Comments on Dr. Nargis Banu's Paper
and
Advantages and Disadvantages of Tipaimukh Dam
- Part 1

Bijon B. Sarma *

PREAMBLE :

When we write in websites normally we do not write with utmost seriousness, and we know the reason. Even though lapses/problems in languages are acceptable, in the articles on serious science-based subjects, ideas and thoughts by all means should be specific and expression of intelligence. I did not have any intention to review Environmental Geologist (Kansas, USA) Mr. Meer Husain's article 'CONSTRUCTION OF TIPAIMUKH DAM - A THREAT TO THE NATIONAL INTEREST OF BANGLADESH'.

I did it because he requested me to go through that. Accordingly I did and published my submission. However, the time I went through his paper I was really shocked to see that a person with such expertise uses 'a high-school student's essay' collected from source like 'wikianswer.com' in his paper.

Then I felt tempted to review Dr Nargis Banu's article 'PROTECT PEOPLE AND NATURE FROM TIPAIMUKH DAM', posted by the Bangladesh Expatriate Council. Dr. Hasina Banu is an environmental scientist working with Sydney Water Corporation, Australia. It was mentioned that the paper was presented at a seminar at the Australian National University on July 3, 2009.

By disclosing this information the writer has given us a scope to know what type of papers are presented in such seminars. This author has experiences of such presentations at home and abroad, including Australia.

COMMENTS OF PAPER BY DR. NARGIS BANU

01. DR. NARGIS BANU SAYS : At the beginning (probably Introduction, where Abstract is missing) Dr. Nargis Banu narrated the background story of Tipaimukh project. Here she mentioned two notable issues:
(Quoted). (a) With the construction of Tipaimukh Dam, India would be diverting the Barak's water flow from its north to its south and east. it will have adverse impacts on nature and livelihood in the north-eastern districts in Bangladesh.
(b) Now India has started another intervention on the international river barak at Tipaimukh and will construct a dam at fulertal (100 kilometres downstream from tipaimukh) by 2012.

MY SUBMISSION : The truth is, India initiated construction of a barrage at Fulertal (adjacent to Bangladesh border) long ago and the same has now been abandoned. Now India has proposed for the construction of a dam for the production of hydroelectricity at Tipaimukh, a place located at a distance of over 150 kilometres. Dam and Barrage are two different things. Where as withdrawal of water is the essential objective of barrage, a dam may or may not have such provision.

India has already assured that there will be no withdrawal of water. In such a situation a comment like 'with the construction of Tipaimukh Dam, India would be diverting the barak's water flow from its north to its south and east' is misleading. And if this statement is wrong, the comment based on it and expressed in the following line i.e. (quoted) 'It will have adverse impacts on nature and livelihood in the north-eastern districts in bangladesh' is also wrong.

Those who are aware of the topography, soil condition and climate of Monipur region might know that this region does not really need such diversion of water for irrigation. Let me briefly explain the reason. There may be two prominent reasons of depositing water in the mountains or hills.

(a) In the high rocky mountains water is deposited in cavities and on the picks as ice during the winter. In the summer season those melt and flow down.
(b) The earth-made hills and mounds get wet during rains and release that water as spring or fall, resulting in small canals (local name 'Chhara'). Depending of the size of the mounds, this water may flow throughout the year. While the main source of water in Barak river is the first type, that locally used in Monipur region belongs to the second type.

02. DR. NARGIS BANU SAYS : The author has given some information to prove that there is probability of severe earthquakes in this region.

MY SUBMISSION : It is an established fact that
(a) Monipur-Assam-Sylhet zone is highly earthquake prone,
(b) Large deposit of water at heights intensifies vibration during earth-quake and
(c) Breaking of dam during such hazard would cause havoc. It is obvious that when such a site is found economically feasible and ecologically superior (in comparison with other means of generation of electricity) for a hydro-electric project, the engineers would go for the construction of a safe dam, even if it is costly.

In case of breakage of this dam the most affected country will be India due to the following two major reasons :
(a) Failure of an extremely expensive project and
(b) Catastrophic flooding in the 150 kilometre-stretched land within India.

03. DR. NARGIS BANU SAYS : The author mentioned (quoted) 'the expert appraisal committee of india revealed that the design of the dam contains many errors, and omissions, and falls short of compliance of standards set by the scientific and academic community in india and the world'.

MY SUBMISSION : The fact is, the design of Tipaimukh dam has not been finalized. No one should wonder about such comments by various corners (like, expert appraisal committee) during the preliminary stage of its preparation.

04. DR. NARGIS BANU SAYS : (quoted) 'India conducted detailed studies, completed the final design and environment impact assessment without consultation with bangladesh as a downstream stakeholder'.

