Comprises cheap, shallow wells with a typical diameter of 0.8-1.5m. Occasionally, a cover or a concrete apron is made for well protection. Risk of collapsing in wet season because of the lack of lining or when dug too deep into aquifer. Long dry periods may require deepening of well or an alternative water source.
The construction of unlined hand-dug wells is a labor-intensive and time-consuming activity. Costs can be limited if this labor is conducted by the users themselves. With paid labor, the total cost of a 10-20 m deep well may cost USD300-1000.
Unlined hand-dug wells are most often used at household- or shared household-level, but are applicable for small communities. Since little facility management is needed, managing can be easily done by a single person.
Large diameter wells can be made in most soil compositions which provide either clay (containment) or a permeable layer (quick recharge). Digging is best executed towards the end of the dry season when water table is lowest. Design needs to anticipate on low water levels during droughts. High contamination risk from (e.g. latrines).
Above the static water table, 3-4 m/day progress can be achieved. Digging becomes difficult below the water table. Dewatering may be necessary to reduce risk of collapsing at this depth. Regular monitoring is advised for contaminations in vicinity of well. Unstable soils or subsoils increase risk of collapsing.
Unlined hand-dug wells are in general highly affordable and locally acceptable. Especially organic (pathogenic) risk to public health from surface, vegetation, and animal excreta. Household-level water treatment is recommended. Cover on well reduces risk of children falling in.
No relevant remarks for Unlined hand-dug wells.