in tennessee in august as over 400 millimetres of rain falls injust 24 hours. a new state record. and vehicles are tossed around in a torrent in turkey in august as flooding causes chaos in northern parts of the country. scientists say we are unprepared for extreme rainfall. too often action comes after rather than before a flood. where i'm standing now is a reservoir in berkshire. it is supposed to be empty but it is one of a number that have been developed here and are designed to fill up with flood water to prevent it rushing unchecked towards the town of thatcham over there. that's what happened back in 2007 when over 1000 homes were flooded here as nearly 100 millimetres of rain fell in just 24 hours. the flood prompted this scheme to build these reservoirs with this one alone capable of holding 25,000