Borewell drilling:- My Experience

[amohit]

Hi,

Last week we dug a second borewell for our apartment. Since I am a member in the managing committee of the apartment, I was directly involved in this task of drilling new borewell. In this thread, I will post my experiences of the whole process.
Hopefully this will help someone.

Let's divide the whole process into 5 stages.

Stage 1: Realization

Stage 2: Deciding on the point

Stage 3: Drilling

Stage 4: Cleaning up the mess

Stage 5: Getting the water

Stage 6: Future planning

Our apartment was constructed 5-6 years ago and we have 2 borewells for 75 flats. At the time when the apartment was constructed, there was no water shortage in our area (Basvanagar), hence our builder decided to go for only 2 bores at 450ft. Unfortunately, both the bores are 10-15 ft apart and at same depth. So when the things went wrong, both the bores went dry at the same time.

Stage 1: Realization-

In the summer of 2010, we for the first time realized that underground water that we had been pumping out so happily is not unlimited. One fine day our borewell just went dry. This happened in the month of June 2010. We then thought, never mind, lets call tanker guys. This was the time when we realized that it is easier to buy petrol tanker but not water tanker. Irrespective of how much money we were ready to throw, none of the tanker guys agreed to come. Reason:- They were already running at full capacity supplying water to other apartments. Then it dawned upon us that the whole area where we are located has become very dry in the last 5 years...all thanks to mindless drilling and pumping. Luckily for us, we finally managed to get 3-4 loads of water for 75 flats for the next few days. Within a week it started raining and our borewell again started functioning.
Two things we learnt from stage 1.
A. Water is very precious. (Its certainly not free as most of the ppl in my apartment used to think).
B. Rainwater harvesting. If regular rains can help us get water for 6-8 months harvesting all the water (and if done by everyone) will certainly help us in the long run.

Stage 2: Deciding on the point
We started putting in our efforts on two fronts. 1 was rainwater harvesting and another was to increase the depth of existing borewells. Rainwater harvesting project is still WIP (work in progress).

To deepen the existing borewell, we called some consultants. We came to know that since both these bores are situated in the basement, there is not enough space to get the drilling truck. We can do some gas pressure drilling but then it can be done only upto the depth of 500ft. Moreover it costs double of the regular drilling.

So then our focus shifted to drill a new bore. For this the first thing was to find a place to drill. A little research reveled that there are 3 prominent ways to do this.
a. A coconut guy.
b. A wooden L shaped rod guy.
c. A geologist.

and d. Some service based on gps points and satellite imagery of that location.

Among these, d is most scientific and most unreliable of all. ( take a hint from our weather forecasting services)

Among the remaining 3, (c) a geologist guy seemed to be the most scientific. However, under pressure from senior citizens and other wise men of our society, we decided to call in a coconut guy. He gave us 3 points. At the end of the day, the impression I got was, its all eyewash! He charged us Rs 500 for his services.

Next we researched for the borewell company. After a few consultations we finalized on Kannan borewells. We called them to visit the site and discuss the modalities with us.
There manager visited our apartment and we finalized on a date n time to start drilling. He also suggested a geologist to mark the drilling point for us. Costs for his services were Rs 750. Since it was not much and we were not very sure about the methods used by coconut guy, we decided to go the scientific way. The geologist's methods were a bigger eyewash when compared to coconut guy
However, he also suggested a point very near to our coconut guy's point.
Since all these points were in the general area where we anyway wanted to drill our borewell, we decided to drill at the point given by coconut guy.

Stage 3: Drilling

TBC....

[mramki_77]

Very useful and informative. Thanks Mohit for posting.

Thanks
Ram

[idlebrain]

@ amohit - Thanks for the informative post.

[amohit]

Continuing...

Stage 3: Drilling-
Drilling costs vary from location to location. It depends on the general nature of soil in your area. Price will also vary for the width of the borewell. We got the estimates for 6.5in bore only. We got quotations from 2-3 companies and the rates were more or less same.
Cost of drilling increase with the depth. The best quotation that we got was Rs63 for first 250ft and Rs10 increment for every 100 ft upto 550 ft. Then the increment is Rs20 upto 750 ft and then its Rs30 upto 1000ft. Max legal limit to drill is 1000ft. So the estimate was like

Rs63 0-250ft
Rs73 250-350ft
Rs83 350-450ft
Rs93 450-550ft
Rs113 550-650ft
....and so on.

Apart from this we need to pay for the pipes that will go into the bore. Putting in pipe is must for the first few 100 fts as this is loose soil and will slowly fall into the bore.
After that if the ground is solid enough you may not need pipe linings.

We finalized on the dates and gave the advance cheque around 1 week in advance. The drilling was scheduled for a saturday 6am and was supposed to take around 12 hrs to drill down to 1000ft.

Inline with its established reputation, Kanan borewell's equipment reached our premises only 18 hrs behind schedule!!

On saturday night, they just setup there equipment and left it as is. I must admit they do have an impressive array of drilling equipments...all automated!

