Netherlands Flood Causes
Natural CausesThe cause of the floods in Netherlands, was abnormally high rainfall for 3 months combined with unusually mild temperatures. This melted the snowy mountains to produce a massive torrent of water. Over the past century, average temperatures in southern Germany have increased by between 1°C – 1.5°C. Rainfall in the Rhine catchment area has risen and winter precipitation has increased by 40%.
The catastrophic flooding might be an early sign of a change in the climate caused by global warming. The growing concentration of 'greenhouse gases' could lead to even milder winters in N.W. Europe and hotter, drier summers. For a large section of its course in Germany, the Rhine flows through a narrow gorge which restricts the amount of land either side available to soak up flood water. This increases the flood problem downstream. |
Human CausesDeforestation in the Alps has reduced interception and soil storage of water and increased rates of surface runoff. Urbanization of the floodplain, with water flowing off roofs and roads into drains leading directly to the river has increased river levels after heavy rain rapidly. Excess water would flow out over marshes and floodplains. These acted like sponges, soaking up the water, but now some of the land has been cemented and asphalted for buildings and roads.
Embankments have been strengthened and raised to protect residential and industrial areas, but raising them has closed off former flood meadows. Steep concrete flood walls along the upstream river banks channel flood water quickly towards the down stream cause massive problems down stream. When a storm takes place the flow of water does not increase straight away. This is because of lag time between the high rainfall and the peak discharge. A river with a short time lag and high discharge increases the danger of flooding. Stretches of the Rhine have been straightened and banks heightened, cutting some 50 kilometres off the river's 1,320 kilometre meander to the sea.(Rhine River Floods, May 2013) This has doubled the speed of the river. When there is heavy snow or rain upstream, water cascades down to flood at the mouth, instead of soaking into marshes near its source. |