Cloud seeding is the amazing technology and process by which additional rain is artificially produced from a cloud. For those parts of the world where rain and water is less reliable and more valuable, this technology can potentially bring great benefit to environmental, agricultural, tourism and sustainable energy industries.
Although Cloud seeding has huge potential benefits, this new technology is yet to reach its full potential. We investigate, along with two experts who have agreed to share their opinions with Ask The Experts.
Vadim Sablo speaks to Professor T. Shivaji Rao, director of The Centre for Environmental Studies at GITAM University who has been writing articles on cloud seeding since 1985 and Professor Steve Siems, who is involved with the Science Advisory Group for the Queensland Cloud Seeding Research Programme. VS- Hello, could you please describe briefly how cloud seeding technology works? TSR- Clouds contain water droplets and often a few ice crystals. Cloud seeding technology is based on the assumption that due to deficiency of sufficient nuclei, the clouds part with only 10% of their water content as rainfall or snowfall while the remaining moisture gets wasted away. In this case we inject chemicals to squeeze more precipitation from such clouds in which minute cloud droplets are converted into large raindrops or snowflakes, which fall on earth due to gravity.
Clouds whose tops do not reach freezing temperatures in the sky are known as "Warm clouds'"and those that extend into freezing levels upto about 13 km.into the sky are "Cold clouds"Warm clouds are seeded with hygroscopic chemicals like sodium or calcium chloride Etc.,while cold clouds are seeded with 'ice particles' or "Silver iodide particles"Etc., 3]Cloud seeding is done to definitely reduce the impacts of Climate Change as can be seen by the latest scientific article under the web site:http://www.hindu.com/2010/07/22/stories/2010072265102200.htm SS- Classic "glaciogenic" cloud seeding is the process of introducing ice nuclei (silver iodide) into clouds composed of super cooled liquid water droplets. These droplets will then rapidly freeze into crystals and the ice will grow quickly into precipitation.
VS- What are the main benefits of cloud seeding? TSR- Enlightened scientists, bureaucrats, industrialists and statesmen in about 50 countries have been using cloud seeding operations for over 40 years for various purposes like:
1. Increase of annual rainfall for drinking and agricultural purposes
2. Dispersal of fog in airports and metropolitan city roads
3. Increase of hydropower generation at the cheapest cost
4. Suppression of hail storms to reduce damage to life, crops and properties
5. Mitigation of devastating impacts of recurring droughts
6. Mitigation of damaging impacts of global warming and summer temperatures
7. Increase of annual rainfall for improving the forests, wildlife and the environment VS- Will we be able to reduce pollution and control climate change with this technology? SS- No. The process of enhancing rainfall on a small regional scale is vastly different than influencing climate change - a global phenomenon. Similarly, there's no real hope of using this approach to change local air pollution. We aren't sure why cloud seeding appears to be working so well in Tasmania, when it has failed to produce clear results in other parts of the world. It may, in part, be because the clouds are so pristine, coming off the Southern Ocean. If so, local air pollution may inhibit this glaciogenic approach. TSR- Cloud Seeding could be useful in reducing the dust and gaseous pollutants floating in the air. It is done in China to clean the dust-laden air by the snowfall and the rainfall, which also help in cleaning the leaf surfaces plants and external faces of buildings and monuments coated with dusty air. The precipitation caused by cloud seeding adds more water to the annual flows in the rivers and their tributaries and thereby dilutes the concentration of pollutants in the flowing water to enhance their self-purification capacity. Similarly addition of water into ponds and lakes helps in dilution of pollutants and thereby make the waters useful for secondary purposes. Even ground water gets its pollution levels diluted due to augmentation of water resources by cloud seeding. Since additional water promotes tree growth and thereby the atmosphere becomes cooler the impacts of climate change can be slightly reduced. VS-Where and how is cloud seeding used in the World? TSR- Cloud seeding is used in about 40 countries in the world. It is used to augment water resources in rivers and lakes and to improve ground water resources. Cloud seeding is done in Snowy Mountains of Australia to augment snowfall to promote tourist trade. Cloud seeding is done in Tasmania to augment hydro-electricity production at cost benefit of 1:30. In China and Russia cloud seeding is done to provide clear skies during festive occasions like the Olympic Games and other annual celebrations. VS- Is cloud seeding commercially interesting (farming, tourism etc.), or does it represent greater interest for governments? SS- Here in Australia, it's commercially driven. Hydroelectric companies seek to increase rainfall into their damns and produce more electricity. Given the drought, I would think the government would be more interested, but there was a long history of government support for this in Australia. TSR- Cloud seeding is commercially useful for