I am writing to seek the advice and suggestions of experts on bore well drilling in this forum. We have recently acquired a 60+ acre agriculture land in near Kuttralam [15 Kms from Kuttralam] Tenkasi Taluk, Tirunelveli District very close to the Kerala border. The property is at an elevation of 220 MSL, and we share a common boundary with the Reserved Forest Hill range [These hills are part of the Southern most part of the Western Ghats]. The land is currently barren with some teak, cashew and Amla tress that have not been maintained nor received proper irrigation [with the exception of rainfall] over the last 7 to 8 years. This location does not have a well or a bore well.
The land is set amidst well developed coconut groves and farms.This location received above average rainfall. With its proximity to Kerala [the border is only 4 Kms away] at times we receive Kerala’s South Western monsoons between June to August and Tamil Nadu’s North Western Monsoons [the main monsoon] between late October till early December.
Nearby farms have open wells and bore wells. Ground water availability does not seem to be a major issue with continuous supply of water in open wells that have been dug between 40 feet to 65 feet, and bore wells that have been drilled anywhere between 150 to 600 feet within a 1 Km radius.
We conducted a thorough Ground Water survey through a Geologist, who used an Electrostatic meter to survey the property and his observation was there is good ground water availability, and that we should go for a combination of bore wells and open wells. We wanted to initially drill 1 bore well as a trial, and the geologist marked 1 point and recommended that we drill only till 150 feet, but also mentioned that we can go to depths beyond 150 feet to experiment for the 1st well.
Based on point identified by the geologist we drilled a 6 inch bore well in 1 point, we hit the hard rock at 63 feet, and lodged the outer casing at 63 feet. At 90 feet we struck water and we had very good force sufficient for a 2 inch pipe output between 110 feet to 150 feet. As per the geologist’s advice though we wanted to stop at 150 odd feet, we were advised by the neighbouring farmers & locals to go beyond 150 feet as there would be plenty of water availability below 300 feet. Based on the advice received from the borewell operator we did not provide an opening in the outer casing pipe to tap the surface water as their logic was there is more water available at depths. We proceeded based on local advise. We hit a single rock at 63 feet which kept going down till 450 feet, From 200 feet onwards till 450 feet we just keep getting grey rock powder. We stopped drilling at 450 feet though there was a suggestion from neighbours to drill till 600 feet, but with no information and data to back us on the depth of the rock, we stopped drilling, at that depth there was no water and we called off a disappointing bore well drilling operations.
Post drilling over the next 2 days, we checked the water level for 2 days consecutively inserting a rope till 100 feet, there was no water till 100 feet. Subsequently we hired a 5 HP motor and used Air Compressor to check availability of water, despite trying to pump using the Air Compressor, there was no water.
Every pump supplier; bore well operator; neighbours; locals and the geologists all claim that there is plenty of water in and around our property. The geologist has asked us to treat this as an experiment and dig an open well in the location where we drilled a bore well. We went and personally checked all open wells and bore wells in the neighboring locality, most of them running on 5 HP and 7.5 HP Motors with plenty of water.
I would like to seek the advice of experts in this forum on the following areas
- How can I salvage this borewell and tap the surface level water, there was water equivalent to 2 inch pipe output between 110 feet to 160 feet, which we had sealed and not provided an outlet for?
- Is there any merit in drilling beyond the 450 feet, where we stopped drilling?
- Should we go for open wells instead of bore wells?
- What is the failure rate of an open well?
- How does one obtain drilling data, the bore well operator was not communicative or informative and his machine / truck did not have any information panel
- Are there sophisticated bore well machines that can provide drilling data?
- Who does one identify the depth of the rocks under the surface and the depths of possible streams?
- Are there any advanced scientific methods for identifying ground water availability; underground rocks and streams?
- Where did we go wrong in our drilling and what steps should we take when we drill in the future?
This is a very long message with several questions. I shall appreciate the advice and suggestions of the experts in this forum
I look forward to hearing from you
Kind regards
KRISHNAN P S
CHENNAI