Carsten Dierkes, Terry Lucke
Friday 3 july 2015
12:48 - 12:51h at Europe 2 (level 0)
Themes: (T) Extreme events, natural variability and climate change, (ST) Flood resilient cities and infrastructures, Poster pitches
Parallel session: Poster pitches: 15I. Extreme - Society & Resilienty
Every day in Germany an area of 90 football fields is sealed - around 75 hectares. The effect is alarming: the whole water balance is disrupted because stormwater can no longer naturally infiltrate into the underground. This leads to increased local flooding. Simply diverting the stormwater into the existing sewer systems increasingly overwhelms their capacities and threatens receiving waters. In addition to this, infiltrating pollutants from trafficked areas compromises the groundwater. This situation will become even more dramatic in future in the light of expected climate change. All research indicates that the intensity of the summer rainfall in Germany will increase substantially. Sustainable solutions for handling stormwater closer to the natural water cycle are urgently required. Legislators have also recognized this situation. While the capacity of existing sewers in Germany is in the range of 50 mm/h, permeable pavers can easily infiltrate more than 500 mm/h. But permeable pavements were not used as intensive as possible. One reason for that is the often poor and technical looking design of actual pavers. Permeable systems do not meet the design demands of landscape architects and they have important disadvantages like wide infiltration joints that can cause structural damage to the surface and are not practical for high heels or trolleys. The paper describes the development of a new system of concrete interlocking pavers that only has a width of the joints between 5 and 6 mm according to the German building regulations. There is no limit in shapes, colors and surface finishing any more. An innovative joint filling material was engineered that has a very high strength and a high pollutant removal capacity. The new system fulfills all necessities for stormwater treatment and infiltration and got the German general technical approval. Furthermore it was observed in a field test at three different sites in Germany and the Netherlands over a period of three years and also the cleaning process to renew the hydraulic permeability was tested and optimized. The paper contains results from laboratory and field tests and gives recommendations for construction and maintenance of the new system.