agricultural operations, augmentation of Municipal water supplies and hydro-power generation, ground water replenishment and promotion of tourist trade in sky resorts. Cloud seeding is used in some cities in USA for removing fog, which interferes with traffic in the aerodromes, metropolitan city roads. Some countries like USA use cloud seeding for quenching forest fires. In view of the economic importance of additional precipitation many countries are resorting to cloud seeding operations on a large scale. VS- There are fears of toxicity and possible soil contamination, which may be caused by cloud seeding, is it true? What does the science say? TSR- Research investigations on the damaging impacts of chemicals used for cloud seeding indicated no perceptible damage to public health and the environment. Since the seeding materials used for the operations are very small in quantity their presence in the precipitation has been detected to be very low in concentration. Concentration of silver is much below its US Public health Standard of 50 micro-grams per litre. In the case of iodine, its presence in the rainwater sample collected at the end of cloud seeding operations is found to be far lower in concentration than that found in the common iodized table salt used by the people. VS- What about the effectiveness of this technology, some say it is unclear whether it really works. SS- I respect that argument. Indeed, I suspect it is true for most parts of the world. Tasmania may just be special because of the pristine Southern Ocean. But in Tasmania we've had two positive field experiments and now 45 years of seeding to get some statistically significant results. TSR- Cloud seeding experiments were being conducted in about 40 to 50 countries for more than 4 to 5 decades. On the average the benefits are estimated at about 20 times the cost incurred for the operations. After reviewing the results of cloud seeding operations for several years the world Meteorological Organization (WMO), American Meteorological Society (AMS) and the Weather Modification Association (WMA) issued statements indicating 5% to 20% additional rainfall from clouds over the continents and 30% from the maritime clouds. It was further stated that the hail suppression experiments caused reduction of 20% to 50% in the costs of damage due to hailstorms. VS- There are also opinions that cloud seeding can increase rainfall in one territory at the expense of another, is it true? TSR- This usual question of whether cloud seeding “robs Peter to pay Paul” must be answered with an emphatic “no”. The cloud seeding in one place does not cause any perceptible reduction in rainfall that normally occurs in the neighbouring areas. Out of the total atmospheric moisture continuously flowing over any region the normal condensation removes about 20% of the total moisture to form into clouds. Cloud seeding causes additional precipitation although a cloud normally gives 20% of its moisture as rainfall. Further artificial rain making by cloud seeding causes additional precipitation of 20%. So 100 (0.20 x 0.20 x0.20)=0.8% of the water vapour is removed. VS- Does this technology have a future, if yes where will it be widely used? SS: In the present form, it has a limited future. However it's possible that modifications can make cloud seeding more effective and viable in other locations. VS- What are the major steps to overcome today to make this technology really useful and widely developed? TSR- Cloud seeding is opposed by some scientists, bureaucrats and politicians due to lack of sufficient level of awareness about the subject. Sometimes scientists may pursue their own interests and development of technology such as cloud seeding suffers. In order to overcome the opposition from such vested interest among scientists, bureaucrats and politicians who live at the expense of public sufferings we have to create large scale awareness among the school, college and the university students, Government Officials and general public on the scientific foundations, technological feasibility, economic viability and social acceptability of cloud seeding operations for promoting public health, environmental resources, National economy and sustainable development. SS- One of the aims should be getting cloud seeding work in more marginal conditions. This may require a lot more insight and a rethink of the basic concepts and approaches. VS- Prof. T. Shivaji and Prof. Siems, thank you very much for your contributions to this article.
For further details browse through the following websites:
Why do most of the clouds move from south to north direction
over our subcontinent?
MAHESHKUMAR T.,
Mulanur, Tamil Nadu
Clouds usually move according to the wind pattern. Wind is
caused due to difference in temperatures and pressures which may be affected by
various factors. Movement of wind is a very complex phenomenon affected by
latitude, proximity of water bodies, sea shore and land undulations. It is also
affected by the rotation of the Earth.
Wind blows from points of high pressures to low pressure
points. Wind caused due to difference in temperatures is known as convection
current. Wind moves from warmer regions near the Earth surface to higher up
colder regions. Where the land mass is surrounded by sea water, air near land
surface is warmer and moves up. To replace the air mass, wind blows from sea to
the land mass. This is also known as breeze. Then there is global movement of
wind.
