groundswell development project

To manually drill a well you need a location to drill, materials to build the well and pump out of, and people to participate in the labor intensive drilling process. No machines are used to drill this type of well, making it an easily replicable, simple and sustainable technology.  The technology is a simple manual hydraulic percussion technique that uses lightweight inexpensive materials which are sourced locally, thus reducing the cost of the project while supporting local businesses.

This specific technique of manual percussive well drilling was pioneered by Terry Waller and North American Baptist missionary of Water For All International (WFA) and perfected over the past 3 decades of its use in Africa and Bolivia. Waller created this “Baptist” method of drilling for use in developing countries to empower and improve the lives of rural people living in poverty. It applies some of the same principles used in mechanized commercial well drilling, but does so using the simplest, most available and cheapest possible materials.

The following is a basic overview of the process of manual well drilling: 

An open hole is drilled down into the ground using a ball and dart point bit on the end of a 3-6 meter 1.25 diameter drill stem made of galvanized steel.  As the drilling advances, additional sections of 1.25diameter PVC drill stem are added to increase the depth of the well.  The top of the drill stem is attached to a rope, which is threaded over a pulley on the top of a tripod and a team of 4 to 8 people, depending on the depth of the borehole and weight of the drill stem, pull the rope and assist in the drilling process. The ball and dart point act as a foot valve.  

As the ground beneath is pounded, the “cuttings” or small pieces of rock, stone, sand, clay enter the drill stem through the drill bit.  The cuttings are forced upward through the pipe and are discharged at the surface into a settling pit. The hole being drilled is kept wet with water and bentonite is added to prevent wall collapse.  The cuttings are monitored periodically throughout the process of drilling and once you hit stones that look water washed, you’ve most likely hit an aquifer.  After hitting water, the drill stem is removed, the well is cased using 2 1/2 inch PVC pipe which is counter weighted with water to prevent buoyancy caused by mud in the hole.  Pipe is added for the casing until the bottom of the hole is hit and then the casing is tied off to something heavy to keep it in lace over the well.  

Once the casing is in place the well is “cleaned” and all of the remaining mud and bentonite are pumped out using water and a backwash pump.  The well then must be hand pumped until the water begins to clear up.  The well is then considered “swabbed” and a hand pump may be installed and its now ready for use.

How do you know where to drill?

A suitable location to drill is based on three basic criteria: water table depth which should not exceed 60 meters, suitable geologic formation for percussive drilling and the interest and participation of local people.  Once these criterial have been satisfied, the drilling process can begin. 

10 families are selected and prioritized with the help of local partners and a wait list is established for those who are not selected as the first ten. Of these families, one person is responsible to attend, participate and share the training they receive from GDP. Each of the 10 participants agrees to ensure the drilling of a single family well for the other in the group.  Once the agreement is made a 2 day training session takes place.  Basics of groundwater extraction and local methods of water collection are discussed as well as public health and hygiene. 

Once the first 10 are trained, supplies are purchased in a local market to construct the manual drill rig, well and pump. A welder can make the drill bits using: bolts, couplers, and the leaf springs from repaired cars. The technology is a simple manual hydraulic percussion technique that uses lightweight inexpensive 2 1/2-inch plastic PVC pipe. The PVC pipe is threaded onto a length of 2 1/2 -inch galvanized metal pipe that is fitted with the homemade bit with an internal check valve.

What exactly is manual percussion well drilling?

The percussion drill is one of the oldest known tools for making holes in the ground to get water. Records show that it was used by the Chinese in 1100 BC and it still is a very popular method of drilling today. The early percussion drills used strips of bamboo tied together with a heavy metal weight on the tip. This tool was lifted and dropped by many men working together, sometimes for years, to chop a hole from thirty to three thousand feet deep. Today's giant drilling trucks use steel cable, long steel bits weighing up to several thousand pounds, and have rugged diesel engines which raise and lower the tools quickly and easily--so that two men can drill hundreds of feet by themselves in a matter of days.

Between 1100 BC and today,  there have been many variations of the percussion tool, but the basic design has remained the same. For most types of soil, the percussion drill is a solid, reliable, and fast way to make a low cost well. As a simple technology for developing countries, the percussion drill is ideal. The drill design is adaptable to whatever level of technology is available. It can be made from scrap steel and carried into remote, road less areas. It can be powered by a dozen men pulling on a rope, or by a system of levers and springs, or by an automobile, or by any size engine mounted on a truck bed. A driller trained on one system can easily adapt to any one of the others, thus allowing simple drilling programs future expansion possibilities.

Percussion drilling is easily learned and can be practiced without much formal training. In the case of the simpler hand-powered systems, a full drill can be constructed from $100 to $200 in easily designed tools and free or low-cost local materials (like poles, sticks, twine, etc.). So it is possible to train local craftsmen to be drillers and for them to equip themselves inexpensively. Also, since the tools can be used to drill numerous wells before needing replacement, the driller can work locally at a wage rate that can be afforded by his community, supplying the much needed economic incentive that can both attract and hold craftsmen to the business of water development.