The work started at sharp 5.45 am on sunday morning. For the first 100ft a 10inch drill bit was used. This was changed to 6.5 inch drill.
The loudest noise was made by the drill when it went thru the concrete surface. After this all the noise was from the generator.
At 5.48am a police personal from HAL police st was there at our gate...to collect his share ... very impressive..I must say.
He informed me that someone complained about the noise coming from our apartment. I informed him that as per supreme court guidelines we can do this work between 6am and 11pm. I know we are 15 mins early, but if you insist , we will hold the work for 15 more mins and then start. (PS: I have no idea of any such SC directive...it was just a fluke statement!)

Any way, he just demanded some tea money...which I handed over to him, but not before telling him that last month even I had complained about the noise made from a flat in opposite apartment and even after 4 hrs no body came to check it! His facial expressions were worth watching!!

Anyway, coming back to borewell drilling.

We hit the first signs of water at 120ft. Next hit was at 415ft and thereafter absolutely nothing

The water yield of borewell is measured in inches. A 1-2 inch yield is considered good for 4-5 houses. For big apartment complexes a yield of 4inches is considered good. Now, how is this yield measured. Borewell companies have a wooden board, with a V cut on one side. with all the water coming out..after a few hours of drilling, they create a dam kind of structure (using the silt that has come out) and put this wooden board at one end. Then they measure the height of water flowing out of the V. Hence the yield is determined.

Anyway, we drilled all the way down to 1000ft. The most confusing part was that for almost until 500ft the supervisor was telling us that what water we have got is nothing, at 600-700ft we will get a lot more. But then, when by 800ft we got nothing else, he started saying that the yield that we are getting is very good and he just cant help it as we have hit a rock formation, hence no water.

And by evening he was suggesting us that we must put in pvc pipes all the way down to 1000ft as the soil is kind of lose. The total estimate to put the pipes was Rs 140 per running ft. These were all contradictory statements, hence we decided to leave the things as is for now.

They finished there drilling work by 11pm, collected there money and left all the muck as it is


Stage 4: Cleaning up the mess:- Next task was to get a tractor guy to clean up the mess. It took them 6 loads to remove all the mud and slush. This will give you an idea of how much stuff come out of the bore...apart from water.

Stage 5: Getting the water up

This task took us to SJP Road.

Crompton Greaves, Kirlosker, V-Guard, Texmo are some of the favorite brands of the borewell motors available there. Each shop has there own favorite and will try to sell you one brand over the other.

Borewell motors, as any other electrical motor are either single phase or 3 phase. In layman's terms 3 phase motor will be able to give you more water per hr when compared to single phase motor. This difference is about 50% more.

2nd attribute of borewell motors is Stages. Each stage is capable of pushing up the water by 22ft and push the water along horizontal surface by 66 ft. Since we had decided to put our borewell at 600ft depth, a 40 stage motor was recommended for us.
Since our yield is not much, a single phase, 40stage motor is what we decided on. The expected output was 60lpm (liters per minute), with 1.5inch pipe thickness.

We decided to go for Texmo brand as this was the only brand giving us 2 yrs warranty. Rest all were 1 yr warranty.

Next is the pipe and wire. The defacto standard in wires is finolex 4mm sq wire.
Water pipes also come in various flavors. Quality of pipe is measured in kg/cmsq. A pipe with a strength of 12.5 kg per cmsq was recommended to us.
The price difference between a 8kg/cmsq and a 12.5kgpercmsq pipe is almost 100%, so this is one place where these shop owners will make a killing.

All the recommendations that we were following were given to us by a relative of one of the residents of our apartment. Hence, we trusted him fully. Rishi, Raksha are few of the prominent brands.

Motor costed us 21k. Pipe was at 70 per ft and wire was 73 per sq ft.

Another point to note is that all the prices quoted in SP road are pre tax. The shop owners are not in habit of informing you this until the bill is made..so always add 13.5% to whatever price they are quoting.

The motor was delivered and installed at our premises within 24 hrs.

Currently, it is taking our 20k lt sump around 5 hrs to fill up to 90%. So effectively we are getting around 3600 lts of water per hr. This is in line with the arithmetic told to us by the motor guy in SP road.

Stage 6: Future planning:- Rain water harvesting.
We intend to implement a complete setup by end of march this year. Will create a new thread on my experiences with that project soon.

Take care.

Mohit

[rewatcher]

Mohit,

Thank you so much for such a detailed and informative post ! I cannot tell you how much useful it was for me considering that I am going to get a bore well dug in my site next month.
Thanks again..

[dhanushmadhava]

thank you very much mohit,
this information is very useful..
coz i m planning for borewell in my site..

[mumah]

Few correction, Tax is not 13.5% , it use to be 5%.

[sam_m400]

Hi all

How do we know how much inches of water is coming 2 Inches or 2.5 inches etc? I heard there is V shaped object to measure ,but most of the borewell people says it is not available now days and drilling guys will tell about that well as only source to measure. Please do help me how do i measure how many inches of water is coming out?


Regards
Sam