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Dear Erik 1. One query would be whether you could be getting contamination from the water you are using for jetting? Are the wells chlorinated after construction? There is a lot of pipe handling during construction, but I guess that would not lead to prolonged contamination. Is the contamination appearing immediately or only after several months? 2. How deep is it to the water table? 3. Do you have access to good dense local clay, because this would make an effective low cost seal with concrete above, combined with an apron, drainage and proper ground compaction 4. PVC slotted pipe can be used and you can make very fine slots (from memory around 0.2mm is the minimum but needs good equipment) or make bigger slots and wrap with cheap geo-textile, with rope underneath to maximise the intake area. It would be good to know what you are using at the lower end of the pipe - A ball, a blank- end screwed or bonded on or nothing?, If it is blanked off it is more difficult to jet with small slots, but if it is not, and no ball, the sand will slowly fill up the screened section over time. You can of course buy both stainless steel and plastic jetting points but these are not such a cheap solution. Best wishes Sally
Dear
Erik 1.
Erik
- One query would be whether you could be getting contamination from the water you are using for
jetting? Are the wells chlorinated after construction? There is a lot of pipe handling during
construction, but I guess that would not lead to prolonged contamination. Is the contamination
appearing immediately or only after several
months? 2.months? - How deep is it to the water
table? 3.table? - Do you have access to good dense local clay, because this would make an effective low cost seal
with concrete above, combined with an apron, drainage and proper ground
compaction 4.compaction - PVC slotted pipe can be used and you can make very fine slots (from memory around 0.2mm is the
minimum but needs good equipment) or make bigger slots and wrap with cheap geo-textile, with rope
underneath to maximise the intake area. It would be good to know what you are using at the lower
end of the pipe - A ball, a blank- end screwed or bonded on or nothing?, If it is blanked off it
is more difficult to jet with small slots, but if it is not, and no ball, the sand will slowly
fill up the screened section over time. You can of course buy both stainless steel and plastic
jetting points but these are not such a cheap
solution.solution.
Best wishes Sally