MY SUBMISSION : The statement like 'completed the final design' is definitely untrue.

05. DR. NARGIS BANU SAYS : (quoted) 'Indian Government has not clearly stated the amounts of water that will be stopped or diverted with the construction of the tipaimukh dam'.

MY SUBMISSION : The author's statement is not only untrue, but also misleading because the Indian government has stated that it would not divert any water.

06. DR. NARGIS BANU SAYS : (quoted) 'the erosion just downstream of the tipaimukh dam would be excessively high and this erosion would continue as long as hundred kilometres downstream or more in the surma-kushiara system'.

MY SUBMISSION : This statement is wrong. As a matter of fact, after a dam is constructed, the erosion in the down stream is reduced. Let me explain the reason in brief. Soil erosion among other factors depends upon on the velocity of water. The velocity depends among others on two principal factors :
(a) Quantity of water and
(b) Inclination (also known as gradient) of flow-path. After the construction of the dam, the flow of water will be less in the lower region during monsoon months (because the dam would reserve additional water) and the same would increase a little during lean period.

In fact the flow would never attain the highest level that it had before the construction of the dam. As we mentioned, the flow also depends upon inclination of flow-path. A dam constructed on a river considerably reduces this inclination. The dam in fact utilizes the potential energy (in this case energy stored in water due to gravitational force) of the water in the reservoir. After the water starts its fresh journey from a considerably lower level, it loses degree of inclination. Naturally it loses velocity and eroding capability.

07. DR. NARGIS BANU SAYS : (quoted) 'the ... deposition .... will raise the overall bed level of the rivers'. About the affects of silting she commented (01) '... an extreme case it would block the mouth of certain tributaries, and (02) 'will induce the average monsoon flood to become moderate to severe flood in the surma-kushiara floodplain'.

MY SUBMISSION : All these are against the natural rule of science. The fact is, the water carried by the river after the dam would create less siltation because
(i) It would erode less due to the reduced velocity of water and (ii) The dam would arrest the entire sedimentation particles coming from above.

08. DR. NARGIS BANU SAYS : (quoted) 'about 71 per cent of the upper surma-kushiara basin area would no longer be flooded. ... the kushiara-bardal haor .... would become completely dry. the kawardighi haor .... lose around 2,979 ha (26 per cent).'.

MY SUBMISSION : If it really happens like it, then the people of this area would think them fortunate to become free from flood hazard and to get new land.

09. DR. NARGIS BANU SAYS : (quoted) ' ... kushiara would cut its connection with its right bank floodplain ...... and this part will become 'reservoir river' rather than a most valuable 'floodplain river' (prophesy).

MY SUBMISSION : If this prophesy is based on the author's hypothesis of 'increased siltation', then I have explained why it would not take place. However, those who have knowledge of soil structure, inconsistency of river flow etc. of Bangladesh can guess that the new situation might help in straightening the snaking and winding courses of some rivers, thus generating a number of ox-bow lakes. This should be taken as a positive contribution because the more land the rivers would release the better it would be for the country.

10. DR. NARGIS BANU SAYS : (quoted) 'millions of people are dependent on ... barak for agricultural activities. the dam would cause the surma and kushiara to run dry from november to may'.

MY SUBMISSION : This is a wrong statement. The fact is, release of submerged land due to lower level of water in the rainy season and straightening of rivers may release more land, such that more people may be engaged in agriculture. Before making such a statement the author should have studied the basic principle on which a dam for hydraulic project works. Let me explain briefly.

In hydro-electric project the available height of water in the reservoir above the exit-hole is of extreme importance. For the running of the generators water has to be constantly released from the reservoir. The quantity of power generated is proportional to the height of water in the reservoir.

With normal discharge let the height of water during the rainy season is (all arbitrary numbers) say, 100 Feet and that in the lean period (i.e. winter) say, 50 Feet. For optimum production and economic feasibility the designers would have to arrange generators to run by a height in between these two figures (not necessarily the average). Let us say this number is 60 Feet.

In this case the generators would not be able to run at full swing unless during winter nonths unless there is arrangement for storing additional water in the reservoir. This indicates, what the Tipai-authority would do for the smooth-running of their plant throughout the year is, storing extra water during the peak period and releasing the same during lean period. This is exactly what the experts employed by Khaleda Zia's BNP government opined, and to which any scientist or expert would have to agree.

N.B. STRAIGHTENING OF RIVER : It should be noted here that human interference is essential for initial straightening of river. In the country with soft soil, intermittent flow acts against straightening. Once the rivers are cut straight and constant flow is ensured, river may continue to flow in straight line. Such a program can release huge land on both sides.

to be continued.....