EXPERTS MISLEAD ON BACKWATER IMPACTS OF ALAMATTI DAM Prof.T.Shivaji Rao, Director, Center for Environmental Studies, GITAM University, Visakhapatnam
WHY CWC IS NOT GIVING DATA ON ALAMATTI BACK WATER CURVE AND DAMBRERAK ANALYSIS?see website: http://www.asianage.com/india/cwccicdrawswordsoverinfo979 http://tshivajirao.blogspot.com/2011/02/alamattibackwatercurveat_4653.html It is shocking for people of Kolhapur, Sangli and Karad of Maharashtra and Belgaum of Karnataka to know that hundreds of their villages including major cities like Sangli and Kolhapur will be forcibly drowned frequently during rainy seasons and cyclonic periods due to heavy downpours that are bound to cause extreme floods such extreme floods have to be calculated on scientific lines and by using internationally accepted envelop cures as published by the top most experts like Lempererie of France and L.Berga of Spain who worked as Chairman, Technical Committees on Floods and Dams of the International Commission on large Dams (ICOLD). Unfortunately the Engineering experts of the CWC and the State Governments of Maharashtra, Karnataka and Andhra Pradesh chose to ignore the stateofart technology on estimating the extreme floods expected in the catchment areas of Krishna river and its tributaries and they did not even consider the Probable Maximum Precipitation estimates made by International Hydrology expert like PR Rakhecha and others. Consequently these Indian experts are deliberately underestimating the extreme floods expected in Krishna river basin and Godavari river basin inspite of the fact that the October 2009 floods in Krishna river proved that the spillway design floods estimated upto the previous decade do not hold good anymore after 2010 when the stateofart technology must be followed to estimate the Probable Maximum Floods for calculation of backwater cures and to avoid dam collapses and to plan for safety of lakhs of people, their properties and agricultural wealth. In the present case of Alamatti dam a comparative statement of the backwater calculations made by the CWC and the independent experts is presented in the following pages to create awareness among the people and particularly the farmers, the nonGovernmental organizations, the intellectuals and the patriots like Anna Hazare who have to fight against the social evils being perpetrated by some of the unethical and immoral scientific and engineering experts who occupy possession of power and use the garb of development to destroy the life and culture of the farmers and farm workers who form the backbone of the social democratic welfare state. Unless the people exert pressure over the elected representatives in panchayats, state legislatures and the parliament. The present and future generations of Indian will stand to lose their right to life and the right to livelihood and right to natural resources as envisaged by the constitution of India. Backwater levels calculated from MWL/Maximum Flood Level as per Narmada Tribunal Award SubClause II  Lands Which are to be Compulsorily Acquired. II(1) : Madhya Pradesh and Maharashtra shall acquire for Sardar Sarovar Project under the provisions of the Land Acquisition Act, 1894, all lands of private ownership situated below the FRL + 138.68 m (455') of Sardar Sarovar and all interests therein not belonging to the respective States. If on the basis aforesaid, 75 per cent or more land of a contiguous holding of any person is required to be compulsorily acquired, such person shall have the option to compel compulsory acquisition of the entire contiguous holding. II(2) : Madhya Pradesh and Maharashtra shall also acquire for Sardar Sarovar Project under the provisions of the Land Acquisition Act, 1894, all buildings with their appurtenant land situated between FRL + 138.68 m (455') and MWL + 141.21 m (460') as also those affected by the backwater effect resulting from MWL + 141.21 m (460'). II(3) : The backwater level at the highest flood level in Sardar Sarovar shall be worked out by the Central Water Commission in consultation with Madhya Pradesh and Gujarat. http://nca.gov.in/forms_pdf/nwdt_finalorder.pdf Govt. of India, Central Water Commission, F.E. & S.A Directorate Backwater study for Alamatti and Hippargi Reservoirs in Karnataka 1. INTRODUCTION: Director, Project