New Pumps

For the new pump installation, we’ve been training local crews in a hand-drilling technique called “Rota Sludge.” We’re sticking to manpower rather than machines in order to make sure the community is involved and feels ownership for the well boring.

As shown in the figure, a lever arm is used to drive a drill bit into the ground. First, the lever arm is pumped downward. Then, it is released quickly upward so that the drill bit plunges into the soil. While the drill bit is in the down position, it is rotated so that its teeth chew and loosen the soil. The boring is flooded with a runny mud, a mixture of cow manure and water. The hollow drill rod is sealed as the drill bit moves upward and open as it moves downward. Therefore, the mud and loosened soil are pulled upward through the drill rod. As the boring progresses, additional sections are screwed onto the drill rod for deeper penetration. The mud also serves to seal the soil on the walls of the boring, so that it doesn’t cave in.

Each crew has six to eight members. One member holds his hand over the top of the drill rod, sealing it as it rises and opening it as it lowers, allowing the mud and loosened soil to splash out. The second member holds a wrench at the top of the drill rod, and rotates the drill rod when the drill bit is lowered. The remaining members pump the lever arm up and down. We worked with the team to help its members coordinate all of these movements and optimize progress. I tried to capture the movement in the video; I'm new at this, and you'll have to hold your head sideways to watch.

We also coached them in keeping a boring log, a record of the soil types (sand, silt, clay) encountered as they drill, as well as the depth of the water table. With this information, they can appropriately place the well screen, the openings through which water enters. In this case, they hit a clay layer from nine to eleven meters below the ground surface. Underneath the clay layer was fresh water: a confined aquifer. Therefore, the screen will be placed to draw from this aquifer, and sealed above it to prevent contamination.

As we worked with the team, I could see a transition take place as the drilling crew’s confidence increased. They no longer considered themselves “ditch diggers,” but rather skilled technicians who were collecting and analyzing soil data to design a good well. As their experience grows over the course of this project, I can see that they’ll be able to apply these methods in any setting. It’s heartening indeed to be part of building the capability and resilience of a community.