Saturday, June 27, 2009

Tipaimukh Dam: Its nuts and bolts need dovetailing

A. Mannan

Ignorance is a bliss. It does appear to be so to many of us shown by portrayal of our body language as well as vocabulary inasmuch as the magnitudes of the portents of Tipaimukh Dam that are rushing towards Bangladesh like a giant amoebic demon are yet to be grasped fully.

Presentation in this article has been dovetailed through collation, analysis and summation of the nuts and bolts of Tipaimukh Dam in order to help, to some extent, keep ourselves aware and abreast of the situation. Data have been obtained from sources like, speeches, write-ups, through interpolation, through line of best-fits based on statistical average theory and some upon off-hand estimates.

Concise background:

Farakka Barrage (FB) :-It has been a burning issue since the mid-sixties. India did not pay much heed to the demand and necessity of water of the Ganges by the lower riparian Bangladesh. India unilaterally constructed the FB experimentally in 1972 with the concept and stipulation therefor to divert small portion of the water of the Ganges flow to the river Bhagirathi to increase navigability of the Calcutta Port. Bangladesh, however, realized it in 1974 that the Ganges flow due to construction of FB, only 11 miles off the border started scaling down the water flow to Bangladesh by half and at times almost at zero level. In 1976 FB was put into full operation and in due course of time India started withdrawal of water not for Bhaghirathi only but at places at upstream of the Ganges, e.g. Bihar and U P, proving how fragile have been the stipulations of India, breach of which has already led to render 80 rivers drying-up and 11 rivers dead in Bangladesh. It has virtually destroyed the deltaic basin in Bangladesh.

Teesta Barrage (T.B) :-

India constructed in 1990 a barrage along the river Teesta, called the Teesta

Barrage which has in turn made the Teesta Barrage constructed by Bangladesh absolutely ineffective.

Riparian River Linking (Link Canal) :-

(i)Upper Riparian Rivers Linking: It means linking of 14 Himalayan rivers in Northern India.

(ii) Lower Riparian Rivers Linking: This project involves 16 peninsular rivers including the Ganges and Brahmaputra.The project has virtually cast its eyes for withdrawal of Brahmaputra water for diversion to the water hungry provines of U.P, Bihar, MP, Andhra, Maharashtra, Karnataka and Chennai. India is also constructing two dams in Nepal for hydropower and perhaps augmentation of water for the Ganges to divert water through the link canal to South India. Whereas Nepal has contributed sites for the dams and is likely to have its access to power and water, the project will leave for Bangladesh a high-dried scenario.

The lower riparian rivers link project is bound to change the river course from N-S to E-W course. At the rate of 6000 cu m/sec during lean period six months i.e. Dec-May flow equivalent to the total flow of 200 bn cu m for 6 months, which if withdrawn substantially for the lower riparian rivers link canal will certainly lead the GMB Basin in Bangladesh to a catastrophe affecting all spheres of activities of economy, livelihood and ecosystem.

In 2002, the Supreme Court of India gave a judgment in favour of the link canal project upon a writ petition but the Indian political arena considering internal geopolitics, pro-people stand, huge funding, inadequacy in technical feasibility and viability has so far kept mum on the issue.

Earlier, National Commission for Water Resources of India in a report in 1999 mentioned that in the lower riparian link project involving the flow of three major rivers of Bangladesh for sharing, India's portion down the Himalayas will fetch no profitability until gestation period of right up to 2050.

It may also be worth mentioning here that according to a survey a withdrawal of 20% of Brahmaputra's water by India (India asks for 40%) will render at least 100 rivers in Bangladesh as dead-dry.

China's Eye on the Brahmaputra's flow:

China has planned to build a dam upon Yarlung-Tsangpo point on the Brahmaputra river in Tibet, when completed, will divert water to the Yellow river a quantum of 200 bn cu m per annum equivalent to that of the entire lean season 6 months flow of Brahmaputra river. It is easy to comprehend as to how much India can get out of Brahmaputra's flow, once Chinese dam is put in operation, and how much can India afford to release to Bangladesh. This apprehension India has got to foresee as much as Bangladesh would, in view of the riparian state of both in the respective cases in point.

Should India outbargain Bangladesh on the issue of Tipaimukh Dam and Fulertal Barrage, on the same analogy China is likely to do that at the upstream.

Tipaimukh Dam and Fulertal Barrage:-

(i)Reference as FB, TB and specially lower riparian rivers linking canal project of 16 peninsular rivers has been cited to highlight total impacts of the three major international rivers, the Ganges, Meghna and Brahmaputra (GMB), whose downstream last riparian country is Bangladesh. That will take a heavier toll than otherwise upon operation of Tipaimukh Dam and Fulertal Barrage on Bangladesh.

In the process of desertification Bangladesh will become unlivable for Bangladeshis and soon this basin will become a no-man's land after having been inflicted by four-front attack i.e. from N-E-W river flow attack due to either shortage creating desertification or excess inundating with floods and of course from the South i.e.

Bay of Bengal wherefrom will come the upsurge of water with all its might having concentrated salinity on account of global warming due to ozone layer thinning by the discharge of CFC contributed in bulk by the most industrialized nations, though Bangladesh contributes practically nothing or little in the ozone thinning process

(ii) Dam and Barrage:-

Dam is like a reservoir to contain water at higher level for a controlled discharge through the turbines to generate electricity e.g. Karnaphully-Kaptai Dam.