Earth regions near the equator get maximum heat energy from
the sun. This causes air to rise up vertically near the equator. To replace,
cold wind blows from higher latitude regions. There are also seasonal variations
in the direction of wind due to tilt of the Earth, which further makes the
phenomenon more complex.
In our subcontinent, the southern regions are surrounded by
sea water which causes the wind to move from sea to the land mass i.e. from
south to north. The direction changes as the seasons change.
The author has taken the Bachelors Degree in Civil Engineering from Andhra University College of Engineering at Kakinada in the first batch (1950). He has worked as Assistant Engineer from 1950 onwards in the Central and State Governments upto 1989. When he Retired as Engineer-in-Chief of Irrigation projects, Government of Andhra Pradesh. In addition to experience in field investigation, planning, design, research and water management in irrigation projects, the author had field experience in the construction of Rallapadu Project, Hirakud Dam (Orissa), Nagarjunasagar Dam, Mid Pennar Dam, Tungabhadra High Level Canal, Uravakonda Deep Cut, Kalyani Dam, Sriram Sagar Dam, Telugu Ganga Project (Noted in the order of his Service from 1950 to 1989). His later field experience in irrigation projects till 2006 was in the African countries, during his assignments with the World Bank and in the Asian Countries during his assignments with the United Nations (O.P.S.)
At present there was a controversy on holding public hearing for embankments project estimated at Rs.700 crores as a supplementary project of the Polavaram dam. The AP Chief Minister is declaring that AP State cannot hold this public hearing for their Polavaram project in Orissa and Chattisgarh. The Orissa and Chattisgarh state Governments are refusing to hold public hearing on this project because they have filed cases in the supreme Court against the Polavaram dam and hence it may be subjudice. But the Central Government Ministry of Environment and Forest issued a notice to the AP State Government why they are going ahead with the Polavaram dam project without holding public hearings on the embankments project in Orissa and Chattisgarh. In the normal conditions the AP State Government should have maintained cordial relations with Orissa and Chattisgarh on this project for securing their approval for the main dam project and also this supplementary embankments project. Similarly they require the consent of these upper states even for the 960 MW hydro-power project which is part of the Polavaram dam project. Now the AP State Government has taken a posture of confrontation with the upper states and is demanding the Union Government to use its good offices to convince the upper states to the construction of Polvaram dam project estimated at Rs.16,000 crores.
1. Environmental clearance for Forests given by Union Ministry is self defeating:
Catch-22 situation is created by the Union Ministry of Environment and Forests by according clearance for 3700 ha. of forest land for Polavaram Dam.This is a meaningless as well as a mischievous action taken by the Government . Even the Orissa High Court Judgement of April 2006 directs the AP State Government to go ahead with Polavaram project without causing any submersion of villages, forest lands and displacement of tribals in Orissa. This judgement is like the judgement in the Shakespearean drama of Merchant of Venice where the judge asks the plaintiff a Jewis money lender, Mr.Shylock to take his pound of flesh from the chest of the defendant merchant who failed to repay the debt in time. This judgement directs Shylock to cut his pound of flesh without a drop of blood, it means a Catch-22 situation, or a self-defeating course of action: or a paradoxical condition or set of circumstances that preclude any attempt to achieve the goal without getting engulfed by the disabling conditions. you cannot have your pound of flesh without a drop of blood. One cannot have the cake and eat it too. Hence the action of the Central Government Ministries in giving clearances to Polavaram project is an act of cheating the people of India at a time when the people, state officials and other experts have to protect the Environment under Article 51 A(g) of the constitution of India.
2. Environmental clearance given by Union Ministry of Environment in October 2005 is based on insufficient and false information provided in the EIA report by AP State :
According to the Environmental Protection Act 1986 and its regulations the AP State Government engineers, officials of Ministries like Finance, Environment and Forests and Pollution Control Board are expected to know that the Environmental Impact Assessment(EIA) Report for Polavaram must contain not only Risk Analysis (RA) and Dam Break Analysis (DBA) reports but also the Emergency Action Plan (EAP)and Environmental management plan[EMP] reports in detail so that the costs of remedial actions to be taken in case of a potential dam burst will have to be included in the original project budget so that the genuine cost benefit ratio can be scientifically deduced on the basis of the alternate project proposals which confer the similar economic benefits as contemplated by the original project. Similarly the various expert committee members of various Ministries in the Union Government like Finance, Agriculture, Water Resources, Planning Commission, Central Water Commission, environment and Forest and Tribal Affairs must also scrutinise the EIA report including RA, DBA,EAP and EMP reports.
