How Are Floods Caused?
Flooding – Water at times overflows in huge amounts onto normal dry land when floods are caused. Land gets submerged with the overflowing water leading to a deluge. Water in its most violent and cruel expression is called a flood. Lots of people get killed, crops and houses get damaged along with excessive destruction. Floods are basically of two types, out of which one is catastrophic floods and the other is natural floods. When water in huge volumes from oceans, rivers, oceans, lakes, downpours, heavy rains, tsunamis etc overflows, it leads to natural floods.
At times due to the bursting of a dam or an unexpected event, catastrophic floods are caused. Flooding is caused by heavy rains, when water levels in lakes, oceans and lakes increases above the dam or bank leading to an overflow. It flows into neighboring areas and caused destruction. When global temperature rises, there is heavy melting of snow causing floods. In areas that lie low below the level of the sea, floods occur. Floods are also caused by human intervention like cutting down of trees, erosion of soil and settling of eroded soil on sea and river bottom, leading to increase in water levels in seas and rivers to cause floods.
Regions Of The World Where Floods Occur Most
Some of the regions across the world are prone to constant flooding. In Thailand during the monsoon season of 2011 there was severe flooding. The tropical storm Nock – ten was triggered by a landfall and all through the provinces of Central, Northern and Northeastern Thailand along the Chao Phraya and the Mekong river basins, the floods gradually spread in the month of July. By the month of October the waters of the floods reached the Chao Phraya river mouth and also caused flooding in Bangkok the capital city and till the beginning of 2012 the floods persisted.
The floods led to several deaths, and a lot of people were affected and some went missing.
Due to the floods many of the provinces were declared as disaster zones. It was one of the worst flooding of its times. Low lying areas are mainly affected by floods. Many of the countries or regions surrounded by lots of water such as Phillippines, Japan, Sri Lanka etc are regions where floods can affect people badly. Many floods have been reported to occur in different parts of America and Mexico as well where severe destruction was caused due to heavy flooding.
Impact Of Floods On Human Life
The impact of floods can be very costly to human life and property. The flood can ruin homes forever especially if after the flooding, measures for restoration against damages due to water are not taken. Hurricanes and storms are caused when there is the meeting of cold and warm moist air, leading to huge floods. The sewage systems etc are not able to manage excess water due to which flood waters spill everywhere making it difficult to manage. Floods can cause tremendous loss to life, animals, vegetation, crops, property, infrastructure, buildings, homes, etc. Walls get damaged, insulation in walls gets affected, repainting and retexturing needs to be done, etc besides damage to property at home, offices, etc.
In other words floods have an impact on communities and individuals and have environmental, social and economic consequences. Depending upon the extent and location and the flooding health conditions of people deteriorate due to diseases that are waterborne. Damage is caused to power plants, communication links, bridges, industries, roads etc. People at times have no other choice but to leave their homes and relocate themselves till the floods subside. Besides this there is a lot of restoration work to do which is again a costly affair.
Effect Of Floods On Environment
Flooding is a phenomenon that occurs naturally and has both negative and positive impact on the environment. Floods help in maintaining fertility of the soil and habitats within the eco system. Activities of humans have affected the nature of flooding and the flood plains. Land clearance, wetland drainage, developments upstream, channel construction, reservoirs and levees etc change the cycle of floods leading to increase in runoff, water pollution and destruction of habitat. As far as environment is considered this proves to be very destructive.
Floods also lead to breeding events being triggered, dispersal and migration. Floods also affect positively. Ground water resources get recharged, fish stocks increase and recreational environment is maintained well.
As part of negative effect, floods can destroy, vegetation, live stock, infrastructure, property, soil erosion, hill slope degradation, transfer of nutrients and sediments etc. Food resources in the coastal areas can get contaminated, production in the coastal areas gets reduced, quality of water gets lowered and aquatic habitats get degraded etc as well as part of negative effect of flooding. Excess debris, heavy metals, chemicals, excess nutrients and sediments are also introduced mainly due to flooding of marine environments in coastal regions.
Ways To Prevent Floods
Flooding is caused downstream due to rain water that rushes into the rivers and drains. In such a case the water can be held back so that it can be released later on. Rivers are straightened and widening of drainage systems is done in an effort to mitigate flooding. This is done so that rainwater gushing from land and roof tops gets whisked into stream. To prevent flooding, man needs to take care regarding concretizing a lot of land area. There should be enough land area to soak up water in the case of excess water coming on to the land areas. Flash floods are caused due to rapid urbanization and efforts need to be taken to curtail this in most areas.
Storm water drainage systems need improvement especially in drought prone areas. If there is soil available then flood water can seep faster into the soil leading to a lesser negative impact due to flooding. Many of the governments have taken measures like installing pumps, poldering, dams for flood mitigation, improvements in river bund channels, retention pond construction etc. Efforts are taken to manage the cycle of water as a whole. Care should also be taken that there is no excessive soil erosion due to human activities.