Groundwater abstraction using handpump-equipped wells
From WaterWiki
Extraction of groundwater using handpump-equipped wells is an technology for augmentation of fresh water
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Technical description
Handpumps tap groundwater from shallow or medium depth aquifers and from deep aquifers if the at rest water level is high enough. Handpumps are water conveyance systems used to bring groundwater to the surface.
In normal circumstances, handpumps are installed in wide diameter wells, which can be constructed by hand to depths of up to about 15 m, or drilled by rigs to much greater depths. The type of well most widely used is the hand-dug well, which is one of the cheapest means for providing a small supply of water in rural areas.
Costs
While hand dug wells are quite inexpensive, boreholes drilled by rigs are fairly expensive in terms of initial capital costs. Dug shallow wells and augured tube wells have a per capita construction cost of $6 to $20, with an operation and maintenance cost of $0.02 to $0.14 per capita per year. Machine-drilled boreholes, equipped with a hand pump and serving a population of about 200 to 300 people, will have an estimated per capita construction cost of $19 to $23, and an operation and maintenance cost of $0.26 to $0.52 per capita per year. (Prices are based on costs in Africa)
Advantages
Well water is relatively safe without treatment. Hand dug wells are inexpensive and can be constructed using local skills and materials; community participation is easy to organize. Further, the operation of handpumps requires no external power and few skills, and the pumps may be maintained by local technicians. The use of spare parts is small.
Disadvantages
The capacity of a well is limited, and service supply levels are lower than in piped schemes supplied from conventional sources. Hand dug wells are reliable only in areas where good quality groundwater is available at shallow depth. The hygienic quality of the wells, especially shallow wells, is not always satisfactory as a result of surface water intrusions leaking through the slab and superstructure, and around the pump casing.
Further Readings, References, Links
UNEP's comprehensive Sourcebook of Alternative Technologies for Freshwater Augmentation and UNICEF's Handbook on Water offer an in-depth assessment of small scale technologies for water supply, augmentation, waste water treatment for all regions.
Groundwater Resources Sustainability Indicators
Source(s)
Sourcebook of Alternative Technologies for Freshwater Augmentation in Africa
