Learning

1. Boreholes in North and Middle Andaman has not been very successful and hence not recommended as good groundwater aquifers are not found in the Islands except in very few igneous pockets of Mayabunder Island
2. Shallow bore wells though they deliver water in these places the yield has been poor because of the clay sub surface formation and very often fail during summer season
3. Bigger the diameter better the yield of open dug wells of about 6m depth this is also associated with the clay subsurface formation
4. Dug wells still remain the best source of water for the rural mass of the island however open defecation (lack of sanitary facility) remains a threat of contamination to such shallow open dug wells. (Port Blair doesn't not have a sewer system this wells here also runs risk of contamination)
5. One of the important reasons rainwater harvesting efforts by government has failed is because the dry period and size of storage is not taken into consideration while designing
6. Though no harmful chemicals found into groundwater some water sources have known to deliver iron rich water or brackish water. In many shallow wells the brackishness is due to the sedimentary rock formations rather than a saline aquifer.