Unfortunately due to lack of accountability among all the concerned engineers, Secretaries and officials of the AP State and Union Government Ministries most of the permissions for Polavaram dam project were sanctioned blindly with the result that the people of Andhra Pradesh were mislead by both the Union Government officials as well as state Government officials on the safety, economics and sustainable development aspects of the project. Hence people in the state are looking at the project just as the traditional blind men looked at the elephant in the old Chinese story. Today the people in Malkangiri disrict of Orissa are agitating against the Polavaram project on the ground that the damaging impacts of this project will be felt in 18 villages including displacement of more than 20,000 people, mostly tribals and more than 1.5 lakh acres of forest lands to be inundated due to the proposed Polavaram dam. The Orissa people are questioning the Central Government Why the Union government Ministries have blindly given permissions for an interstate projects like Polavaram without taking into consideration the views of the neighbouring states of Orissa and Chattisgarh as per rules and regulations.
The dam break analysis reports prepared for Polavaram dam by the AP State Government and scrutinised by several Ministries of the Union Government are blind to realise the damaging impacts such as providing watery grave to 50 lakhs of people downstream of the dam in case of an inevitable collapse of the dam for several reasons and the consequential economic loss of more than 1 lakh crores of rupees which makes the country poorer and thereby promotes poverty on a large scale including promotion of unemployment and inflation which are not certainly the main objectives of the proposed project. The people of India have a right to life, right to health, right to employment and all these rights are going to be adversely affected by this dam.
Moreover EIA report was prepared on the basis of the Probable Maximum Flood of 36 lakh cusecs which is a serious underestimate for a massive catchment area of a major river like Godavari. In view of the enormous floods received in Godavari in August 2006 the Central Water Commission opened their eyes and made realistic calculations for estimating the Probable Maximum Flood and placed it at 49.5 lakh cusecs or 50 lakh cusecs. Since the Environmental clearance for the project was already obtained based on 36 lakh cusecs flood the calculations made for dam break analysis and for demarcation of backwater levels for identifying the areas of submersion in the upstream of the dam will be highly unrealistic and consequently the estimated cost of the project would be underestimated.
3. Legal methods of decision making for Environmental clearances for major project:
(a) Precautionary principle : Whenever legal judgments are to be pronounced on the acceptability or rejection of any development projects including irrigation projects an environmental impact assessment including the social impact assessments have to be made and if there are grey areas regarding the environmental backlashes on crucial natural resources conservation including species of plants, animals and human beings a decision has to be based on the precautionary principle which has been accepted by the world nations at the Rio-De-Janeiro conference on Human environment (1992). One of the reputed Judges of the Supreme court of New South Wales, Australia , Justice Paul Stein gave his considered opinion on how to take decisions on projects intended for sustainable development. (Quoted from Environmental Law Review Journal of UK Volume-2, 2000)
Use Of The Precautionary Principle For Development Projects
Principle 15 of the Rio Declaration states:
“In order to protect the environment, the precautionary approach shall be widely applied by states according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation”.
In the Australian context definition adopted in legislation has been:
“Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation. In the application of the precautionary principle, public and private decisions should be guided by:
(i) careful evaluation to avoid, wherever practicable, serious or irreversible damage to theenvironment; and
(ii) an assessment of the risk-weighted consequences of various options”.
The precautionary principle has the potential for positive gains for the environment and national development if applied appropriately by decision-makers. Along with the principles of ecologically sustainable development (ESD), this principle has the capacity to be a key tool for environmental protection and even improvement. The converse of the non-application of this precautionary principle, where the circumstances demand it, can surely lead to an irreversible deterioration in the environment and loss of ecosystems and human environmental assets.
To deal with some cases of application of this principle we can quote the “ Pakistani case of Zia v WAPDA in which the State Authority was constructing an electrical grid station in a residential area. The petitioners, local residents alleged that the electromagnetic field created by the high voltage transmission lines would pose a serious health hazard. Article 9 of the Pakistani Constitution states that ‘no person shall be deprived of life or liberty save in accordance with law’. Article 14 of the constitution provides that ‘the dignity of man and the privacy of the home shall be inviolable’. Article 184(3) provides for public interest litigation. Where the ‘life’ of citizens is degraded, the quality of life is adversely affected and health hazards are created, affecting a large number of people, the Supreme Court may grant relief to the extent of issuing injunctions on factories which create and promote environmental degradation. The Court held that existing scientific evidence regarding the possibility of adverse biological effects on people from exposure, as well as the possibility of reducing or eliminating such effects, was inconclusive. In responding to such scientific uncertainty the Court applied the precautionary principle for the benefit of the public.
