Every year some parts of India are flooded while some parts experience severe drought. This happens every year. So this year the Supreme Court of India directed the Central Govt. to look into linking the major rivers of India.
“India’s political water dance”:http://www.bangkokpost.com/News/26Apr2003_news28.html
bq. While hearing a case on the Kavery waters dispute, the Supreme Court last year directed the central government to revive an old proposal that envisaged linking of rivers to transfer surplus water from the north to rivers in the south. The objective of the plan is to break the vicious cycle of drought-flood-drought.
The plan is ambitious
bq. The 15-year plan, estimated to cost US$112 billion (at 1990 price levels), envisages creating 30 inter-basin links to transfer water from surplus to deficit basins, and to prevent surplus water from flowing into the sea. Besides flood control in the Ganges and Brahmaputra basins and drought-proofing in perennial drought-prone regions, the government cites additional irrigation coverage of 35 million hectares and generation of 30,000 megawatt of hydropower as major benefits of the proposed inter-linking.
This article is well written, but the last line gives the political angle away.
bq. The plan is already seen as a political gameplan of the Vajpayee government to win popular support in next year’s general elections.
Even though the author mentioned few paragraphs above that it was the Supreme Court which asked that this be looked into, he finally converted it and gave a political angle.
River Linking
Published
if there is no contorversy, and political issues we can think and take feasiblity studies on inter river basin transfers. no one is agreeing to link the rivers. people r saying that now this river is surplus, may be in near future river flows r not sufficient to their needs. vigourous studies has to to be done to think about river linking.
sirisha
research scholar
iit roorkee
Problems and Prospects of Brahmaputra-Ganga River Linking
Bibhash Sarma
Lecturer, Civil Engineering Dept.
Assam Engineering College, Guwahati-781013
E mail:bsarma2002@yahoo.co.in
The constantly increasing population, increasing water demands for various basic and developmental purposes have forced engineers and planners to contemplate and propose more comprehensive, complex and ambitious plans for water resources systems. The development, conservation and efficient use of water forms one of the main elements in the development planning. The water resources are limited considering the future demands. In India, the rainfall is mostly confined to the monsoon season and is unevenly distributed both in space and time even during the monsoon season. As a result, frequent droughts are experienced and nearly one third of the country is drought prone. In the monsoon, flood waters, which otherwise run waste into the sea can be conserved in various storage reservoirs and can be utilized for beneficial purposes during non-monsoon periods. If the water availability and requirements of various river basins are assessed realistically, then planning can be done to transfer water from water surplus basins to basins that are deficit in water. Inter-basin water transfer through inter-linking of rivers is viewed as an approach to correct the natural imbalance due to inequitable distribution of water resources.
Recently the Supreme Court of India has directed the Government of India to inter-link all the major rivers in India for inter-basin transfer of water. This requires construction of large river link projects, which need investigations, careful planning and huge expenditure. A wrong implementation of these projects may be more harmful than doing nothing at all.
In India, as per the National Water Development Agency (NWDA) guidelines, water can be transferred from a river basin to another, only when the exporting basin is surplus in its surface water resources at 75% annual dependability. For determining whether a river basin is surplus or deficit in its surface water resources in comparison to basin?s annual water demands, an assessment of the annual water balance of each river basin is carried out. Here, the water balance meant a comparison between the river basin?s annual surface water availability and annual water demands, and differs from the conventional meaning of water balance. In water balance study (WBS), annual water demands are calculated for different purposes like municipal, irrigation, industrial, hydropower, salinity etc for the projection year of 2050 (with the expectation that population will hopefully be stabilized by that time) and then compared with 75% dependable annual available water. The 75% dependable annual water means the volume of water that will always be available in any 75 years out of 100 years. If surplus water exists after meeting all the demands, that can be exported.
The concern of the people of northeast is the proposed Manas-Sankosh-Tista-Ganga link, known as Brahmaputra-Ganga link. The link is proposed to take out 823 million cubic metre (MCM) of water from Brahmaputra basin to Ganga basin. The link involves canals and around 100 m of lift (pumping).
