Öresund is the strait between Skåne and Zealand, and part of the national border between Sweden and Denmark runs here. Since Öresund offers the shortest route between the Baltic Sea and the North Sea/Atlantic for most ships, it is one of the world's busiest straits.

At high sea levels, the sea, from Öresund, presses into the stormwater pipe and fills the system with seawater. Pumping stations are standing by and pumping seawater that never runs out, which in turn risks overloading the pumping stations or flooding properties.