In another case of Andhra Pradesh Pollution Control Board v Nayudu, the Supreme Court of India considered a petition claiming that certain hazardous industries proposed to be established without the necessary certificate from the Pollution Control Board could not proceed to operate such polluting industries . M. Jagannadha Rao J elaborated the difficulties faced by environmental courts in dealing with scientific data. He quoted articles by Lords Woolf and Carnworth on the desirability of specialist environmental courts. In particular, his Honour discussed the status and application of the precautionary principle.
His Honour said:
“The ‘uncertainty’ of scientific proof and its changing frontiers from time to time has led to great changes in environment concepts during the period between the Stockholm Conference of 1972 and the Rio Conference of 1992. In Vellore Citizens’ Welfare Forum v Union of India and others, 1995 (5) SCC 647, a three Judge Bench of this Court referred to these changes, to the ‘precautionary principle’ and the new concept of ‘burden of proof’ in environmental matters.”
Kuldip Singh J after quoting the principles evolved in various international Conferences and to the concept of ‘Sustainable Development’, asserted that the Precautionary Principle, the Polluter-Pays Principle and the special concept of Onus of Proof have now emerged and govern the law in India too, as is clear from Articles 47, 48-A and 51-A(g) of Indian Constitution . . .
The Court also elaborated on the issue of burden of proof in cases involving the application of the precautionary principle: “ The precautionary principle suggested that where there is an identifiable risk of serious or irreversible harm, including, for example, extinction of species, widespread toxic pollution in major threats to essential ecological processes, it may be appropriate to place the burden of proof on the person or entity proposing the activity that is potentially harmful to the environment.”
Freestone, Legal Expert of the World Bank recognizes the emergence of the precautionary principle as one of the most important developments of the new era. The precautionary principle has become part of international customary law. How the rhetoric of the principle can be operationalised is one of the challenges for the first decade of the 21st century. This precautionary principle is not absolute nor extreme in its scope. It does not halt development until the science is clear. But it changes the underlying presumption from freedom of exploitation to one of conservation. One thing is clear—the precautionary principle is here to stay, with or without legislative support. However Decision-makers and courts will not be able to avoid it or merely pay lip-service to it. Surely the courts will be required to review its application and attempt to apply it. Courts have to evaluate the principle and its place in environmental decision-making and particularly with regard to major irrigation projects whose viability is questioned in public interest.
In the Polavaram project the scientific and technical experts of the Union Ministry of Water Resources located in the National Institute of Hydrology, Roorkee clearly stated in their report that several dams have collapsed and if the proposed earth and rockfill dam at Polavaram were to fail for one reason or the other the consequential wall of flood water will wipe out of existing thousands of people living downstream of the dam. Hence there is sufficient scientific proof and the precautionary principle has to be applied in this case and alternate methods of achieving the same economic goals can be obtained by converting the killer Polavaram dam into multiple barrages which are safe and beneficial.
(b) Law of Comparative Consequences: In the United States whenever there is a conflict in decision making with regard to a major development projects a comprehensive environmental impact analysis report is prepared including emergency response systems and disaster management systems. After considering the advantages and disadvantages of the proposed project a decision is ultimately taken on the basis of the law of comparative consequences. If expert “X” presents a particular view that the positive contributions of the project work out to certain amount of costs and expert “Y” presents another view involving the disastrous consequence of the project resulting in negative impacts of the project amounting to certain amount of costs, then the decision makers will consider both points of view. The decision makers compare the relative costs of implementation of the project and non-implementation of project and ultimately decide on the choice which presents least cost to the community. Otherwise a modified project which can achieve more or less the same economic goals of development will be taken up in the interests of ensuring sustainable development of the community on the plea that development also forms part of the Right to life and Right to livelihood as the project not only provides employment potential but also secures economic and social development resulting in a better quality of life. In this context the people of India in general and the people of Andhra Pradesh in particular must weigh the costs and benefits of the proposals made by the State Government for construction of Polavaram dam and alternate proposals of constructing multiple barrages in place of the dam.
