KOZHIKODE DEC. 10. Kerala's experiments in inter-basin transfer of water provide valuable lessons for all those supporting the proposed national water grid project aimed at easing drought conditions in water - deficit regions.
Inter-linking of rivers as contemplated under the proposed project is a mixed bag comprising advantages and disadvantages, according to E. J. James, Executive Director, Centre for Water Resources Development and Management (CWRDM).
Speaking to The Hindu today, he pointed out that going by the State's experience in this field, social, economic and environmental factors had to be studied in detail before any scheme for sharing of water by inter-linking rivers was implemented.
The State has a long history in endeavours to transfer water from one river basin to another to reduce intensity of water shortage in water-scarce regions.
One of the earliest instances of inter-basin transfers in the peninsular region was from the upper reaches of the Periyar to another river basin in Tamil Nadu across the Western Ghats. This was done by constructing the Mullaperiyar dam more than a century ago.
The validity of the agreement between the Government of India and the erstwhile Travancore State, for this scheme, is for a period of 999 years. This project helped the people of Tamil Nadu to not only irrigate fields but also generate power.
Dr. James said such a water resources development strategy had certain adverse impacts on the river eco-system.
While meeting the demand for water on one hand, it led to the deterioration of water quality downstream of the river. Salinity intrusion and pollution dispersion problems in the lower reaches of the Periyar arose due to non-availability of sufficient quantity of water for flushing.
The safety of the dam structure and inundation of the eco-forest system are also aspects discussed with concern in relation to this scheme for inter- basin transfer of water.
The experience gained from this scheme highlighted the need to give due weightage to social and environmental factors while planning and implementing such schemes.
An intra-State inter-basin transfer from the Periyar to the Muvattupuzha river for power generation in Kerala has adversely affected the downstream flow in the Periyar river.
But its positive effect has been that this transfer of water considerably increased the availability of water for the inhabitants of the Muvattupuzha basin.
Kerala has a tradition of sharing its waters through inter-basin transfer with neighbouring States.
As part of the Parambikulam-Aliyar project, water from the Periyar, Chalakudy and Bharatapuzha were transferred to the basins of the neighbouring State to meet its water requirements.
As part of the scheme, water is being transferred even to the Cauvery basin. It is also interesting to note that water from the Siruvani sub-basin of the Bhavani River is transferred to Tamil Nadu, especially to meet the water demand in the city of Coimbatore.
Complaints are rife that water from the upper reaches of some of the rivers flowing to the west like Chaliyar are diverted by Tamil Nadu from the upper reaches for meeting some of their demands.
Kerala has planned several projects for inter-basin transfers within the State to meet the demands of deficit basins within it.
Examples are the Mananthavadi project, and the Kerala Bhavani project which are multi-purpose projects to be realised through inter-basin transfer to meet the demands for power generation, irrigated agriculture and drinking water.
However, the Government of India and neighbouring States have been cold to these projects, presumably because these have a bearing in the raging Cauvery water dispute.
Experts in Kerala are of the opinion that the proposed projects like the Mananthavadi project in the Kabini basin will prevent salinity intrusion faced by some west-flowing rivers in the State, which is a major environmental problem facing rivers in Kerala.
They also believe the Vembanad wetland already suffers from lack of sufficient inflow from the rivers to flush out salinity and pollutants and any diversion of water could aggravate the situation.
The concept of long distance mass transfer of water is not new and has been practised in India for centuries. The western Yamuna canal and the Agra canal built in Mughal times are examples. Water has even been transferred from the Himalayas to parts of Uttar Pradesh, Punjab and Rajasthan.
However, there is a strong case for a national-level networking of rivers since the availability of monsoon rainfall in India is restricted to three to four months and because of the erratic distribution of the rainfall received.
This is true for Kerala also. The State has high rainfall areas in Idukki and Wayanad and low rainfall in the Attappadi valley. Interestingly, rainfall in Palakkad, rice bowl of Kerala, is less than the State average. The undulating topography of the State also caused run-offs of rainwater received to the sea and water scarcity in dry months. These factors also support the case for inter- basin transfers within the State to meet the requirements in water- deficit areas.
Water management experts believe there is only limited scope for transfer of water from Kerala to the eastern side. K. L. Rao, former Union Minister for Irrigation, a revered authority on water management who first mooted the idea of inter linking - lining Cauveri and Ganga way back in 1972 shares this view.
Dr. Rao is on record as saying that "it is often stated surplus water is available in Kerala and this can be diverted to prevent the water from flowing into the sea and to feed areas in Tamil Nadu. In view of the fact that the rivers are very small and its water required by Kerala, diversion is not possible".
As far back in 1982, the Central Government set up the National Water Development Agency (NWDA) to take up investigations and conduct studies to find out the feasibility of inter-basin transfer of water.
Dr. James said the State Government had conveyed to the NWDA its view that while considering inter-basin transfer of water, water quality problems downstream and the impact it would have on the ecology of wetland systems downstream should also be examined.
Source: Inter-linking rivers -- the Kerala experience By R. Madhavan Nair, The Hindu, Dec 11, 2002.:
