1. Marco Bruni, seecon international gmbh
Wells
Marco Bruni, seecon international gmbh

2. Copy it, adapt it, use it – but acknowledge the source!
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Copy it, adapt it, use it – but acknowledge the source!
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3. Contents
Introduction
How Can Wells Optimise my Local Water System?
Prospecting for Groundwater Sources
Different Types of Wells and their Characteristics
Basic Design and Construction Principles
Operation and Maintenance
Applicability
Advantages and Disadvantages
References

4. Variability of the Groundwater Table
1. Introduction
Variability of the Groundwater Table
Infiltration of water into an aquifer during the wet season
Infiltration of water into an aquifer during the dry season
Source: SMET & WIJK (2002)

5. Groundwater Withdrawal from Wells by Means of Buckets or Pumps
1. Introduction
Groundwater Withdrawal from Wells by Means of Buckets or Pumps
Pumps
Source: [Accessed: ]
Source: IWMI (n.y.); NE (n.y.); WATER CHARITY (n.y.); BAUMANN (2011)
Rope & Bucket

6. 2. How Can Wells Optimise my Local Water System?
Health Aspects
A properly constructed well can improve a community’s water supply substantially.
High quality drinking water
No or just minor purification required
Many low-cost and low-tech digging and drilling options available
Source: BAUMANN (2011)

7. Where Should I Look for Groundwater?
3. Prospecting for Groundwater Sources
Where Should I Look for Groundwater?
Villagers and members of the neighbouring communities can be a good source of information on the presence of shallow groundwater.
Also, certain types of vegetation (e.g. banana plants, bulrushes, sugar can, date palms) can indicate presence of groundwater (COLLINS 2000).
Often, existing wells in close proximity indicate the presence of groundwater.
If technical equipment is available, test borings can give detailed information on the groundwater level.
Source: [Accessed: ]

8. Dug Wells Drilled Wells
4. Different Types of Wells and their Performance
Two Main Types of Wells
Dug Wells
Drilled Wells
Diameter: +/- 1.2m
Length: 3 – 20m
Diameter: +/- 50mm
Length: 10 – 50m (200m)

9. 5. Basic Design and Construction Principles
Location
Wells should not be constructed close to potential sources of contamination, e.g. pit latrines, livestock farming, fuel/pesticide/ fertiliser storage, etc.
Well should be located in close proximity to the actual point of water use
Source: BUCHANAN et al. (2010)

10. Well Head Well Shaft Intake
5. Basic Design and Construction Principles
Dug Well: Elements
Well Head
Well Shaft
Intake
Source: SMET & WIJK (2002)

11. 5. Basic Design and Construction Principles
Dug Well: Excavation
Excavation is done manually with pick and shovel
Lining is most often necessary to protect the well from collapsing and preventing subsequent contamination of the well
Materials for lining: prefabricated concrete rings, stones, bricks, masonry, etc.
Source: : [Accessed: ]

12. Drilled Well: Drilling
5. Basic Design and Construction Principles
Drilled Well: Drilling
Basic hand-drilling techniques
b) High-tech machine-drilling
Source: [Accessed: ]
Source: [Accessed: ]

13. Drilled Well: Drilling – Many Different Techniques
5. Basic Design and Construction Principles
Drilled Well: Drilling – Many Different Techniques
Basic Hand-drilling techniques
b) Machine-drilling
Sludging
Augering
Percussion
Jetting
Machine-drilling
Source: ELSON & SHAW (1995)
Source: WURZEL (2000)

14. Drilled Well: Completion
5. Basic Design and Construction Principles
Drilled Well: Completion
Completion of a well involve construction of a:
Well casing (prevents the well from collapse and seepage of contaminants).
Well screen (holds back sediments while allowing water to infiltrate the well)
Gravel pack (prevents the well screen from becoming clogged)
Sanitary seal & head works (prevents surficial contamination)
Source: WATERAID (2008)

15. 5. Basic Design and Construction Principles
Well Protection
Wells and aquifers are susceptible to contamination. Contaminants can either enter from the opening or from the sides of the excavation.
Water source protection involves:
Interdiction of all activities that can potentially cause contamination close to the well (e.g. pit latrines, livestock farming, fuel/pesticide/ fertiliser storage, etc)
Wellhead protection involves:
Drainage
Surficial seal: an apron
Impermeable lining (dug wells) or
casing (drilled wells)
Securing functioning of the pump
Source: NABUUR (n.y.)

