FLOODS IN INDIA: CAUSES AND CONTROL

Floods are natural disasters affecting the crops, livestock, infrastructure and floods a human beings Floods occur when water bodies like rivers carry more amount of water than their capacities and when this additional water cannot be drained in a proper manner. Floods are not a recent phenomenon; it has been occurring since ages. However, today the destruction caused by floods is immense because of creased population density and spread of people in every part of the country.

Types of Floods in India

Floods in India are not restricted to any one place. There are several different kinds of flood, and each one bears a different impact in terms of how it occurs, the damage it causes, and how it is forecasted. In this section we will discuss about the different types of floods.

• Coastal (Surge Flood) It occurs in areas that lie on the coast of a sea, ocean, or other large body of open water. It is typically the result of extreme tidal conditions caused by severe weather Eastern coast of India is vulnerable to this type of floods due to frequent cyclonic activities. Further, rising sea level due to climate change can put many coastal cities of the world at risk of being overrun by sea water.
• Fluvial (River Flood) It occurs when excessive rainfall over an extended period of time causes a river to exceed its capacity It can also be caused by heavy snow melt and glacial level outburst. The damage from a river flood can be widespread as the overflow affects smaller rivers downstream, often causing dams and dikes to break. This type of flood usually occurs in Himalayan rivers and cause massive destruction including landslides.
• Pluvial (Surface Flood) It is caused when heavy rainfall creates a flood event independent of an overflowing water body. It can happen in any urban area Apart from these, floods may also be caused due to upsurge in groundwater and even higher elevation areas that lies above coastal and river floodplains. burst of drain and sewer.

Major Flood Prone Areas of India

The major flood prone regions in India according to National Commission on Floods comprises of Ganga River basin which includes state of Uttar Pradesh, North Bihar and West Bengal. The heavy rainfall and huge siltation make flood yearly affair in Brahmaputra River system also. The inadequate surface drainage which causes inundation and water-logging over vast areas is the main cause of floods in North-Western part of India.

Cloudburst and torrential rainfall have caused flood in Uttarakhand and Kashmir. The small rivers of Kerala, originating in Western ghats and flowing to the Arabian sea, cause considerable damage when in spate. The deltaic region of the Mahanadi, the Godavari, the Krishna and the Kaveri suffer from occasional food owing to the large-scale silting and consequent change in the river course.

Cause of Flood

Floods are caused by natural, ecological or anthropogenic factors either individually or as a combined result Earthquake, landslide and cloudburst are among other natural causes of flood Man made causes include collapse of dams, embankments and efficient sewerage system in cities. The various causes of floods in India are Causes of Flood as follows:

• Rainfall of about 15cm or more in single day, sometimes are beyond the carrying capacity of the river causes the spilling of river over natural banks West coast f Western Ghats, Assam and Sub-Himalayan West Bengal and Indo-Gangetic plains faces flood due to heavy precipitation almost every year.
• The Himalayan rivers carry a lot of silt with them due to erosive action of the rivers. Because of the amount of silt carried by the rivers, the level of river bed rises and the water carrying capacity of the rivers gets reduced. This causes floods in the nearby areas of hill slopes. The water level in river rises because of greater run off Floods in Western ghats, Shiwaliks and Chotanagar plateau region occurs due to this reason.
• Excessive sand mining comes at a huge cost to the river and those living around it. Excessive sand mining can alter the river bed, force the river to change its course, erode banks and lead to flooding. It also destroys the habitat of aquatic animals and micro-organisms besides affecting groundwater recharge.
• In the flat terrain especially in plain areas, rivers have tendency to meander or change the course within a specific boundary. Because of this, frequent flood occurs in lower reaches of Ganga and Brahmaputra rivers.
• Tropical cyclone accompanied by strong winds, huge torrential rain and high tidal bores causes inundation of Eastern coastal regions of India. Floods due cyclone are common in the East coasts of Tamil Nadu, Andhra Pradesh, Odisha and West Bengal.
• In coastal areas sea rides deposit silt in the river mouths and discharge channels leading to steady deterioration of their discharge capacity, it causes floods in deltaic areas of India.
• Due to inadequate drainage, floods have occurred in Punjab, Haryana and Western UP After introduction of irrigation in these areas, the sub-soil water table rises fast leading to widespread flooding.

Control Measures

Being a natural phenomenon, the total elimination or control of floods is neither practically possible nor economically viable. Hence, flood control measures aim at providing a reasonable degree of protection against flood damage at economic costs in the section we will discuss various control measures of flood adopted by government and citizens.

• For controlling the flood, the government has constructed many dams and authorities which includes Damodar Valley Corporation for Damodar river, Narmada Control Authority for Narmada River, Hirakund dam on Mahanadi, Ukai dam on the Taps and the Bhakra dam across Sutlej. The Central Water Commission and National Flood Control Board in partnership with the National Disaster Management Authority (NDMA) has taken many steps for flood control.
• Among other structural measures, flood embankments, flood banks and levees have been constructed all along the major rivers, so that excess water in their channel does not cause havoc a nearby areas.
• Surface water drainage congestion due to inadequacy of natural or manmade drainage channels results in flooding in many areas in this regard government has started many drainage improvements programs.
• Diverting all or a part of the discharge into a natural or artificially constructed channel, lying within or in some cases outside the flood plains is a useful means of lowering water levels in the river to control the flood The flood spill channel skirting Srinagar city and the Supplementary Drain in Delhi are examples of diverting excess water to prevent flooding of the urbanized areas.
• Among the non-structural measures which strive to keep people away from flood waters, the flood-plain zoning and flood proofing have been adopted by the government. These are non-structural changes, adjustments or additions to reduce and prevent flood. Similarly, India Meteorological Department (IMD) issues flood forecasting and warning which are of immense help in relocation of the vulnerable section of population.
• Watershed management measures such as developing the vegetative cover i.e., afforestation and conservation of soil cover in conjunction with structural works like check dams, detention basins etc. serve as an effective measure in reducing flood peaks and controlling the suddenness of the runoff Government under National green mission aims at massive afforestation all along the channels of major rivers. Further many watershed developments projects have been taken up under MGNREGA, which will eventually help in controlling the flood.