Andhra Pradesh is exposed to cyclones, storm surges, floods and droughts. A moderate to severe intensity cyclone can be expected to make landfall every two to three years. About 44 percent of the state is vulnerable to tropical storms and related hazards.
In India, the cyclones develop in the pre-monsoon (April to May) and post-monsoon seasons (October to December), but most of them tend to form in the month of November.
Cyclones on the east coast originate in the Bay of Bengal, the Andaman Sea or the South China Sea, and usually reach the coastline of Tamil Nadu, Andhra Pradesh, Orissa and West Bengal, which are the most vulnerable to these types of hazards. Two of the deadliest cyclones of this century, with fatalities of about 10,000 people in each case, took place in Orissa and Andhra Pradesh during October 1971 and November 1977 respectively. The super cyclone of Orissa in 1999 caused large scale damage to life and property.
Along the Andhra coast, the section between Nizampatnam and Machilipatnam is the most prone to storm surges. Vulnerability to storm surges is not uniform along Indian coasts. The following segments of the east coast of India are most vulnerable to high surges
1. North Orissa, and West Bengal coasts.
2. Andhra Pradesh coast between Ongole and Machilipatnam.
3. Tamil Nadu coast, south of Nagapatnam.
The states bordering the Arabian Sea on the west coast are not completely safe either, as Kerala, Gujarat - and to a lesser extent Maharashtra - are also prone to cyclones. With a frequency of four cyclones per year, one of which usually becomes severe, the Bay of Bengal accounts for seven percent of the annual tropical cyclone activity worldwide.
Despite this relatively low percentage, the level of human and property loss that cyclones cause around the Bay is very high. Once the cyclones enter the mainland, they give way to heavy rains which often translate into floods, as it was the case with the damaging cyclone-induced floods in the Godavari delta, in August of 1986.
Many drought prone areas adjacent to coastal districts in eastern maritime states are thus vulnerable to flash floods originated by the torrential rains induced by the cyclonic depression. In addition to cyclones and its related hazards, monsoon depressions over the north and central areas of the Bay of Bengal move until reaching north and central India, including portions of Andhra Pradesh, bringing heavy to very heavy rains and causing floods in the inland rivers between June and September.
In Andhra traditionally, the flood problem had been confined to the flooding of smaller rivers. But the drainage problem in the coastal delta zones has worsened, multiplying the destructive potential of cyclones and increasing flood hazards. A critical factor is maintenance of irrigation systems. On several occasions, deaths have been caused by breaches in tanks and canals as well as over-flooding caused by silting and growth of weeds.
Effect of Repeated Disasters
The regular occurrence of Disasters both Natural and Man made in Coastal Andhra Pradesh in India has had a series of repercussions on the state country’s Economy, its development policies and political equilibrium and daily life of millions of Indians.
Andhra Pradesh is battered by every kind of natural disaster: cyclones, floods, earthquakes and drought. The coastal region suffers repeated cyclones and floods. The 1977 cyclone and tidal wave, which resulted in great loss of life, attracted the attention of the central and state Governments of India and the international donor communities, as did those of 1979, 1990 and 1996. The floods in the Godavari and Krishna Rivers caused havoc in the East and West Godavari and Krishna districts.
Earthquakes in the recent past have occurred along and off the Andhra Pradesh coast and in regions in the Godavari river valley. Mild tremors have also hit the capital city of Hyderabad, for example in September 2000.
Social and economic life of AP's population is characterized by recurring natural disasters. The state is exposed to cyclones, storm surges, floods, and droughts. According to the available disaster inventories, AP is the state that has suffered the most from the adverse effects of severe cyclones. It has been estimated that about 44 percent of AP's total territory is vulnerable to tropical storms and related hazards, while its coastal belt is likely to be the most vulnerable region in India to these natural phenomena. Khamman district, in the Telengana region, is affected by monsoon floods, along with five districts in Coastal AP. Four districts in Rayalaseema and five in Telengana experience drought. Along the coastline, the section between Nizampatnam and Machilipatnam is the most prone to storm surges. The fertile Delta areas of the Godavari and the Krishna rivers, which contribute substantially to the state's economic prosperity, face flood and drainage problems, and more so in the aftermath of cyclones.
More than sixty cyclones have affected AP this century. The incidence of cyclones seems to have increased in the past decades, to the extent that severe cyclones have become a common event occurring every two to three years, repeatedly and severely affecting the state's economy while challenging its financial and institutional resources3. Almost2 9 million people are vulnerable to cyclones and their effects in Coastal AP, 3.3 million of who belong to communities located within five km of the seashore. The deadliest cyclone in the last twenty years took place in November 1977 killing about 10,000 people. More recently, the May 1990 cyclone, with a death toll close to 1,000 people, caused about US$1.25 billion in damage in ten districts, including the entire coast. Between 1977 and 1992, about 13,000 lives and 338,000 cattle were lost due to cyclones and floods, and nearly 3.3 million houses damaged.
May cyclones are relatively rare in the region, and only about 13 have affected AP in this month this century. However, when they badly hit the Delta areas, as it happened in 1979 in the Krishna district - where 80 percent of the casualties occurred - the population in danger may be higher than usual. May is rice harvesting season, and a good number of itinerant laborers come to the delta from less fertile areas of AP in search of work. Since they lack awareness of the area's most prevalent hazards, this migrant population is more vulnerable than the permanent delta residents. Similarly, entire families have come to the delta districts to engage in activities related to shrimp farming, which has taken off recently in the area. They are involved in the collection of fingerlings, living for several months a year in makeshift shelters along the marshes. The warnings may not reach them on time, and even when they do, their inexperience renders them highly vulnerable.
The Godavari and the Krishna rivers have well-defined stable courses, and their natural and man-made banks have usually been capable of carrying flood discharges, with the exception of their delta areas. Traditionally, the flood problem in AP had been confined o the spilling of smaller rivers and the submersion of marginal areas surrounding Kolleru Lake. However, the drainage problem in the delta zones of the coastal districts has worsened, thereby multiplying the destructive potential of cyclones and increasing flood hazards. Moreover, when a storm surge develops, as it was the case during the severe November 1977, May 1990 and November 1996 cyclones, threats to humans and property multiply as the sea water may inundate coastal areas which are already being subjected to torrential rains. Finally, a critical additional factor affecting the flood management and the irrigation systems is the lack of maintenance. On several occasions, such as the May 1979 cyclone, most of the deaths were occasioned by breaches to the chains of tanks and canals, and over-flooding due in part to the choking of drains by silting and growth of weeds.
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