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November 02

Doing a water resource study

Determining water availability for the city

- in conversation with Carel

The lake of Irumbai has dried up except for a few centimeters of water from unexpected pre-monsoon rains. There should be 60-90 centimeters of water after a good monsoon.

"Is there enough water for the city?"

This harrowing question was tabled in the Development Group about six years ago. "None of us was able to give an answer beyond 'we should do a study', and hardly anybody had an idea about the parameters," recounts Jan. "A water expert from New Delhi was visiting Auroville at the time. He helped us to formulate the Water Research Project and calculated the costs: about Rs 18 lakhs, way beyond the meagre budget of the Development Group. We shelved the project, but the idea stayed very much alive. Friends from the American Foundation for World Education (FWE) kept urging us to start, but they too lacked the financial means to support the project.

"It changed in 1999 when the Gateway group started its work of allocating a $ 1 million donation to various Auroville projects. The Water Research Project was dusted off and re-worked with the help of another water expert, the Israeli Dr. Israel Gev, who was visiting Auroville for a holiday. Then the FWE and Gateway agreed to co-sponsor the project to an amount totalling Rs 15 lakhs. Dr. Gev had indicated that Rs 15 lakhs would be sufficient for a study based on existing data but that there would be no financial scope for drilling exploratory bore wells or doing electro-resistivety or seismic tests to determine the geological formations accurately. The Development Group nevertheless decided to go ahead and appointed me as project manager. Three experts, Dr. Chamanlal Gupta from Pondicherry, Harald Kraft from Germany and Piero from Auroville, agreed to act as advisory team.

"The project started in February 2000. The first thing to do was the delimitation of acceptable boundaries for the research area. We finally agreed on Kalliveli tank to the north, the ocean coast to the east, and the Gingi river to the south and west. That determined a rather big area of about 650 square kilometres.

"Then we started the data collection, and almost immediately ran into a rather solid wall. I thought that we could obtain data by just nicely asking for them, but that proved to be an illusion. It started with PASIC, the Pondicherry Agro Services Industrial Corporation, which has drilled almost all the deep wells in Auroville. They have reasonably detailed files on most wells they have drilled in the last 10-15 years, including their depths, yields and qualitative descriptions of the extracted drill material. The latter gives an indication of the geological strata. But it took a year of intense talks before they allowed us to make a complete copy of all these files. Thanks to PASIC, we have now invaluable records of 216 wells in Auroville's city, greenbelt and keyhole areas.

"Apart from PASIC, we got well data from private drilling rigs and from the Sugar Mills Department that had sunk wells in the northern part of the research area. But none of their data were as complete as PASIC's. We also approached the Central Ground Water Board. They have drilled some test wells in the area, but until now they have not shared their data. At present we are in the process of asking them to allow us to monitor their wells.

"The next problem was to create a base map. The maps that are publicly available are on a scale 1: 250,000, which are unsuitable for our purpose.

But maps on a scale 1: 50,000 or 1: 25,000 are classified. Just when we had managed to obtain copies of these maps, with the invaluable help of the Secretary of the Auroville Foundation, we learned that an institute in Bangalore (ISROE), which was doing similar work on a national research level, had received official notice that they were forbidden to use these maps for their work. We had to drop the idea, and there was no other option than to use a Global Positioning System. (GPS)

"This sounded easy enough. We subcontracted this work to the Pondicherry based organization FERAL (Foundation for Ecological Research Advocacy and Learning) but they ran into unexpected difficulties. GPS is achieved through Satellite Positioning, but due to Auroville's close proximity to the Equator (and most GPS satellites are in the Northern Hemisphere), more often than not the satellites were too close to the horizon. In consequences, half of the coordinates lacked sufficient accuracy and needed re-surveying. Then the GPS equipment broke down. What should have taken three months again took over a year.

"Nevertheless, what resulted is the most valuable result of the water study so far: a base map as an accurate reference. It was overlaid with a grid satellite image and shows not only road patterns, the true extent of the surrounding villages, Auroville settlements and even big trees, but also the land use patterns of the area such as mixed forests, sugar cane plantations, peanut fields and cashew topes which is very relevant for the project - and of course all the wells, referenced in x/y/z coordinates. When we superimpose the results of the Auroville land surveys on this map, there is a complete picture.

"Auroville's unit Water Harvest and Pondicherry and Tamil Nadu Government Departments provided us with meteorological data. Interestingly, some of the oldest data came from Auroville itself, recorded in the small meteorological station set up in Certitude in 1969 by Chamanlal Gupta. It operated for a number of years, measuring temperature, sun-intensity, relative humidity, wind speed and rainfall.

"In all, it took two years for data collection and the creation of a base map instead of six months as projected. So we are way behind schedule. But with what is available today, we can go for the next step."

That next step has meanwhile been taken. It involves the Pondicherry Engineering College. Its Department of Civil Engineering is scrutinizing the collected data and has agreed to make the first "static model" of the hydro-geological situation in the area. This model will show the pre-monsoon, post-monsoon and dry season situation, and will allow to a certain extent the prediction of the water availability.

But the big challenge is to develop the "dynamic model" which could serve as the basis for making long-term assessments of water availability and could answer questions such as "what happens if the water draft is increased by say 500%. and we get a succession of 2 dry years?" Developing dynamic models is state-of-the-art in the West where highly sophisticated programmers do computer simulation. "In India there is ISROE and there are Indian Institutes of Technology (IIT's), but it may be difficult to get experts with real experience," fears Jan. "Moreover, we need to get the expertise and training ourselves so that over the years the model can be improved and modified as per our needs and we can run our own types of scenarios. But that's for the future."

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