|
River Flooding
What is the impact on people and places? It may seem hard to believe that a small, slow-flowing stream or gentle river could cause serious damage to people and the places in which they live and work, but looks can be deceptive! People love to live near to rivers - in the past mainly for food, water, transport and protection. Even today people enjoy the peace and tranquility flowing water can offer. Flooding can turn even the most harmless looking watercourse into a raging torrent of large-scale destruction - buildings may prove no obstacle to its power; food crops may be ruined leading to food shortages and even starvation; peoples lives may be lost through drowning disease and homelessness. Rivers can be things of beauty and the historic lifeblood of a settlement. Begin to find out how man uses flowing water to enhance life and living, whilst trying to contain its destructive powers when in flood, using the enquiry resources of the Internet! Why do Rivers Flood? Why do Rivers Flood?Floods are natural events. They mainly happen when the river catchment, (that is the area of land that feeds water into the river and the streams that flow into the main river) receives greater than usual amounts of water (for example through rainfall or melting snow). The river cannot cope and this extra water causes the level of the water in the river to rise and a flood to take place. This flooding may take place at any point along the river course and not necessarily at the place where the extra water has entered.
Man Using Flooding RiversAlthough man often seeks to protect himself and his property from the often-damaging effect of floods, man can use them to his advantage. The people of Egypt used the regular event of the River Nile flood to their advantage. Until 1970, the Nile had flooded every Spring as the mountain snows melted. This flooding of the flat land (floodplains) alongside the river enriched the soils leaving behind rich silt in which crops could be grown. The construction of the Aswan Dam in the 1960's meant that from 1970 the annual flood was controlled - many people do not agree with interfering with nature!
Web-Links to Investigate General information on Egypt http://www.arab.net/egypt/geography/egypt_geography.html Ancient Egypt http://www.ancientegypt.co.uk/menu.html The Aswan Dam http://www.mrdowling.com/607-aswandam.html The Geography of the Nile http://www.internet-at-work.com/hos_mcgrane/egypt/egypt2.htm How Can Man Control River Flooding?Man has long tried, not always successfully, to control and prevent the damaging effects of flooding rivers. River engineers may build artificial flood banks, straighten the river course, or dredge the riverbed to make it deeper. All of these methods of control can work, although they often have a negative effect on the river as a habitat. The Environment Agency has a major role in the control of river flooding and the protection of people and their property. Their job is a difficult one has there is an increasing tendency of rivers towards 'flash flooding' - this is where rainfall or melting ice and snow result in a rivers level rising extremely quickly, often far more quickly than in past years. We saw a lot of this during November 2000! (Find out more ( http://www.environment-agency.gov.uk) Thames Barrier the world's largest movable flood barrier, spans 520 metres (a third of a mile) across the Thames at Woolwich Reach, South East London, where it protects the UK's capital city from flooding.
River Floods in the News
Following very severe storms and heavy rainfall in the UK in November 2000 there was flooding in many parts of the country. Travelling around the country was difficult and many homes were flooded, causing many families to leave their homes. Photograph: Escaping the Flood - People in Mozambique cling to the tops of trees waiting to be rescued. (BBC 2000) The floods in Mozambique in 2000 were devastating in their extent and impact on life. These floods claimed many lives and left thousands of survivors homeless and with shortages in food, clean water and employment. Amazing stories of survival against the odds and bravery were reported daily in newspapers worldwide - including the mother who gave birth to a child in a treetop, where she was escaping the rising floodwaters waiting to be rescued by helicopter.
Web-Links to Investigate http://news.bbc.co.uk/hi/english/world/africa/newsid_662000/662472.stm http://news.bbc.co.uk/hi/english/world/africa/newsid_655000/655510.stm http://news.bbc.co.uk/hi/english/world/africa/newsid_662000/662847.stm |