Well Construction

A hand-dug well provides a community with reliable, year-round access to groundwater without requiring pumps or pipes. Done correctly, it is one of the highest-return infrastructure investments a settlement can make.

Key Concepts

• —Aquifer identification: wells tap unconfined aquifers in permeable sand, gravel, or fractured rock layers that lie above an impermeable clay or bedrock floor; local geology determines feasibility.
• —Well siting: locate upslope from latrines and waste areas, at least 30 meters from any contamination source; identify natural drainage patterns to avoid seasonal flooding of the wellhead.
• —Lining and casing: the upper 3-5 meters of a well must be lined with mortared brick, stone, or concrete to prevent surface water infiltration; below that, unlined or perforated lining allows groundwater inflow.
• —Hand-digging versus augering: hand-digging works in soils where workers can stand in the hole; a hand auger extends reach in stable soils and reduces the hazard of confined-space work.
• —Wellhead protection: a concrete apron at least 1 meter wide surrounds the casing and slopes away from the well; a cover, a dedicated bucket, and a drainage channel complete a protected wellhead.

Practical Guide

1. 1.Survey the site by digging a 1-meter test pit; if soil is damp at that depth in dry season, the water table is likely within reach; consult neighbors about existing well depths.
2. 2.Dig in shifts of two people: one excavates at the bottom while the other hauls soil in a bucket using a rope and pulley rigged from a tripod of poles above the opening.
3. 3.As you dig, line the upper sections with mortared brick courses, building the lining from the surface downward and undercutting it to sink as digging proceeds - the underpinning method.
4. 4.Stop digging when water inflow exceeds the rate of removal, or when you reach at least 1 meter below the water table to ensure year-round yield even during dry season drawdown.
5. 5.Allow the well to recharge for 24 hours, then bail it completely dry three times to remove construction debris and sediment before using the water for drinking.
6. 6.Pour a concrete apron around the casing extending 1 meter in all directions, sloping outward; install a drainage channel to route spilled water away from the well.
7. 7.Disinfect the new well by adding 200 mg of chlorine per liter of standing water (roughly 1 cup of household bleach per 1,000 liters), leaving it 12 hours, then pumping it out before use.