Save Adivasis, Ecology & Ramalayam from Damn Polavaram- Prof Shivaji సెప్టెంబర్ 30, 2007Posted by bharath in Appeals, Bhadrachalam, Godavari, Koya.
Killer Polavaram Dam must be changed into a Barrage to save people
To save the Bhadrachalam’s most sacred Rama Temple and several tribal villages from submersion by the Polavaram dam which can be made people friendly by converting it into a barrage the arguments to be advanced by Chattisgarh and Orissa in the Supreme Court are likely to be on the following lines for convincing A.P state to agree for replacement of the Big Dam by a smaller Barrage as previously suggested by Dr. A N Khosla, former Governor of Orissa.
1] The states of Orissa and Chattisgarh consider Dr. K L Rao, the former Union Minister for Water Resources as an eminent authority on irrigation projects like big dams. In the case of Polavaram project he made a frank statement (Indian Express news paper from Vijayawada, dated 30-4-1983) that the Polavaram dam is highly under-designed and hence a prescription for disaster. Dr. K L Rao ruled out the possibility of diverting surplus Godavari waters to the Krishna owing to defective designing of the Polavaram project only 1800 ft spillway was provided in the Polavaram project to clear 40 lakh cusecs of flood waters in the Godavari as against 13,000 ft long Dowlaiswaram anicut designed by Sir Arthur Cotton. Even Prakasam barrage was [over Krishna River at Vijayawada] designed to 6,280 ft long though the flood water would not be more than 12 lakh cusecs, Dr. Rao said.
It was simple arithmetic to understand that the Polavaram design would not work, he said.
2] In the light of these serous technical comments from a very experienced expert Dr. K L Rao, the Orissa and Chattisgarh state Governments demand for a revision of the Polavaram project to ensure safety of people in all the states. The intellectuals and the common people of Orissa and Chattisgarh have also carefully studied various websites on Polavaram project including the following ones.
In the light of the above expert views presented in detail on Polavaram project we demand for reconsideration for the replacement of the proposed dam with a barrage to divert 80 TMC of Godavari water into Krishna River as promised by the A.P. state.3] At the end of Paragraph 110 of the Bachawat Tribunal report it has been emphasized that a distinction must be drawn between submergence as a consequence of construction of the dam and submergence without the dam. The Bachawat tribunal suggested for avoiding or minimizing as far as possible the excess submergence caused by backwater due to construction of the Polavaram dam. For this purpose the tribunal insisted that the correct backwater effect /level due to Polavaram dam shall be determined by the Central Water Commission (CWC).
4] Under paragraph 112 the tribunal wanted reduction in full supply levels of the right and left bank canals to slightly lower than +138 ft and +137 ft and the effects of such reduction can be made good by introduction of lift irrigation systems on both sides. But Orissa and Madhya Pradesh insisted on 2-9-1979 that in order to limit the submergence to +150 ft, the FRL/MWL must be reduced. But the A.P State Government prepared Environmental Impact Assessment report[EIA], Dam break analysis and Rehabilitation and Resettlement schemes on the assumption of a 500 year return flood of 36 lakhs cusecs. But the CWC norms of 1973 insist on estimating design flood as Probable Maximum Flood [PMF] or at least 1000 year return flood.
5] In August 2006 the AP state Government increased the design spillway flood from 36 lakhs cusecs to 49.5 lakhs cusecs and hence all the environmental clearances and rehabilitation and resettlement schemes based upon inappropriate data on design spillway flood become invalid and hence fresh clearances must be obtained from the various ministries of Government of India. In order to prepare the backwater curve for Polavaram dam the CWC first of all must estimate the PMF based on various factors including the Probable Maximum Precipitation (PMP). CWC must revise the existing records by considering the latest reports on the impacts of Global warming due to increasing levels of deforestation and environmental pollution which are said to cause about 20% excess flood flows in Godavari and Narmada basins. CWC must estimate PMF for Polavaram dam based on similar estimates made for Sardar Sarovar Project CWC has estimated for design purposes a return flood period of 1 in 1000 years and the design flood was taken as 87,000 cumecs for the river catchment of 88,000 sq.kms and this is in tune with the latest design criteria formulated by the reputed experts of the International Commission on Large Dams, namely, L.Berga and F.Lemperiere who estimated the extreme flood at the rate of one cubic meter per second for sq.km of the catchment area.
6] On this basis the peak flood in Godavari at Polavaram for the catchment area of 3,06,643 sq.km comes to about 3,00,000 cumecs/ sec which is equivalent to about 100 lakh cusecs and a similar figure of 2,91,693 cumecs was used for sensitive analysis under case – III (B) in the dam break analysis report submitted to the A.P State Government in June 1999 by the experts of the Roorkee based National Institute of Hydrology which is a technical wing of the water resources Ministry of the Government of India. Many countries in the world use Probable Maximum Flood (PMF) as the design flood for embankment dams due to the weakness of structure and a high rate of failure. The overall failure rate is estimated at 1% and the annual failure risk for any dam is about 0.00001. In China the design flood is used for ordinary dams and structures that are exposed to normal flood conditions. But for structures, whose failure will cause heavy loss of life and property, the PMF should be considered as the extraordinary condition (Check condition) for embankment dams and a 10,000 year flood is adopted for concrete dams. For instance the design check flood criteria for embankment dams of Class-I is taken as PMF or 10,000 return period flood. The safety criteria for peak design flood for dams in United Kingdom, USA and International Design Floods in South East Asia under
7] Thus in deciding about the magnitude of Design flood for spillway it is not only the hydrological aspect but also the magnitude of the project in terms of the height of the dam and the water storage that should be considered. Moreover the downstream hazard potential and the type of the dam (concrete or embankment dams) also should be considered for choosing the design flood. This criteria was not followed by the Bachawat tribunal. In the case of the Polavaram project the experts of the National Institute of Hydrology considered the previous historical flood of 35 lakh cusecs (one lakh cubic meters/sec) but also the flood flow arising from transformation of the stagnant reservoir storage of about 194 TMC behind the dam and the consequential flow and hence the inflow flood was taken as 1,70,000 cumecs. If the Polavaram project gets rid of the dam and replaces it with a barrage there will be only natural peak floods of the order of historical flood of 1986 of one lakh cumecs which can be handled by the existing structures.