4. Union Ministry of Environment shall reject clearance for Polavaram dam project because Embankments intended for flood control are inevitably bound to fail :
By furnishing wrong information and without conducting public hearing on the EIA report in the areas likely to be submerged in Motu and Konta taluks of Orissa and Chattisgarh, the Environmental clearance obtained cannot be strictly considered to be legal. Further the AP State Government submitted a second EIA report estimated at Rs.700 crores for construction of embankments to protect the areas likely to be submerged in the Sileru and Sabari catchments in Orissa for a length of about 30km and even for this project also there was no public hearing conducted in the upper states and the state Government has not taken the consents of the upper states for construction of these embankments. Thus the clearances taken for this project from the various Ministries of the Union Government such as Water Resources, and Tribal Affairs and Planning Commission are based upon a misleading and incomplete environmental clearance obtained from the Union Ministry of Environment.
Embankment dams can also fail due to Bombing by terrorist agencies or enemy countries as Britishers dropped Bombs over the German dams and destoyed them to cause damages to the people and properties
see the web site for more details on Bombing over Dams: http://en.wikipedia.org/wiki/Operation_Chastise
(a) False view of Government agencies on Embankments to protect people from floods:The contention of the Central Water commission that the lands in Chattisgarh and Orissa can be protected from the floods due to Polavaram dam construction is based on false assumptions.
The Central Water Commission is misleading the courts and the state and central Governments that submersion of lands in the Sabari river basin and Sileru river basins in Chattisgarh and Orissa can be protected by Andhra Pradesh by constructing embankments along the river courses. This false assurance to the states and the Bachawat Tribunal was also based upon the immature views of the Central Water Commission and the Union Ministry of Water Resources provided during the time of the interstate agreement on Polavaram project in April 1980.
In fact the embankments constructed by the AP State Government along the banks of the Krishna river to protect the temple town of Alampur in Mahaboobnagar district have miserably failed to prevent the peak floods that ravaged havoc during October, 2009. Flood embankments have miserably failed to protect the people and their properties in several river basins since a number of years in the states of Bihar, Uttar Pradesh, Orissa and Bangladesh. The evidence of such failures can be found from the following websites.
The former secretary for the Union Ministry of Water Resources and an International expert on Water Resources management clearly establishes that embankments cannot ensure safety of people and their properties from serious floods in the rivers and for several reasons they cause more misery to the people. The following is an extract of his article on the failure of flood embankments.
(b) Expert views on failure of embankments to control floods in rivers :
The following are the views of the Water Resources expert Sri.RAMASWAMY IYER, Former Secretary, Union Ministry of Water Resources, Govt. of India, on the futility of embankments to protect people and their properties from floods.
“From time to time there are floods in various parts of this country, and sometimes they are very heavy and cause much loss of life, livelihoods and property. Whenever this happens, it generates a strong feeling that something should be done about this problem. Starting from the proposition that the problem, i e, floods, should not be allowed to happen again, administrators and engineers decide that the river needs to be controlled, and come up with proposals for embankments and dams. Is there anything wrong in that reasoning? To answer that question, we must first distinguish between avoidable and unavoidable floods. When Delhi or Mumbai gets heavily flooded with the first monsoon showers, the cause is inadequate or badly designed or poorly maintained or carelessly blocked drainage systems, or the ill-considered diversion of natural drainage channels. These are floods caused by human error or failure or negligence or folly, and are entirely avoidable.
Floods are also sometimes caused by bad dam management, and these too are manmade. The Orissa floods of September 2008 seem to fall into this category. When we describe a flood as man-made, the
implication is that appropriate measures at an earlier stage could have averted or minimised the flood.
That does not apply to periodical river floods. These are natural phenomena arising from various factors. There could be seasonal floods because of heavy and continuous rains in the monsoon period; flash floods from cloud-bursts; floods resulting from the sudden release of waters held up by blockages caused by landslides in the mountains; and so on. These floods cannot be prevented. They have occurred before and will occur again. They can be of varying magnitudes and intensities, and the regular floods, i e, those other than freak events, are classified by probability of recurrence (once in 20 or 100 or 1,000 or 10,000 years). When the flood-waters come, the river needs space to spread and accommodate them. That space is known as the natural flood-plain of the river. If we occupy the flood-plain or build structures on it, or try to jacket the river within narrow confines, we are asking for trouble.
