Hydrological Feasibility of Flood Barriers to Protect the Gothenburg (Sweden) during the 21st Century - An Initial Assessment

Other conference contribution, 2014

Climate change due to increasing of greenhouse gas emissions to the atmosphere will cause mean sea level to rise about +1 m by 2100. To prevent coastal floods resulted from the sea level rising, different flood control structures have been built and showed acceptable protection levels at least so far; e.g. Thames Barrier in London, UK. Gothenburg city on the south-west coast of Sweden, with the Göta älv River running through it, is one of vulnerable cities to the accelerated sea level rise. Besides, a high tide in southern Sweden will be increased to +2 m above the current sea level by 2100. Hence, most parts of Gothenburg will experience flooding events during the 21st century, even the City Planning Office of Gothenburg suggests +2.5 m above the current sea level as the safe level for setting the shelter of especially important facilities by 2100. Developing water level model by MATLAB, we investigated the hydrological feasibility of using flood barriers in the Göta älv River to protect the Gothenburg city against flooding events during this century. One flood control barrier at the river upstream (upstream barrier) in the Gothenburg region and a sea barrage (Göta älv barrage) at the entrance point of the river to the North Sea were suggested by this study. Considering three operational scenarios for these barriers, the highest sea level was estimated to +2.95 m above the current mean sea level by 2100. To prove flood protection against such high sea levels, both barriers have to be closed. In order to prevent high water levels in the Göta älv reservoir due to the runoff generation from rainfall, the barriers would be open when the sea level is low. This preliminary assessment concluded the suggested sea and flood barriers would successfully protect the Gothenburg city from flooding events during the 21st century.