Thursday 30 June 2005
From: Claire de Boursac
Received by: Email.
Hunting for Water
When we were approached with this project, the school had a design and location for the well which had been approved by the previous contractors before they disappeared with the funds. The decades of irrigation in this area, combined with the rock types present mean that many of the local water sources are hard and saline. The likelihood that the well would produce salty water was high and although the villagers were unphased by this, having drunk salty water all their lives, the idea did not sit well with us. Aware that well construction is somewhat of a science and one in which Aid Sri Lanka is not an expert we enlisted the help of the country’s top hydrologist.
Dr Senaratne and his team of experts spent the afternoon mapping the unused land at the back of the school. They used advanced technology to survey the land, taking electromagnetic readings to reveal the location of water fissures underground and using GPS technology to record the exact locations for comparison with satellite pictures of the area back at the lab.
Even without the equipment they were able to suggest which sections of the site may be most suitable due to the rocks found at the surface. It was fascinating to watch these men at work, real experts.
Results of preliminary investigations
They were unimpressed with the original proposal, both in terms of location and well type. They located a point where three water fissures meet which should provide a good yield of water. In addition, the rocks here would indicate a good water quality although work back at the lab will provide more detailed information on this. The location is a good distance from school building so that classes will not be disturbed by the locals coming for water and not too far away from the school buildings for collection for school use.
The original proposal was for a shallow well, fifteen feet wide and twenty feet deep. We were concerned about this from the start. The large surface area increases the chances of contamination and there were concerns about the safety implications of an open well where children may be playing. The experts suggest a tube well. This taps water deeper in the ground. The system is fully covered to avoid contamination and water is pumped to the surface. It certainly seems a much more suitable for the location.
The experts will undertake further studies at the lab, including analysis of rock and water samples taken at the site. They will then design a detailed proposal for well construction. It should be possible to complete the construction during the summer holidays so that classes are not disrupted.