ENVIRONMENTAL SCIENCE : POLLUTION AND ITS FACTORS 181
- Intensity of damage is governed by the time interval of standing floodwaters.
- High velocity of running water may uproot or weaken foundations of buildings.
- Rate of rise and discharge of a river is important as a basis for flood control.
- Frequency of occurrence estimated over a length of period would determine the
kind of activities the flood plain should be put to. - Generally the rainy season is characterized by the floods during which agricultural
economy suffers a huge loss.
Effects of Floods
- Rising water, erosion and the force damages the residential and commercial building.
They are dangerous for villages lying in the coastal areas as it sweeps away
everything, which comes into its path. In mountainous areas it is the chief cause
of landslides. - Fisherman, local people, cattle, animals and vegetation suffer a great loss of life
and property. Most of the deaths are reported to be from drowning. - Fresh water supplies by all sources are nearly destroyed and contaminated hence
the areas falling under its impact bear a great risk of suffering from water borne
diseases. - The destruction of food and fodder crops result in acute food shortage.
- Floods also make soil infertile, as the topsoil is lost due to erosional activity.
- Floods are also known to preserve, wetlands and recharge ground water.
Flood Control
- Depth and width of the riverbed could be increased as its capacity to carry larger
loads increases manifold and thus reduce the area of the flood plain. - A network of canals can be established from the river systems, which generally
leads to floods. This would also benefit the agricultural economy/ section. Care
must be taken in the design and construction because of the possible environmental
impact and necessary safety features. - Reservoirs should be made for storing floodwater and releasing them at manageable
rates. This would require careful engineering. Dams, and reservoirs would further
lead to generation of resources. - Newly constructed residential as well commercial buildings should have foundations,
which are strong enough to respond to flood conditions. - Rivers and streambeds should be stabilized with stone, masonry or vegetation at
the banks. This should strictly be followed where rivers pass through cities, specially
near bridges.
Post Disaster Requirements
The initial response to flooding authorities/community should include:
Search and Rescue operations, water provision,
Medical assistance, Disaster epidemiological surveillance assessment, food and
and temporary shelter.