Appraisal (S), CWC vide U.O. No.21/10/99PA(S)/585 dated 29^{th} May 2003 requested for an independent study by FE&SA Dte.. CWC regarding the backwater effects and submergence in Maharashtra territory due to construction of Alamatti and Hippargi Reservoirs in Karnataka, in pursuance of the decision taken in the meeting held on 23299 under the chairmanship of Chairman, CWC. The original study regarding backwater effects and submergence in Maharashtra territory due to construction of Alamatti and Hippargi Reservoirs in Karnataka was carried out by Indian Institute of Science, Bangalore which was submitted by the Karnataka Government. The then Direcotr (FE &SA) vide lr.No.CWC/DBAG/FE&SA/2001/602 dt.11^{th} June 2003 observed that the methodology adopted for the back water study and the value of the rugosity coefficient taken for the study were found to be in order. However, in cae an independent confirmation of the result is required then necessary data/information may be supplied to FE&SA directorate. Subsequently, necessary data comprising of cross sections of Krishna river upstream of Almatti dam and Hippargi Barrage and rating curve of Almatti spillway submitted by Government of Maharashtra and Karnataka were forwarded to this Directorate vide U.O.No.21/10/2004PA(S)/1246 dated 22^{nd} December, 2004. Accordingly, a study was carried out in FE&SA Directorate using onedimensional mathematical model MIKE 11. 2. SCENARIO STUDIED: Following scenario were considered for study of backwater effects and submergence in Maharashtra territority due to construction of Almatti and Hippargi Reservervoirs in Karnataka; 1. PMF discharge of 31000 cumec at Almatti and 24609 cumecs (proportionate discharge proportional to square root of catchment area as per suggestion of the February, 1999 meeting at CWC as mentioned in back water study report of IISC, Bangalore) at Hippargi taking Almatti FRL at 524.25m, considering both Almatti and Hippargi reservoirs. 2. PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi taking Almatti FRL at 524.25m, considering Almatti reservoir only, as Hippargi is yet to be constructed. 3. PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi taking Almatti FRL at 519.60m, considering both Almatti and Hioppargi reservoirs. 4. PMF discharge of 31000 cumec at Almatti and PMF discharge 25485 cumec at Hippargi taking Almatti FRL at 519.60m, considering Almatti reservoir only, as Hippargi is yet to be constructed. 5. This yars discharge of 10100 cumec at Almatti and 9000 cumec u/s of Hippargi taking Almatti FRL at 519.60m, considering Almatti reservoir only. 3. STUDY RESULTS: The results of hydrohynaci modeling of Krishna river upstream of Almatti dam under various scenario, enumerated above, are tabulated in Tables 1 to 5 respectively. The corresponding plots of water surface profiles are given in plate 1 to 5 . From the above tables and plates it can be seen. i) The backwater profile of Almatti dam for FRL at 524.25m PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi, considering both Almatti and Hippargi reservoirs merges with water profile in the natural condition of Krishna river, just downstream of the Hippargi barrage (Table 1 and Plate 1). Hence the backwater effect of Almatti reservoir is upto the downstream of Hippargi barrage is upto about 221 km upstream of Almatti dam. ii) The backwater profile of Almatti dam for FRL at 524.25m, PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi, considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 145 km upstream of Almatti dam (Table 2 and Plate 2) iii) The backwater profile of Almatti dam for FRL at 519.60 PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi considering both Almatti and Hippargi reservoir, merges with water profile in natural condition of Krishna river just downstream of the Hippargi barrage (Table 3 and Plate3). Hence the backwater effect of Almatti reservoir is upto the downstream of Hipprgi barrge only. The backwater effect of Hippargi barrage is upto about 221km upstream of Almatti dam. iv) The backwater profile of Almatti dam for FRL at 519.60 , PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi, considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 126km upstream of Almati dam (Table 4 and Plate 4) v) The backwater profile of Almatti dam for FRL at 519.60m for this years flood of 10100 cumec considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 175km upstream of Almatti dam (Table 5 and Plate 5). 