Mangaluru: Indian Institute of Science Professor T G Seetharam proposed a new technology termed Sea based reservoir to solve water woes during summer in the coastal region.
Talking about the same in the city on Tuesday, Professor T G Sitharam , an expert in energy and Mechanical sciences from Indian Institute of Science listed innumerable benefits from the project widely employed in countries abroad.
Claiming 120 TMC of flood water runs off to the sea, Prof.T G Sitharam said, the city of Mangaluru with five lakh population requires less than one TMC of drinking water every year considering a healthy average use of 150 LPCD.
Benefits
Major benefits include, flood water which flows into the sea is captured, which is otherwise considered wasted, without causing any damage to environment, river course and marine life. Opportunity to breed fresh water fish in the sea bed reservoir is an added advantage, Prof Sitharam noted and added, new fishing harbours can be built along the sea walls in the deep sea.
Floating solar water panels in shallow waters is possible, he claimed which will augment energy generation and water sports can be promoted in the reservoir, he stated.
Cost implications
Talking of cost implications, he said the project cost will be cheapest when compared to inland reservoirs, inter-linking of rives, recycling and desalination plants among others. He said it would cost around Rs 3500 crore to build a 25 TMC coastal reservoir and Nethravathi sea based reservoir alone can cater to the needs of the entire state which requires 90 TMC of drinking water annually. It would cost Rs 2-3 per 1000 kilolitre excluding pumping cost whereas inland reservoir will cost Rs 30-100, desalination 50-80 and recycling 100-110 respectively, he continues justifying positives.
He talked of innumerable projects successfully executed in countries including Netherlands, South Korea, Hong Kong, Japan and Singapore and drew parallel with our own Kundakulam Nuclear plant project which uses an equivalent sea based reservoir system for its nuclear power plant fresh water requirement. He went on to add Saemangeauam Sea wall in South Korea and Wadden sea project in Netherlands as most successful and large projects respectively having 32 km span but termed Marina Barrage project in Singapore as the Game changer .Marina barrage project gave a fitting reply to Malaysia which was arm twisting Singapore over fresh drinking water supply.
Efforts were made in India too at Kalpasar situated in Gulf of Kamabth,Gujarath. Nethravathi estuary provides ideal setting to implement the Sea based reservoir project In Karnataka and the professor with like-minded people dreams of interlinking all coastal reservoirs in what is termed as “Sarovar Mala”
He appreciated the initiative of BR Shetty group for evincing interest in promoting the concept as well as executing the project if government accepts the proposal. Prof. Sitharam mooted PPP model for the success of the project taking clue from National Highway development. He said Yettinahole project will not be feasible with deficient rainfall in the catchment areas of Sakleshpur (Yettinahole orginates here) over the years and said a shift in the rainfall pattern indicated more rain in coastal belt in the recent past
Briefing on construction, Prof. Sitharam explained that a coastal reservoir can be constructed using both a primary and secondary barrier. The primary barrier (using tetra pods) can be high enough to be above the tidal and wave height of the ocean/river/bay of unwanted water. It also can be strong enough to withstand the forces imparted on the wall by wave and tidal actions. The secondary barrier is a floating barrier (geo membrane) that has a skirt suspended from it. The skirt can extend to the floor of the reservoir and can be weighted with ballast to fix it. It can also be moved with an anchor and chain system. The purpose of this is the buffer zone can be varied in volume to allow for the volume of contaminated fresh water and keep it separated from the uncontaminated fresh water as shown in the diagram. The reservoir is filled by either allowing fresh water inside through a gate system during times of freshwater flows in the river, for example flood times; or by way of a conventional catchment system where the coastal reservoir is positioned correctly so that it is fed by catchment inflows. Coastal reservoir can be designed in such a way that it can be adapted to different locations without blocking off entire rivers or lakes, thus not disturbing environmental flows or leaving the waterway.
The chances of water getting mixed at sea bed are remote as the density of sea water is higher compared to fresh water, Prof Sitharam said and added that preventing the entry of salt water into fresh water was a ‘challenge’.
Total package
The industrial belt in the coastal region would benefit the most as it will not face any fresh water shortage when project is completed. There is a need to educate the fishermen on the project as they are likely to feel threatened (fisherman staying round the project site are likely to feel the pinch for 2 years max) project site for a while but will be the biggest beneficiaries after the completion of project as they will be able to venture into deep sea fishing, professor concluded. There will not be any dearth of sand for construction actvity and infrastructure development ,he stated.
Prof. Sitharam has made similar presentations to an audience comprising the State Chief Minister and technocrats some time ago. Recently he addressed a gathering in NITK, Surathkal and a body of 150 civil engineers from the coastal region in Mangaluru explaining briefly about sea based reservoir project. He remains hopeful that his proposals will help in eliminating summer water woes in the coastal region while offering technically feasible, economically viable and environmentally sustainable solutions in the long run.
