Sudden Drop in Borewell Yield : Remedy Sought! Bellandur, Bangalore.
Submitted by sarath_cs on February 21, 2010 - 09:20
I live in an apartment complex in Bellandur Bangalore. This area is thick with apartments and everyone has borewells. One of our borewells with a depth of 913 ft has suddenly dropped in yield. We had a yield test done a 15 days earlier and as per the report the static water level is 450 ft. This borewell is the main source of water to the apartment buildings and the drop of 30-40% is a significant impact. What actions/checks would you recommend? Should we inspect the pumps of the borewell? Is it safe to lift up the pumps - an earlier borewell a few feet away collapsed and some of us are worried about the risk of damaging the borewell.
thanks again for your support.
regards,
Sarath
Comments
1. Sudden Drop in Borewell Yield
Dear Sir,
The information provided for this kind of site specific problem is technically very less feeble to suggest appropriate and correct methodology. However without going into much details, to enhance yield in the same bore well, if you can offer, you can opt for multi hydro-fracturing methodology. As it looks your bore well is surrounded by fractured zones at deeper levels.
May be some of the main fractured conduit might not have been feeding into your bore well fractures or some other bore wells are sharing your fractured conduits and they might be sucking your water owing to their geo-positioning advantage. Might be.
Alternatively if you have enough space you can trace the main fractured conduits and drill new deep bore wells. This is an alternate solution. When hydro-fracturing technique was not known or are not getting adopted in the Trichy and Coimbatore belt, many bore wells recommended close to such kind of low yield bore wells have given surprisingly higher yield at depth levels of 250 feet during late 80s, in Trichy belt and depth ranges below 950 feet in early 2000s in Truppur and Coimbatore belt. The distance were hardly 5 to 8 feets away. But your terrain has soft formation at shallow depth and some time at intermediate depth and bore well may collapse as you informed. If it is hard strata then new one is better.
I would advocate for hydro-fraturing technique which would be available at Bangalore.
To sustain the yield rainwater harvesting with appropriate designs have to be carried out not only by you but also by your neighbours. Please consult a good rainwater harvesting planner at your place and follow the latest design and technological advents.
With best wishes,
A. Raja Mohamed Ambalam
Geophysicist
CEPL, Chennai
bismi1234786@gmail.com 09443619352
A. RAJAMOHAMED AMBALAM GEOPHYSICIST COASTAL ENERGY Pvt Ltd, CHENNAI +919443619352
2. sudden drop in yield
Dear Mr Sarth,
Couple of reasons for something to happen.
1) Some one else has drilled a new well that is affecting the yield.
2) You may have struck a huge pocket/cavity which is connected to the main aquifer but the connectivity is not very good hence initially you got the excess water and then it reduced.
3) The pipeline my have developed a leak, probably where the pipe is joined to the pump and due to this the pump is unable to develop the required back pressure to deliver adequate water to surface.
4) If you have a 3 phase motor you have a phase revesal and the motor is rotating in the reverse direction.
Ideally I would suggest the following-
Check if some one else has drilled a new well recently in the area.
Check if the amount of current drawn by the motor (ampere) goes up and the motor shuts off due to overload if the pump is switched on keeping the delivery tap closed. If it does not shut off then there is a leak in the pipeline.
This needs to be done only if you have a good quality control panel with overload safety shut-off.
You can always, pull out the pump and pipeline for inspection.
Hope this is helpful to you
regards,
Dr. Anil Lalwani
www.wellwaterworks.com
3. Sudden drop..
Thank you Mr Ambalan and Dr Lalwani for your responses. We are in the process of performing hydro-facturing on another borewell and will do the same for this well at some point (since we depend on this borewell at this time).
I will send out an update after performing the checks mentioned by you.
thanks & regards,
Sarath
4. contacts needed
Hi Sarath,
I stay in an apartment in LBS Nagar area and we are also facing the same issue as yours.
Please can you provide me the contacts for yield test and hydro-facturing.
Regards
Gopan
gopan.nair@logica.com
5. Dear Mr Gopan and Mr Sarath
Dear Mr Gopan and Mr Sarath,
Can I request you for an update on whether water situation in your apartments could be improved by taking some steps?
Regards,
Vin
vinst1@yahoo.com
6. Borewell pump trips
Hi,
We have a 600ft deep borewell with 2Hp TECHMA pump in our house (installed in 2009). Immediately after digging the borewell we did hydrofracturing as the yeild was poor.
The bore has been working very well and we have had uninterrupted water supply for the last 1-1/2 years. However for the last 10 days the bore pump is tripping. The pump draws upto 18/20 amps of current (It used to be 15amps when it was working properly) and the MCB trips after about 5-10 sec. There is no water pumped before the pump trips.
Can you please let me know what could be the possibe issues. Does the pump draw more current if the bore is dry. Could the motor blades be stuck, etc..? Can any wiring issues (like cut wires) lead to overload? Is there anything I can try before pulling up the motor assembly for inspection?
Regards,
Harish. S
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