8] Hence a barrage must be preferred at Polavaram instead of the dam because the dam contributes for a huge quantity of extra flood flow that causes a disaster, killing millions of people in Godavari delta. Such a catastrophic failure of the dam leads to economic ruination of the Andhra Pradesh state in particular and the whole country in general. Since Orissa and Chattisgarh state Governments are against economic ruination of India due to a Dam burst at Polavaram, a revision of the project must be made immediately.
9) The people of Orissa and Chattisgarh are worried that there will be extensive additional submersion of forest lands and tribal villages and displacement of thousands of tribals from Chattisgarh and Orissa due to construction of a big dam instead of barrage across Godavari at Polavaram. They are shocked that while the original interstate agreement between Andhra Pradesh, Chattisgarh and Orissa has been based on peak flood discharge of 36 lakhs cusecs on the basis of a 500-year return flood while the Central Water Commission [CWC] directed AP state to follow the Design standards for Dams and redesign the project for Probable Maximum Flood (PMF) which is about 1.5 times the previous historical flood, The PMF is estimated at 49.5 lakh cusecs.
Due to this change in peak flood for spillway design, the original character of the whole project has been drastically changed and hence the Bachawat Tribunal Award based upon the interstate agreement dt.2-4-1980 and the endorsement dt.3-4-1980 of the Government of India make the Award invalid under the present conditions including Environmental Protection Act, 1986 that came into operation in 1986. Hence the project has to be redesigned.
10] A.P State Government originally promised that Polavaram dam water storage will be so regulated that the submersion of lands and villages in Orissa and Chattisgarh will not exceed +150ft above the
mean sea level. But with the increase of peak flood from 36 lakhs cusecs to the PMF of 49.5 lakhs cusecs, the backwater curve due to the dam is estimated to reach about +190ft elevation at Konta and Motu regions and this will result in extensive submersion of good forests and submersion of about 100 additional villages.
Such a large scale submersion will cause migration of lakhs tribals into the upper hilly areas for resettlement where extensive deforestation will cause havoc to the local eco-systems, soil erosion and siltation of tanks and reservoirs in the lower regions.
11] Since Godavari will have floods only for about 3 months from July to September it is not possible to generate 960MW of hydro-electricity during the remain 9 months of the year when there will be not much flow in the river . Hence the contention of the AP State Engineers that they require a huge dam instead of a barrage for the sake of power generation is not correct. This is merely a pretext to have a big dam at Polavaram instead of a barrage as suggested by Dr. A N Khosla’ s Technical committee of 1953 and Dr. D N Gulhati’ s Technical Committee of 1963.Thus the project needs to be revised. Most of the people in Orissa and Chattisgarh regularly undertake pilgrimage to the most famous and Sacred temple of Rama at Bhadrachalam and the lakhs of Hindu devotees of this temple are demanding that they do not want Orissa and Chattisgarh state Governments to agree for the construction of a big dam at Polavaram which has to deal with peak flood of 50 lakhs cusecs and such a flood is bound to have a back water curve up to Bhadrachalam and the back-up flood waters will drown this holy temple and that should be avoided to protect the culture of the people of the region.
12] During August 2006 the floods in Godavari at the level of 28.5 lakh cusecs is reported to have inundated lands which affected 2.5 lakhs of people in 369 villages while the state Government estimated that for a peak flood of 36 lakhs cusecs about 1,80,000 people will be displaced from 276 villages including 4 from Chattisgarh and 8 from Orissa. Hence the A.P State Government has underestimated the figures for inundation due to floods. It is estimated that about 100 villages will be affected in the upper states including 30 villages in Chattisgarh. Hence the Polavaram dam must be constructed without submerging any forests and tribal villages in Orissa and Chattisgarh.
13] With regard to the action to be taken by the people of Andhra Pradesh for obtaining the Godavari waters by diverting the same from Polavaram they must consider the objections raised by the Chattisgarh and Orissa state Governments and also the views of the most reputed experts like Dr. K L Rao, Dr. A N Khosla and Dr.N D Gulhati under the existing circumstances the people of Andhra Pradesh must exert pressure over their elected representatives to demand for a barrage in place of a very hazardous dam to augment water supply in Krishna river and thereby provide water for drought prone districts of Rayalaseema and Telangana.
It is only the Engineers and bureaucrats who fighting for a big dam for their own selfish interests even at the cost of public interest. If necessary public debates must be conducted in different places in the state so that the interests of the interests of the state and the nation are protected. The people of Orissa must debate on this crucial problem and advise the Government on the action to be taken to avoid a man-made disaster so that the economic disaster of the nation can be avoided. Prof T Shivaji Rao
Director, Centre for Environmental Studies,
Gitam University, Visakhapatnam- 530 045