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Hi George and Barbara,

Faced with this challenge I would first check the water quality for faecal contamination. If it currently has <10 faecal coliforms per 100ml then you can be confident that it will have zero after the spring has been capped, allowed to flush out (2 weeks) and is properly protected from contamination. Physico-chemical analysis is important for due diligence. Any worrying levels will have to be addressed for the sake of health of the population. Quite how you can ensure that extraction for the school does not cause difficulty in drawing water for the local population needs to be addressed - the best way wold be to have a separate tank to buffer up a minimum volume for their use. Then you face the issue of pumping the water - always costly if using internal combustion driven pumps, always the biggest source of problems and a cause of much frustration. The source looks to be quite close to the school. One way to reduce the need for pumping would be to ask each pupil to bring a bottle of water to school each day. Not ideal but done in many places around the world. If you can supply the head difference between the school and the source along with the flow rate from the source we could see if a hydram is an option. This is a simple mechanical device that pumps water for free. Your concern about bacterial growth - if this is about algae then keeping the inside of the tank dark will combat that. Regular but not frequent cleaning and shock dosing followed by flushing out will keep the tank clean. This sort of maintenance has to be well managed and supervised - if the school is taking the responsibility then there is reason to hope it will happen - otherwise water committees are another issue. If the source proves to be emitting a lot of entrained sand particles or silt then you will need a settling tank prior to pumping and may need additional filtration at the school. If this proves to be the case then I would use a slow sand filter. Both the settling tank and the slow sand filter would need maintenance. The slow sand filter would have to be sited higher than the storage tank. OK I can see it's getting messy now ...

Best to do this a stage at a time. By protecting the spring you will improve health. Get a sample checked and go from there. This will indicate the turbidity, biological and other levels of contamination that need to be dealt with. Flow and heads would be useful to know now.

Reality check (for me): looking at the satellite image, the valley in which the 'source' sits has trees further up indicating that the roots are finding water regularly. The valley is there because of erosion so the water source is probably a point where the land falls away more sharply and the water table is breaking the surface. One thing you will have to be careful of is infiltration by surface water when the rains come and water flows down the valley over the capping - you will probably have to seal the top of the capping with concrete rather than the usual method of gravel and geotextile - a clay cap with a concrete overlay would be better.

Hi George and Barbara,

Faced with this challenge I would first check the water quality for faecal contamination. If it currently has <10 faecal coliforms per 100ml then you can be confident that it will have zero after the spring has been capped, allowed to flush out (2 weeks) and is properly protected from contamination. Physico-chemical analysis is important for due diligence. Any worrying levels will have to be addressed for the sake of health of the population. Quite how you can ensure that extraction for the school does not cause difficulty in drawing water for the local population needs to be addressed - the best way wold be to have a separate tank to buffer up a minimum volume for their use. Then you face the issue of pumping the water - always costly if using internal combustion driven pumps, always the biggest source of problems and a cause of much frustration. The source looks to be quite close to the school. One way to reduce the need for pumping would be to ask each pupil to bring a bottle of water to school each day. Not ideal but done in many places around the world. If you can supply the head difference between the school and the source along with the flow rate from the source we could see if a hydram is an option. This is a simple mechanical device that pumps water for free. Your concern about bacterial growth - if this is about algae then keeping the inside of the tank dark will combat that. Regular but not frequent cleaning and shock dosing followed by flushing out will keep the tank clean. This sort of maintenance has to be well managed and supervised - if the school is taking the responsibility then there is reason to hope it will happen - otherwise water committees are another issue. If the source proves to be emitting a lot of entrained sand particles or silt then you will need a settling tank prior to pumping and may need additional filtration at the school. If this proves to be the case then I would use a slow sand filter. Both the settling tank and the slow sand filter would need maintenance. The slow sand filter would have to be sited higher than the storage tank. OK I can see it's getting messy now ...

Best to do this a stage at a time. By protecting the spring you will improve health. Get a sample checked and go from there. This will indicate the turbidity, biological and other levels of contamination that need to be dealt with. Flow and heads would be useful to know now.

Reality check (for me): looking at the satellite image, the valley in which the 'source' sits has trees further up indicating that the roots are finding water regularly. The valley is there because of erosion so the water source is probably a point where the land falls away more sharply and the water table is breaking the surface. One thing you will have to be careful of is infiltration by surface water when the rains come and water flows down the valley over the capping - you will probably have to seal the top of the capping with concrete rather than the usual method of gravel and geotextile - a clay cap with a concrete overlay would be better.better. Incidentally - encouraging to see the big bamboo there - indicates that the water source is fairly constant.