- Created by: Woden
- Created on: 20-02-19 16:39
Meteorlogical Causes of Flooding
High precipitation- caused by a low pressure system that is localised to one area for consecutive days.
Saturated ground- no water can be absorbed, therefore there is a lot of surface run-off
Rainfall falling in high land will flow down into valleys, causing the water to collect in one place
Snow melt- causes flash flooding (Nepal)
Humans Exacerbating Flooding
Urbanisation- decreases interception and increases surface run-off
Enhanced Greenhouse Effect-Global Warming-increase in low pressure systems
Redirecting rivers, altered flow direction which can make their capacity for water unpredictable.
Impacts of Flooding
Economic- Tourism industry declines, Damage to infrastructure, destruction of businesses, increased insurance prices, strain on services, crops destroyed.
Social- Injuries, Deaths, Home destroyed, Transport systems ruined, Waterborne diseases, shortage of services and supplies (e.g. healthcare, water, food, medicine), Emotional stress/trauma.
Environmental-Soil Destroyed, Crops ruined, habitats destroyed, livestock killed, pollutants (sewage) released into ecosystems.
UK 2012 Flooding
Catchment size and shape-small catchment area containing small ricer so flooding is unlikely. Catchment shape is long and thin so flood risk is lowered.
Geology Type-mainly granite in upper course leading to higher surface run-off as it's impermeable. Slate in middle/lower course which is more easily eroded so risk of flooding is increased
Urbanisation/Rurality-flooding occurs most in urban area of Helston as surface run-off is high due to impermeable surface and obstructions in the river Cober such as arched bridges which slow the velocity of the river. Rest of river is rural so little flooding as farmland intercept rainwater.
Valley Steepness-areas where valle is steep have higher rates of run-off this is true of the lower region of Helston where flooding occurs the most.
Precipitation-high rainfall in winter often intense and spread over a long duration leading to saturated ground and therefore higher risk of flooding.
120 homes in lower streets of Helston flooded, cars left stranded in the flood water.
High volume of ermegency calls by worried residents so calls had to prioritised to life threatening cases
8000 litres of water pumped from St. Johns Street
Travel around Helston disrupted as roads were flooded
River levels rose to a high 2.14m in places, the normal level is between 0.3m and 1.3m
Environmental Agency pumped Water from Loe Pool using 3 temporary pumps to prevent water backing up the river into Helston
Rescue centre set up to help those displaced by flooding
200 people evactuated from homes at 3am
23 fire engines work to save houses at risk from flooding
Met office issued amber weather warning for heavy rain which stayed in place until Christmas Eve
Severe flood warning issued, 1 of only 4 in the UK
Shelterbox Charity provided blankets to evacuated residents
Specialist water crews carried out door to door visits to support local residents
Food donated to residents from Helston's Farmers Market
Temporary homes offered to those who were unable to return to their homes due to flood damage
Flood management in terms of channel maintenance which is only carried out where it's essential to control flood risks
Investigation of lins between land management, run-off and flood risk. Land management schemes considered to reduce flood damage in future
Public meeting held to discuss approaches to coping with future flooding