Embankments: Wrong Thinking If habitations or structures or activities have already – unwisely – come up in areas that are likely to be flooded, and the option of moving them to other areas is not available, some degree of protection through bunds or embankments may be inescapable. However, it seems clear that wisdom lies in avoiding such situations. Generally speaking, it is preferable to let the river flow and have its space, and refrain from constraining it through embankments. There are many reasons for that statement. Assuming that an embankment is properly maintained – a questionable assumption – it might still give way in an exceptionally heavy flood. That is the nature of embankments. Embankments tend to fail and have to be rebuilt repeatedly at enormous cost, often a multiple of the
original cost of building them. Even if they do not break down, they might still cause various problems. The engineering assumption in the Kosi case and elsewhere was that the jacketing of the river would increase the velocity of the waters leading to a scouring of the river-bed, and that the river would find extra space for itself.
Experience has not borne out that assumption. The jacketed river might proceed to attack areas further downstream. The embankment that prevents the river from spreading also blocks drainage from either
side into the river, leading to the emergence of water logging and even flooding in the areas “protected” by the embankment (as already mentioned). Sluices are no answer because the deposition of silt leads to a rise in the level of the river-bed, with the river flowing above the level of the ground on either side: instead of waters from outside flowing into the river through the sluices, the river waters will tend to flow out. While it might be possible to cite some specific instances in which embankments have done some good without doing much harm, they are in many cases remedies worse than the disease.”
5. Polavaram dam is bound to collapse due to several reasons:
Several people think that dams do not fail as they do not know that storage of water behind any dam is a source of hazard of some magnitude depending upon the amount of water stored and the type of structure used for storage. Several people consider that since the Nagarjuna Sagar dam and Srisailam dam have not failed during the peak floods of 26.5 lakh cusecs in Krishna river that occurred in October 2009 the Polavaram dam also would not fail. This is a wrong concept because the Nagarjuna Sagar dam is a massonary dam and the Srisailam dam is a concrete dam while the proposed Polvaram dam is an earth and rockfill dam
(a) Earthen dams have more chances to collapse due to several reasons:
It is good to start construction of Polavaram earthen dam with a firm conviction that it would be built very strongly and would never break due to any quality reasons. If. the recent experiences on the earthen dam constructed in the State are any guide, one cannot be so sure of this conviction. In fact, all the earth dams will be constructed only with such convictions. But, we see different results all over the world. The Earthen dams of two medium irrigation projects (namely Gundlavagu Project and Palem Vagu Project,) constructed during the past four years in the State, have breached even without the designed maximum flood occurring. During August.2010 the Subbareddy Sagar Medium Irrigation project in Prattipadu Mandal of East Godavari district collapsed due to excessive floods after 12 years of its construction.
Kadem dam in Godavari basin also collapsed in 1958. There are innumerable similar examples of dam breaks throughout the world, especially with earthen dams, well before the occurrence of P.M.F. The recent one in India was the Morvi Earth Dam (Gujarat) breach, which killed about 15,000 people. Earthen dams can also break due to reasons other than quality. That is why the recent international recommendation is to avoid, construction of earthen dams in the close vicinity of thickly populated areas. Polavaram earthen dam sits just upstream of an extremely thick populated area. Even though the Polavaram earthen dam is designed for a P.M.F. of 50 lakh cusecs, the possibility of dam break cannot be ruled out (vide UN & ICOLD Guidelines on E.I.A.). Infact several dams failed in India and the details are presented in the Annexed table below.
(b) Why Polavaram dam is bound to collapse while the barrages project will be safe:
There is an argument that when a flood of 89 lakh cusecs occurs in the river, the areas on either side of the Godavari river will any way get flooded (with or without the dam), and the population will get effected, since the protective flood banks are designed only for a maximum discharge of 36 lakh cusecs. But, there is a difference between a dam break and a natural flood increase. In the case of a Polavaram dam break, the stored water of 194 TMC along with the huge flood of 89 lakh cusecs will flow down below, as a gigantic wave, similar to the Tsunami wave. People will have no time to leave their habitats. If such a break occurs during the nights, 46.15 lakh people will have a watery grave within some hours of occurring of the dam break. With regard to a natural occurrence of 89 lakh cusecs, this would occur gradually over a number of days and people will have time to observe the same, vacate their habitations, and move to the designated higher grounds. It has happened similarly in Krishna Delta during the extraordinary floods that occurred in Krishna river in October, 2009. In other words the increase in water levels does not happen suddenly in a few hours (unlike the dam burst wave). Earthen dams are susceptible for breaks (e.g. Kaddam Dam) and Polavaram case can therefore be considered as a calamity “waiting to happen”.
