment in the project.
Revitalization of water elements Public buildings Urban greenery Water purification and recycling Use of rainwater Biodiversity Floods and torrential rainfall