Manual drilling uses local labor and locally made drilling tools to make tube wells. Practical and affordable solution for wells <40m deep in alluvial soils (loose material, such as clay and sand) and soft weathered rock formations (such as soft sand stone and lime stone). Wells can be made at a fraction of the cost of conventional drilling or lined hand dug wells. The 4 principles are: hand augering, percussion, sludging or jetting. All have their own advantages, disadvantages and applicability.
Costs of 30 meter deep manually drilled wells vary from about € 100 - 2500, depending on geology, country and application. The equipment for manual drilling can be locally manufactured, transported and maintained. Governmental or microfinance funds are typical for financing.
Preferably constructed through small-scale commercial drilling enterprises – instead of NGO’s – as this provides a more sustainable long-term solution. Key implementation action is organizing training and identifying local workshops for equipment manufacturing. Wells best managed at household- or community-level.
Location and soil formation analysis needed before borehole construction. A general rule of thumb is that if wells can be dug by hand (without dynamite), than wells can be drilled by hand too. Design needs to anticipate on low water levels during droughts. High contamination risk, e.g. from latrines or neighboring communities via diffuse water pollution.
Optimal method to a depth of 40m and a water depth of up to 25m. Quality of borehole is similar to mechanized drilling. Each sub-method requires a different set-up. All parts (e.g. drill pipes, drilling bit , rope) can be purchased or manufactured locally. The drill pipes and bits need regular repair and sharpening. All types of hand pumps can be fitted to a manually drilled borehole.
Low-income households, are often able to pay for a well that is drilled manually. Depths and quality of materials is in this case low. Use of groundwater reduces chance of multiple contaminations.
No relevant remarks for Manually drilled wells.
Akvopedia - Manual drilling general
SSWM - Drilled Wells
PRACTICA Foundation - Drilling & wells