Plans for Borewell Implementation: Suggestions sought - Haryana
Submitted by iwp on April 20, 2009 - 23:49
I am planning to drill a borewell for my farmhouse in Haryana. Currently the water level is at around 80'. Water level information is based upon previously drilled bores in the area and quite consistent. The water requirement is to irrigate 1.5 acres of vegetable patch. I hope to be able to obtain about 10 m3 / hr so daily requirements should be met with average running of 2 hrs +/- 1 hour.
For this local boring companies advise the following:
- To bore down to 180' with the pump at 130'.
- To use 7" PVC pipe for casing the bore and 2" PVC pipe for pump discharge.
- Additionally they advise using 7.5 HP pump for the bore.
In the light of the available information regarding the water source will this be advisable? Do pass on your suggestions.
Vaibhav Sareen
Comments
1.
Dear Vaibhav Sareen,
The driller should maintain drillers log and collect soil/rock samples from at 2m interval and also note down depths at which water was struck and corresponding discharges over "V" NOTCH which any standard professional drilling company/Private driller would install as part of drilling equipment. The final "V" Notch reading taken after flushing the bore well for sufficient time (minimum three hours and more if water continues to be muddy) gives fairly good idea of the final yield.
Pumping test needs to be done for designing the pump set (safe discharge, allowable draw down, depth of installation of the pump and recovery period).Step draw down test (minimum 3 steps, each step of at least 100 minutes duration, at different discharges) followed by recovery measurements (after stopping the pump) till the pre -pumping water level is recovered should be conducted to determine the above parameters.
Horse power can be determined after looking at the pump characteristics (should be available with pump manufacturers/qualified dealers). AFPRO, D Block, Janakpuri, New Delhi will be able to provide on site guidance.
What is the horse power of the pumpset in the neighborhood and at what depth did the neighbor install the pumpset? Such an enquiry would be helpful.
Not only the diameter of the PVC pipes but also pressure ratings should be specified-minimum 6 pounds per square inch. Only ISI marked pipes should be purchased.
With regards,
C. Udaya Shankar
Geologists
2.
Dear Vaibhav Sareen,
As you say that the water is available at 80ft in your area, You really do not need to go down to 180ft today.
In the present day conditions it would be enough if you drill down to about 130-140ft. ( about 50 to 60 ft below the water level in your area)
But if the water level drops due to excessive pumping and more and more borewells being drilled in your area then you will face a problem.
If Money is not the constraint then I advice that you plan for future and drill a deeper well say 200ft.
As regards the Pump well You could use a 1.5 inch pipeline ( 40mm) and lower the pump down to atleast 110ft .
You really do not require a 7.5 hp pump
with this kind of low head even a 3 hp pump will deliver anywhere between 9000 to 14000 liters per hour. This depends on the model and the impeller design you go for.
A pipe size smaller than 40 mm will only increase frictional losses but as the total length of pipeline is not much even a 1.25 inch ( 32 mm pipeline ) would work, probably with the same pump one would expect to get a slighter lesser discharge.
I hope I have managed to help in making the proper decision to meet your water requirements.
Regards
Dr. Anil Lalwani
http://www.wellwaterworks.com
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