Some comments on NWDA methodology
The NWDA was doing WBS on annual basis, and recently started doing it on a seasonal (monsoon and non monsoon) basis. Research experiences indicate that yearly or seasonal analysis cannot show the important temporal variation of water availability, and only monthly or fortnightly analysis can represent the time wise water availability in comparison to water demands. Also non-monsoon period in the northeast and rests of India are different. April, May and part of June are considered as non-monsoon period in rest of India, whereas Assam receives lot of rain in this period. So only this period may be sufficient to establish the non-monsoon period ?water surplus?, whereas practically little water may be available during December to May. So an in depth assessment of water resources on monthly basis is a must for Brahmaputra basin.
NWDA studies do not account for inland navigation and wetland conservation. Brahmaputra is declared as national water highway and requires at least 2.5m depth of water at any period of year for navigation.
Water transfer study made by NWDA does not include ecological and morphological changes in the concerned basins.
NWDA does not apply the modern optimization techniques and follows the traditional methods for reservoir planning and operation. These traditional methods are less accurate and cannot consider some critical parameters of the system behavior.
Prospects of Brahmaputra-Ganga link
o The main beneficiary of the concerned link is the water receiving Ganga basin. With the added import water, municipal and industrial water supply can be increased, more area can be irrigated and navigation facilities will improve. This implies growth of industry, increased food production and less cost in navigation.
o For the donor Brahmaputra basin, the main benefit is the sanction of new reservoirs and the associated benefits from these reservoirs. The link canal may also serve as feeder irrigation canal to serve branch irrigation canals. The flood peak in the down stream of reservoirs can be moderated by reservoir operation, if provision is kept in reservoirs for flood absorption.
Problems of Brahmaputra-Ganga link
o The Brahmaputra basin is narrow and it has limited suitable sites for storage reservoirs. Though it is said very often that Brahmaputra has huge surplus water, the approximate percentage of technologically exploitable water is only 10% out of the gross amount (Dr KL Rao, former Union irrigation minister). Water that cannot be exploited will simply pass through the basin. If whatever limited sites are available for storage reservoirs, parts of them are used for water export to other basins; the basin will leave with little volume of technologically utilizable water. So the scope of future development of the basin will reduce.
o The link canal between the reservoirs will disturb the land communication system. Bridges at short regular intervals are to be constructed.
o Brahmaputra basin will like to export maximum water during flood season. But the receiving basin also experience floods during the same period and may not be willing to accept additional import water.
Some pre-requisite for the Brahmaputra-Ganga link system
Before taking a final decision on Brahmaputra-Ganga link system, the following aspects need to be studied.
o Assessment of water resources of Brahmaputra basin on monthly basis.
o Consideration of environmental and navigational needs of Brahmaputra basin.
o Required dam heights for reservoirs to sufficiently mitigate floods.
o Identification of suitable reservoir sites all over the basin to increase volume of technologically utilizable water, on the basis of topography, geology, river morphology, seismology and human evacuation.
o Hydropower potential and flood detention capacity of the basin.
o Use of system analysis techniques to maximize utilization of available water, the import requirements of the receiving basin, and the exporting capacity of the donor basin after fulfilling all its local demands.
o Effect of water transfer on existing wetlands, water chemistry, aquatic lives and river morphology.
The driving force for Brahmaputra-Ganga link should be the diversion of floodwater and not valuable storage water during non-monsoon period. Possibility of earning revenue from water transfer should also be carefully studied. Sowansiri, Dibong, Lohit and Dihang tributaries contributes more than 60% of discharge of river Brahmaputra. Topography does not allow large storage reservoirs at Dibang and Lohit. Proposed reservoir sites at Sowansiri and Dihang have the potential to reduce the flood peak considerably, if dam sites and heights are planned not only for hydropower generation, but also for flood mitigation. Implementation of the Sowansiri and Dihang projects with flood control as one of the main components may make the Brahmaputra-Ganga link more feasible.