Deepening Hand Dug Well

1. Deepening Hand Dug Well: Under Lining

Underlining using bricks

 

 

 

 

 

 

Underlining using cement blocks. Starting with the first block

 

 

 

 

 

 

After the first ring is ready, a second ring is mounted underneath.

Description

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

Advantages compared to cement rings

  • – No need for transport of moulds or   cement rings
  • – Can be made with local bricks or cement blocks
  • – Can be made in any diameter well
  • – In most cases cheaper

Disadvantages compared to cement rings:

  • – If rings are available it takes more time
  • – Only possible until the water layer .(can go on when water is pumped out or taken out with buckets)
  • – Need high quality bricks, so bricks do not crumble in water over time

Information

  • Under lining need to be made with good quality (high temperature burnt) bricks
  • No need to put cement between the brick layers, just a bit in the corners
  • Can be installed in any size of well
  • Cost indication 20 – 40 US$ /Per meter
  • Producers: Info at all SMART centres

2. Deepening Hand Dug Well: Well pipe

Using the Well pipe system to pump out sand, gravel

 

 

 

 

 

 

Sand is pumped out inside the PVC pipe by moving the Tube bailer up and down.

 

 

 

 

 

 

Sand and gravel removed by the Tube bailer

 

 

 

 

Description

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

Information

  • 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
  • Cost indication for a 2 m long screen, 4 inch : 40 – 200 US$ (incl. filter screen)
  • Producers; Information at Mzuzu SMART Centre
JasminaDeepening Hand Dug Well