the natural floodplain if there were no flood defences or certain other manmade structures and channel improvements. 2. Flood Defences The purple line shows all flood defences built in the last five years to protect against river floods with a 1per cent (1 in 100) chance of happening each year, or floods from the sea with a 0.5 per cent (1 in 200) chance of happening each year, together with some, but not all, older defences and defences which protect against smaller floods. Flood defences that are not yet shown, and the areas that benefit from them, will be gradually added. Hatched areas benefit from the flood defences shown, in the event of a river flood with a 1 per cent (1 in 100) chance of happening each year, or a flood from the sea with a 0.5 per cent (1 in 200) chance of happening each year. If the defences were not there, these areas would be flooded. Flood defences do not completely remove the chance of flooding, however, and can be overtopped or fail in extreme weather conditions. 3. Significant, Moderate or Low likelihood of flooding Our assessment of the likelihood of flooding from rivers and the sea at any location is based on the presence and effect of all flood defences, predicted flood levels, and ground levels. By clicking within either of the blue areas of floodplain, you can see which of three further categories of likelihood of flooding (significant, moderate, or low) apply there. 4. Flood