THE DIARY GAME : 25TH MAY, 2022 : UNDERSTUDYING BOREHOLE DRILLING FOR THE COMMUNITY OF NARELIGU | CLUB100
As part of our geological program, we undertake a series of hydro-related courses such as hydrology and drainage, engineering geology, among others. This is a vital part of our program since water is a significant component of life that cannot be neglected. As such, borehole siting and drilling is an integral component for accessing groundwater.
This is what we set out to do in the town of Nareligu today with our hydrology contracter and senior lecturer who took us through the entire process of community borehole drilling. This is a bigger version of the ordinary backyard borehole since it is meant to supply water to the entire community of Nareligu.
Before any borehole can be well sited for drilling to begin, there should be proper geophysical survey done in the area. This allows us to gain an understanding about the aquifer and water table within the subsurface.
Usually, the main target area for a community-sized borehole is the peripheries of streams. These are the best possible sites due to its well drained depths as well as the nearness to a recharge source (which is the stream). The drill rig was therefore sited at this location.
Once the drill rig is sited, we insert the drill bit as well as the tricorn bit. The tricorn bit is the tip of the drill rod or "blade" that is going to be drilling through the overburden. We keep drilling using the 5 meter drill rods till we reach the fresh rock down below.
As we drill further, metal casings are inserted to prevent the overburden from falling back within the borehole which is being dug. This also allows the drill drill to focus more on the downhole and avoid tilting.
Once we hit the fresh rock, we switched to a different bit (the diamond bit) which allowed us to drill further down the more coherent rock of the subsurface. We had to drill further before we could eventually strike the aquifer hosting the groundwater.
With the diamond drill bit, the drilling progresses down the subsurface until we finally strike water which would be quite evident as water will keep gushing out of the drill hole. Once this occurs, we stop drilling and insert pvc pipes.
Before insertion of these pipes, we first use bay plugs at the bottom. These are simply the anchors of the pvc pipes as they hold them firmly in place. After this, we add the pipes to allow the smooth flow of clean water.
After we struck water, there was so much joy in the community since they have been waiting for this particular project to be initiated for quite some time now. And at times, they were let down by the community leaders.
I was pleasantly pleased by the professionalism of all those who were present. There was a point in the drilling process where I saw the drilling consultant step in and help since they were a man short. That was quite spectacular from him.
This water still needs to be tested through lab analysis in order to really understand its purity and reach safe levels for community consumption. It was quite a learning experience for me and my mates. I can certainly apply this experience to supervise a potential project in the future.
Thank you for your attention.