When a well dries up in the dry season it can be made deeper with the so called Underlining method. With bricks or blocks one ring is made. A next ring is made underneath so the first ring stays in place.(does not go down like cement rings) In this way the well can be made deeper without collapsing.
An option to make wells deeper is the so called Well pipe. A PVC pipe with a filter screen is put at the well bottom. With a bailer on a tube, sand is pumped out and the PVC pipe (screen) goes down. In this way the well can made deeper 1 to 3 meter without collapsing.
Advantages compared to underlining
- Is faster
- Is cheaper
- Can be done with water in the well; no need to wait for the dry season
- Safer in wells that may collapse
Disadvantages compared to underlining
- Requires tools like a tube bailer
- Does not work in case of rock or boulders or gravel larger than 4 cm
- Requires skilled technicians
- Less storage capacity
When the screen is deep enough it is cut off 0.8 meters above the bottom and a “trumpet” is mounted to facilitate the mounting of a pump.
For wells over 6 meters deep, use a short Tube bailer and work at the bottom of the well.
PVC pipe (filter screen) can be 3, to 6 inch, depending on pump type
Cost depends on soil type, length of screen and diameter of casing