16. 6. Operation and Maintenance
Dug Well
Structural maintenance includes:
Checking the apron for cracks,
Securing the inspection cover, Improving the yield by deepening or removing infiltrated sand particles, and the
Maintenance of the lifting device.
Equally, securing hygienic operation is essential. This involves:
Protection and cleaning of the area (e.g. fencing and covering),
Checking water quality and disinfecting if necessary,
Monitoring the effects of withdrawal on environment and surrounding areas, and
Educating water users in proper operation of the well.

17. 6. Operation and Maintenance
Drilled Well
Drilled wells are easy to operate and basically not in need for maintenance.
However, as a drilled well always include a manual or mechanised pump, maintenance of the lifting is critical!
Source: [Accessed: ]

18. Drilled Well Drilled Well
7. Applicability
Drilled Well Drilled Well
Can serve as a water supply for a rural community, depending on the performance
Low-tech solution  particularly for rural communities
Can serve as water supply for single households, for small rural communities as for more urban areas, depending on the size of the well (depth & diameter).
Manual drilling is applicable in alluvial soils up to 40 metres.
A pump must be available and frequently maintained

19. 8. Advantages and Disadvantages
Dug Well
Advantages:
High degree of involvement of the local community during the whole process
Under supervision, no skilled workers are required
Simple equipment sufficient for both construction and maintenance
Low cost for construction and O&M
Involvement of private sector possible (local well diggers)
Yield can be increased after construction  
Reservoir included (large diameter)
Disadvantages:
Long construction phase
Dangerous excavation
Motorised pump (power source) often required to lower the water table during construction
Application restricted to regions with rather soft geological formation and relatively high groundwater levels
Alteration of groundwater level can adversely affect the surrounding environment
High susceptibility for contamination
People (i.e. children) can fall in if the well is uncovered

20. 8. Advantages and Disadvantages
Drilled Well
Advantages:
Quicker and cheaper to sink than hand-dug wells
Less susceptible to contamination
No dewatering during sinking required
Less lining material required
Safer in construction and use
The well itself needs barely maintenance
Many simple drilling techniques available suiting many geological conditions
Disadvantages:
Skilled staff and experts required for drilling
Pump required, which needs appropriate operation and maintenance
Lower yield than hand-dug wells (smaller diameter)
Overexploitation may lead to adverse effects on the environment
Arsenic pollution may occur
More technical equipment and skills necessary for construction
No integrated storage capacity / recharge during periods of low abstraction

21. 9. References
BAUMANN, E. (2011): Low-cost Hand Pumps. St. Gallen: Rural Water Supply Network (RWSN). URL: [Accessed: ].
BUCHANAN, B.; DE LA CRUZ, N; MACPHERSON, J.; WILLIAMSON, K. (2010): Water Wells that Last for Generations. Edmonton: Alberta Agriculture and Rural Development. URL: [Accessed: ].
ELSON, B.; SHAW, R. (1995): Simple Drilling Methods. Leicestershire: Water, Engineering and Development Centre (WEDC), Loughborough University. URL: [Accessed: ].
IWMI (n.y.): Diesel pump in operation. Colombo: International Water Management Institute (IWMI). URL: solutions.iwmi.org/motorized-pumps.aspx [Accessed: ].
NABUUR (n.y.): Protected dug well in Uganda. Amersfoort: Nabuur. URL: improvem [Accessed: ].
NE (n.y.): Solar Water Pump. Lahore: National Engineers (NE). URL: [Accessed: ].
SMET, J. (Editor); WIJK, C. van (Editor) (2002): Small Community Water Supplies: Technology, People and Partnership: Groundwater Withdrawal - Chapter 10. The Hague: International Water and Sanitation Centre (IRC). URL: [Accessed: ].
WATERAID (2008): Technology Notes. London: Wateraid. URL: [Accessed: ]
WATER CHARITY (n.y.): Deep-well hand piston pump including apron and drain in Wallalan, Upper Badibu District, Gambia. Crestline: Water Charity. URL: [Accessed: ].
WURZEL, P. (2001): Drilling Boreholes for Handpumps. St. Gallen: Swiss Centre for Development Cooperation in Technology and Management (SKAT). URL: /skatpublication /file [Accessed: ].

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