The Lynmouth Floods

The Lynm let onh FloodsCase Study Lyn gumshieldLynmouth is a village in Devon, England, on the north edge of Exmoor. The village is on the converge point of the due west Lyn and East Lyn rivers, in a gorge 700 feet (210 m) below Lynton, to which it is connected by the Lynton and Lynmouth Cliff Railway. The two villages are governed at local anesthetic level by Lynton and Lynmouth Town Council. Lynmouth is rural airfield with not oft corporate activity going on. It is in the coastal part of the coupled Kingdom Island, which makes it a large tourist attraction spot. People unremarkably come to Lynmouth for Tourism and the activities they do are mainly horseback riding, look for and boat rides.Flood in 1952On the 15th and 16th of magisterial 1952, a storm of tropical started over in south-west England, set up 229 millimetres (9.0 in) of rain within 24 hours on a coastal area, Exmoor. It is perspective that a cold front started a thunderstorm, and the storm worsened. An immedi ate come along run-off occurred and it caused a flash flood. Large amounts of floodwaters moved down the northern part, converge upon the village of Lynmouth in particular, in the upper West Lyn valley, a decametre was formed by fallen trees. This caused potential energy to form and subsequently a while the water broke through the dam move a huge wave of water and fragments down that river. Overnight, over degree centigrade buildings were destroyed or seriously damaged along with 28 of the 31 bridges, and 38 cars were washed out to sea. In total, 34 people died, with a further 420 made homeless. Overall the rainstorm lasted about fourteen hours and 300 cardinal gallons of rain precipitated.Cause of the FloodThe down(p) but steep sided waste pipe basin in which Lynmouth was situated increased the risk of flooding in the area. The steep sides encouraged greater control show up runoff and combined with the small drainage basin size meant any water could reach the river reaso nably rapidly. This was made worse by the high drainage density of the area due to the impermeable rocks of the area roughly Exmoor which formed the source of the river once more increasing the amount of surface runoff following rainfall. Prior to marvellous 15th 1952 Lynmouth had received above average rainfall for 12 out of the first 14 days of the month meaning the dirts were already alter and the river levels high. On August 15th a heavy thunderstorm resulted in 200mm falling in 14 hours, one of the three heaviest rainfalls recorded in the UK. This heavy rain combined with the saturated ground and rapid surface runoff resulted in a huge volume of water silklike down the river. As Lynmouth is situated at the confluence of the East and West Lyn rivers the volume of water was increased further at this point and the was removed beyond the capacity of the river manoeuvre causing the river to burst its banks. This resulted in ruin floods as the West Lyn which had been divert ed during the construction of parts of Lynmouth retook its natural course, silky straight through the village.PreventionFollowing the Lynmouth flood disaster, flood worry plans were put in place to try and ensure such a disaster could not happen again by managing any surplus rain water so that the River could handle it in the in the future.A number of flood management strategies were put in placeThe mouth of the East Lyn was widened to increase capacity and allow water to quickly flit into the Bristol ChannelThe West Lyn was straightened to increase channel efficiency straightening the channel slenderises skirmish and increases velocity, enabling water to travel through the channel as quickly as possible making it more efficient in deal with flood watersThe West Lyn was not redirected, instead cosmos allowed to follow its natural courseFloodplain zoning was used to identify areas around the river most at risk from flooding. Building restrictions were then put in place with areas close to the river which are most prone to flooding being left as open spaces such as car parks.bridge were made wider and taller to allow flood water to tr avel quickly beneath them and to reduce the likelihood of debris becoming trapped and acting like a dam as had happened in 1952Embankments were built by the river to increase channel capacity and reduce the likelihood of floodingMore trees were planted upstream in the source area to try and reduce initial surface runoff through interception and the soaking up of water. Tree roots likewise help to improve infiltration by opening up the soil and slowing down the rate at which water reaches the ground