4. COMPARISION WITH IISC STUDY: The study carried out for case 1 and above has been compared with IISC, Bangalore study. The trend of profile has been found to be matching. However, there is a difference of 12m in water level at different cross sections of Krishna river u/s of Almatti dam. This is due to difference in method of backwater calculation. The IISC Bangalore has used the standard step method, which is an approximate method to calculate the profile. In the above method, first the trial value of water level at the upstream location is assumed based on the known water level at the downstream location. The velocity is then calculated dividing the discharge with the cross section area corresponding to assumed water surface. This gives a lower velocity in comparison to the velocity calculated by MIKE 11 model using finite difference solution of St.Venants’s equations of conservation of mass and momentum. Hydrodynamic modeling used in MIKE11 models the complete river stretch together to provide physically balanced water surface profile, which is more accurate than the approximate standard step method. Table1: Back water calculations for Almatti FRL at 524.25m with Almatti and Hippargi (Discharge considered 31000 cumec at Almatti, 24609 cumec at Hippargi)
*A  C/S inserted for specifying Hipp.Barr *B  11 /11A11A (Hippargi Barrage) Table2: Back water calculations for Almatti FRL at 524.25m with Almatti (Discharge considered 31000 cumec at Almatti, 24609 cumec at Hippargi)
Table3: Back water calculations for Almatti FRL at 519.6 with Almatti (Discharge considered 31000 cumec at Almatti, 25485 cumec at Hippargi)
*A  C/S inserted for specifying Hipp.Barr *B  11 /11A11A (Hippargi Barrage) Table4: Back water calculations for Almatti FRL at 519.6 with Almatti (Discharge considered 31000 cumec at Almatti, 25485 cumec at Hippargi)
*A  C/S inserted for specifying Hipp.Barr *B  11 /11A11A (Hippargi Barrage) Table5: Back water calculations for Almatti FRL at 519.6 with Almatti (Discharge considered 10100 cumec at Almatti, 9000 cumec at Hippargi upstream)
According to the international Irrigation expert Dr.Lempererie, Chairman of ICOLD committee for France, the extreme flood is calculated by the formula S>3000Km^{2}, Q=10,000(S/300)^{0.4} as published in his paper under the website: http://bhujangam.blogspot.com/2010/12/damsandfloods.html http://www.hydrocoop.org/Shall_we_forget_the_traditional_design_flood.doc The extreme Probable Maximum Flood for Alamatti dam with a catchment area of 35,200 sq.km works out to 67,300 cumecs. However we opted to use 50,000 cumecs as PMF value for calculating the backwater curve for Alamatti Dam by using Mannings coefficient of 0.05 According to table6 in the website the PMF in cumecs could be 2 to 3 times the catchment area measured in sq.km as in the case of Gandhi Sagar catchment area on Chambal river in Madhya Pradesh. Hence the peak flood assumed by the CWC for Alamati dam is an underestimate and the backwater calculations are also under estimated and hence the engineers of the Karnataka and Maharashtra state are completely mislead on the issue of submersion of Sangli and Kolhapur areas due to backwater impacts of Alamatti dam. http://onlinelibrary.wiley.com/doi/10.1017/S1350482700001389/pdf Roughness Coefficients (Manning’s “n”) for Overland Flow http://www.shippensburgtownship.com/201001/media/development/Table%20B4.pdf
* Based on pipe diameter and manufacturer’s design specifications
Comments :The information in this table clearly shows that Sangli city will experience floods due to backwater curve upto an elevation 552.35m while the backwater levels presented by the CWC experts show an elevation of flood only upto 544.0m . This difference is due to differences in the input data used by the different authors. The calculations made by the independent authors show that Sangli and Kolhapur will be submerged under the depth of more than 8m of floods due to backwater curve. Consequently hundreds of villages all along the course of the river between Kolhapur, Sangli and Karad districts and Alamatti dam will be submerged resulting in great losses.
