The River Rhine Case Study

The River Rhine Case Study
The River Rhine rises in the Swiss Alps about 3,353 metres above sea level and flows north, passing through or bordering Switzerland, Liechtenstein, Austria, Germany, France, and the Netherlands and then its mouth is located at the North Sea. The Rhine is usually at its maximum volume during the seasons of spring and summer; this is due to the fact that there is the melted water of snow and glaciers. In this enquiry I am looking at the aspect of river flooding in the Rhine, particularly in 1995. A river flood is when a river spills its banks onto areas of land surrounding it that are not usually covered by water. Causes The main causes for river flooding are: S Heavy rainfall ? causes soil to become saturated and not allow infiltration. S Rapidly melting snow S Dam bursts S Soil saturation ? this may cause a river to flood as the water would not be able to infiltrate the soil and so will encourage overland flow. S Deforestation ? this may cause flooding as there are no trees to intercept the rain and so the soil will become saturated. S Ploughing ? this may cause flooding as it creates gullies which water can flow down towards the river S Urbanisation (extending built up areas) ? this may cause a river to flood as the concrete and tarmac that is laid over the soil send more water to the river than to the fields which they replaced.
As you can gather from the above information the causes can be categorised into human and natural effects. The flooding of the River Rhine in past and recent dates has mainly been caused by human infliction, with only few natural causes. Natural Causes: In early 1995, there was heavy rain over much of Europe and it lasted, almost continuously, from November 1994 up until February 1995. The ground quickly became saturated and any further rain was transferred to rivers as overland flow. Some people think that the effects of global warming have affected the river flooding, as in the last 100 years: S Average temperatures have risen by about 1 degree Celsius in southern Germany. S Winter precipitation in the Rhine catchment has increased by 40%. Human Causes: S Much of the Rhine?s riverside marsh and floodplain, which was used to hold back floodwater, has been replaced by farmland or building. S Improved flood protection measures upstream cause the floodwater to move downstream more quickly than it used to. S The river has been involved in a straightening process due to improved navigation for shipping; this means that the distance has been reduced by 50km whereas before it was 1320km, so in turn this means that water moves downstream more quickly. S Urbanisation in the Rhine catchment area has also helped flooding due to the fact that the concrete and tarmac send more water to the river than the fields they replaced. S There has been a change from pastoral to arable land in rural areas and in effect hedgerows and meadows have been removed and replaced with ploughed fields. This reduces the capacity for infiltration and interception, due to removal of vegetation, so a larger percentage of rain falling on the catchment goes into the river. S The upper Rhine is used for generating hydroelectric power; 10 power stations are bypassed by a new channel parallel to the old river, designed to remove water which is surplus to the generators? requirements. S A flood surge now occurs over just 2 days, whereas before it was spread over 5, so the same volume of water is now moving further in a shorter time, causing a dramatic rise in the river?s level. Results There were many results to come of the flooding in 1995, both short and long term. Much of the land consists of polders which are low-lying areas that are enclosed by protective embankments called dykes, but in 1995 many of these polders were flooded. As many of the dykes are made of sand and clay they became saturated because of the continuous high river levels, this made them more likely to collapse so that emergency work on reinforcing them had to be carried out. Many homes were flooded and so many people had to be evacuated, this left their homes liable to looting, so soldiers and police had to guard the empty houses. Also 1 million cattle were evacuated in order to keep them alive ? this resulted in some of them becoming infected with foot rot and reduced milk yields. In addition to this, 4 people were killed and some roads became impassable due to the excessive amount of water coverage, along with waterways which were closed for 2 weeks leaving many oil and dry bulk barges stranded. Stocks of fruits, flowers and vegetables were lost due to greenhouses becoming flooded. Overall the destruction caused by the floods cost millions of pounds. Response Short Term: After the flood in 1995 quick measures had to be put into action to avoid further damage. S Sandbags and temporary barriers were placed across doors and windows to help prevent water entering the building. S Doors and window frames sealed with putty or foam. S Removal of carpets and furniture to higher floors to stop them from being ruined. S Evacuation of people and livestock to prevent loss of life. S Clear underground car parks, subways and underpasses. S Portable pumps were installed. S Temporary dykes were constructed. S Roads that were at risk of flooding were closed so cars travelling along it would not get stranded. Long Term: After the devastation was seen from the flooding in the Rhine, the people realised what effect flooding can have; so permanent, long term measures were put into place to stop these things ever happening again. S Afforestation, planting of trees, was encouraged in the Rhine drainage basin to increase the amount of rain that is intercepted. S Reinforce earth dykes with steel piling and line them with stone blocks to reduce erosion of the dykes by abrasion during floods. S Limit residential development in areas which are likely to flood. S Encourage individual households to reduce flood risks in their own homes; these include things such as tiled floors downstairs and removable items of furniture. S £5 billion has been spent on a system of protective dykes after 1,800 people were drowned in 1953 due to flooding. S After the 1995 floods a further £1 billion was being planned to be spent on flood protection. S Remove silt from the forelands, the silt could be used to build bricks or dykes, which would otherwise slowly lose their capacity to hold floodwater as one flood after another deposits silt. S Encourage land uses in the Rhine basin which increase absorption of rainwater such as contour ploughing and increasing the area of gardens and parks in urban areas. S Flood retention basins could be built, these are areas of land surrounded by dykes in which flood water is directed into to reduce the river?s water level. When the flood is gone the water from the basin is slowly transferred back into the channel. S Allow the river to flow back through marshland areas which had been previously sealed off for navigation purposes

The River Rhine Case Study 8.3 of 10 on the basis of 3512 Review.