Agreement to drill water deep well at Chitlang signed between Madan Bhandari University of Science and Technology and Nepal best Drilling company and Lord Himalayan Construction Pvt. Ltd. The drilling site of well is located Taha Municipality-09, Chitlang, Makwanpur district, Bagmati province, Nepal. The drilling unit was mobilized on drilling site on 2079-06-06 after the site selection. The drilling was carried out to the depth of 174 meter by DTH method of drilling.
A down the hole drill, usually called DTH by most professionals, is basically a mini jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small flakes and dust and is blown clear by the air exhaust from the DTH hammer. The DTH Hammer is one of the fastest ways to drill hard rocks.
Based on drilling, litho-logical strata counter during drilling, drilling rates and other hydro-geological properties, the tube well was designed and lowered pipe to the depth of 174.5 m.
Pneumatic method of drilling was used for well construction. Drilling was done by 275mm bit – 0.00m to 104.0m
200mm bit – 104.00m to 174.0m
Total length of casing and screen used
200mm MS Casing Pipe – 78.5 m
200mm MS Perforated screen Pipe -24.0 m
150mm MS Casing Pipe – 59 .0 m
150mm MS Perforated screen Pipe -13.0 m
……………………..
Total length 174.5 m
0.5m of 200mm casing is above the ground surface.
The well was developed by high capacity air compressor to make water sand free more than 12 Hours. The compressor capacity was higher than the rated capacity for the development of the tube well. The well was free of sand and silt aper development.
GROUNDWATERPRODUCTION
Static water level -57.00 m below ground surface
Dynamic water level -66.10 m below ground surface
Discharge adapted for test-5 lit/sec
Transmissibility (T) = 1.47x 10-4 m2/sec
RECOMMENDATION
We recommend the client to develop the tube well (Cleaning of tube well) in every two years’ interval to maintain its original discharge and for better life of the well.