Rain gardens in Kviberg

Creation of new green areas

The objectives of the project are: 1. To create rain gardens that clean the water from the parking at Kviberg’s multisports arena. 2. Fulfill the city of Göteborg's aim of natural water treatment that the city will strive for. 3. Save the Säveån, a closely located Natura 2000 area from the drained wastewater of the parking space. 4. Reduce the stormwater burden of the city. (Ref. 2, 1)

In some parts of Göteborg floods have been a common problem. In heavy rain, it happens among other things that large amounts of rainwater from water pipes penetrate into wastewater pipes, which may overload them. The consequences are that unclean wastewater flows right into the city's watercourses. At Kviberg's multisport arena, it is extra important to clean the water flowing from the plant because Säveån, a Natura 2000 area, is located close by. In June 2015, the city completed one of the country's first rain gardens. The rain garden is a pilot project (demo site) for sluggish stormwater drainage and is located at the Kviberg's multisport arena. The rain gardens have two functions, to filter pollutants from the parking space and to slow down large water flows to avoid floods when it rains a lot. Using the right material in the plant bed is a must for a functioning plant. The top layer consists of plant soil, in this layer mainly the purification takes place. The water should flow through easily and therefore the soil should have a low content of clay and high sand content. It is also important to have the right content of organic material for the plants to thrive. The second layer is mineral soil and this gives stability to the plant bed. It must not contain too much organic material because then there may be settlements. At the bottom, there is a gravel layer and a drainage pipe to store and collect water. Between the finer grains and the drainage layers, there is a layer of sand that keeps the particles in the right place. (Ref. 1 , 3)

• Local government/Municipality