Hydroelectricity project having no provision of withdrawal of water upstream or downstream of the dam will have little variation, in the quantum for the year as a whole, in the downstream water flow based on the theory of constancy for the whole year recycle, set aside seasonal variation.

But quantum of water flow downstream of the dam depending upon season will fluctuate seasonwise as well as variation in rainfalls due to controlled release of water through the turbines and spillway gates of the dam, needed to generate electricity at certain capacity and also in view of the storage capacity for holding water by the dam and level so required.

Thus, while the annual quantum of water flowing downstream will be more or less, somewhat same but the water flow downstream of the dam will fluctuate substantially either creating floods, waterlogged and waterholds or perhaps high-dried scenario almost zero flowmetry of not cognizable dimension or proportion

(iii) Barrage is to contain water at a level with objective to withdraw for diversion elsewhere e.g. F.B. The purpose of a Barrage is mainly for withdrawal to divert, but it, all, depends upon how much, when and where for withdrawal and how much to release for the lower riparian country of the total intakeflow. For example, F.B was originally designed and contemplated to make the Calcutta Port more navigable with withdrawal of water via Bhagirathi river but due to rampant withdrawal all the way through upon the Ganges flow at the upstream of F.B. desertification process has already been in progress for 16 districts i.e. one third of Bangladesh at a colossal loss of ecosystem in its entirety.

(iv) Tipaimukh Dam:- It is, in fact, a Mega Dam. India mooted much earlier river harnessing project and accordingly handed over primary project proposal to Bangladesh in 1979 and in 1983, After having completed detailed studies India, however, did never share those data with Bangladesh.

In 2003, Tipaimukh Dam was proposed for the location at ½ k.m. downstream from the confluence of Barak river and Tuivai river lying on the S-W corner of Manipur state. Due to outcry against negative impacts of the Dam across the border as well as within Manipur and Mizoram states of India, construction of the Dam could not make any headway.

India in 2004, however, assured Bangladesh that no further steps would be taken up without any consultation with Bangladesh, but India floated a tender in 2005, opened it in 2006, finalized the design and drawing in 2008, obtained environmental clearance and inaugurated foundation stone laying in 2008.

The completion of construction is due in 2012.

Some data relevant to the upstream land of the Dam are shown below:-

One of the largest rock-filled dam in the world.

Height = 166 m, (or 180 m above sea level, 178 m maximum reservoir level and 136 m minimum draw down level)

Length = 390 m

Water containment capacity = 16 m cu m

Load of the rocks = 25 m . MT (app.)

Location of the dam = 200 km (maximum) upstream from Bangladesh border.

Originating from the mountains of Manipur the total length of Barak-Tuivai in India and Surma-Kushiyiyara-Meghna in Bangladesh right up to the mouth of Bay of Bengal = 946 km (of which India = 277 km and Bangladesh = 669 km)

Submerged land in India = 286 sq. km.

(i) Submerged 8 villages

(ii)Homeless, 40,000 people

(iii) Affected 90 villages

(iv) Affected 27,000 hectares of arable land.

Electricity generation capacity = 1500 MW but firm generation fixed at the rate of 30% = 412 MW

About 8% river water to Bangladesh comes via Borak river

Fulertal Barrage: - The issue is still indiscreet. Very little details are known. Neither its aims nor objectives have been made clear. The Barrage is 100 km (app.) downstream diagonally of Tipaimukh Dam and 100 km diagonally upstream of Amalshid in Sylhet. It is apprehended that India may regulate water flow at the Dam and then divert it to the proposed Fulertal Barrage, thus having direct bearing on the flow of Surma, Kushiyara and Meghna rivers invariably affecting total ecosystem in all spheres for the 1/3 area of Bangladesh.

Earthquake Risks:- In the N-E region's earthquake risks zone i.e. Surma Basin, major events are controlled by Dauki Fault system i.e. zone 1 comprising NE region of Bangladesh. With the presence of Dauki Fault system of Eastern Sylhet and the deep seated Sylhet Fault and proximity to the Jaflong Thrust, Naga Thrust and Disang Thrust, it is a zone of high seismic risk with a basic co-efficient of 0.08.

Geographic and topographic features at Tipaimukh and adjoining areas are noteworthy due to drainage pattern of Barak river and structural and tectonic lineaments of the region.Moreover, the main Barak river opposite to Tuivai river is also controlled by Barak-Makru Thrust Fault.

Barak river course and its tributary system are controlled by faults and fractures causing localized shifting and deflection of main river course rendering such faults as potential focal or epicenters of earthquakes.

Thus, having considered the issue of high seismic risk with basic co-efficient of 0.08, past records of earthquakes in the region over last 200 years, the volume and weight of water containment up the Dam at 16 m cu m and weight load of rocks of the Mega Dam at 25 m MT (app.), Tipaimukh Dam's axis falling on a 'fault line' likely to be the epicenter, an earthquake of 7 plus Richter scale dimension will play most devastating havoc with the load and onrush of 16 m cu m water of the reservoir followed by heavy rush of upstream water and weight load of 25 m MT rocks frictioned to pieces, up and down, rushing towards Bangladesh at great speed and thus, pose a threat and might as if that of the "Dooms' Day"

(To be continued)


No comments:

Post a Comment