This alternative proposal is suggested primarily in the interest of population residing in the Godavari delta, especially in the light of the recent occurrence of Krishna huge flood of 2.7 times the ever observed maximum flood. As a matter of fact, this alternative proposal will have to be strongly favoured by the Godavari delta people instead of opposing it, since this gives all the benefits of. the earlier "Dam proposal" without any risk to their lives in future. This apprehension may be due to information gap about the alternative proposal. In the case of the alternative barrage proposal the huge incoming flood of 89 lakh cusecs will pass down the structure, as it is, without any obstruction, and hence there is no need to do any 'dam break analysis' (as there is no dam).
6) Objections raised by Orissa State Government against Polavaram Dam
Extracts from: http://www.dowrorissa.gov.in/AnnualReport/WR_AR08-09.pdf [pages 94-96]
Orissa has been frequently raising many objections on clearences given to Polavaram dam by various ministries of the Union Government and the Central Water Commission]CWC] a)Improper Permission of CWC to A.P.State to construct Embankments on Rivers in Orissa to avoid submersion of Lands due to construction of Polavaram Dam
The Orissa State Government filed a case in the Supreme Court against the Government of Andhra Pradesh under Art 131 of the Indian Constitution on 09.10.2007 with several prayers including the one on construction of Embankments to avoid submersion of lands in Orissa due to Polavaram Dam and “to declare the permission of Central Water Commission vide its letter No.6/125/2007 PAC(S) dated.11.04.2007 to construct embankments as null and void as it is not based on any technical data. CWC has not done any investigation. Further, no data has been supplied to Plaintiff State of Orissa by CWC before giving its decision.” b) Demand for implementation of 1978 Agreement under Bachawat Award ?
In the inter-state meeting held on 15.12.78, it was decided to go for the construction of Polavaram project in such a manner that maximum submergence in Orissa territory should not exceed RL 150ft at Konta/Motu due to all effects including back water effect.
The Godavari Water Dispute Tribunal (GWDT)passed its final order during April 1980.
Clause(VI) of the order states that the Polavaram project shall be cleared by the Central Water
Commission (CWC) as expeditiously as possible for MWL/FRL 150ft. The matter of design and its operation was left to CWC keeping in view all the agreements and change in operation schedule to be done in consultation with co-basin states. The design aspect was left entirely to CWC by GWDT c )Validity of Bachawat Award being Questioned ?
While the the issue of submergence in Orissa remain unresolved. The Ministry of Environment& Forest, Government of India have granted environmental clearance to the project on 25.10.2005 based on design flood of 36 lakh cusecs. In the meanwhile, the design flood of the project has been revised by CWC to the order of 50 lakh cusecs. As such, the environmental clearance given to this project can not be treated as valid and has to be revoked as the Environmental clearance was given basing on design flood of 36 lakh cusecs. d) A.P.State frequently changes Estimates on Submersion of Lands in Orissa
During the inter-state meeting held on 26.2.1997,Government of Andhra Pradesh intimated that at 36 lakh cusecs design flood the water level may go up to RL 182 feet due to back water effect. As a result 7 villages (1026 ha of land) in Orissa territory are likely to be affected.
Further Govt. of Andhra Pradesh intimated during March 2001 that 10 villages and 2119.38ha. of land were likely to be affected in Orissa territory. 648.05 ha. of land would be submerged at RL 150 ft. which includes 102.16 ha. of reserve forest in Orissa territory. These values are based on the remote sensing data. http://tshivajirao.blogspot.com/2010/05/insufficient-and-defective-clearances.html
Born in 1932 at Mudinepalli, near Gudivada, Krishna Dist. Andhra Pradesh, received Bachelors degree in Civil Engg., from Viswesaraiah Engineering College, Banglore (1956) and Masters Degree in Environmental Engineering from Rice university, Houston, Texas, (USA) (1962), Ph.D (Hony). Former Head of the Department of Civil Engineering and principal of College of Engineering, Andhra university.Formerly Hony.Professor in Andhra University,Manonmanian Sundarnar University,JNT University. Fellow of the Institution of Engineers,India
Recipient of the University Grants Commissions National Award "Swami Pranavananda Award on Ecology and Environmental Sciences" for the year 1991. Recipient of Sivananda Eminent Citizen Award for 2002 by Sanathana Dharma Charitable Trust, Andhra Pradesh state. Presently Working as Director, centre for Environmental Studies, GITAM University,
http://www.geocities.com/prof_shivajirao/resume.html
http://www.eoearth.org/contributor/Shivaji.rao
By Vadim Sablo
