Presentation on theme: "Marco Bruni, seecon international gmbh"— Presentation transcript:
1Marco Bruni, seecon international gmbh WellsMarco Bruni, seecon international gmbh
2Copy it, adapt it, use it – but acknowledge the source! Copyright & DisclaimerCopy it, adapt it, use it – but acknowledge the source!CopyrightIncluded in the SSWM Toolbox are materials from various organisations and sources. Those materials are open source. Following the open-source concept for capacity building and non-profit use, copying and adapting is allowed provided proper acknowledgement of the source is made (see below). The publication of these materials in the SSWM Toolbox does not alter any existing copyrights. Material published in the SSWM Toolbox for the first time follows the same open-source concept, with all rights remaining with the original authors or producing organisations.To view an official copy of the the Creative Commons Attribution Works 3.0 Unported License we build upon, visit This agreement officially states that:You are free to:Share - to copy, distribute and transmit this document Remix - to adapt this document. We would appreciate receiving a copy of any changes that you have made to improve this document.Under the following conditions:Attribution: You must always give the original authors or publishing agencies credit for the document or picture you are using.DisclaimerThe contents of the SSWM Toolbox reflect the opinions of the respective authors and not necessarily the official opinion of the funding or supporting partner organisations.Depending on the initial situations and respective local circumstances, there is no guarantee that single measures described in the toolbox will make the local water and sanitation system more sustainable. The main aim of the SSWM Toolbox is to be a reference tool to provide ideas for improving the local water and sanitation situation in a sustainable manner. Results depend largely on the respective situation and the implementation and combination of the measures described. An in-depth analysis of respective advantages and disadvantages and the suitability of the measure is necessary in every single case. We do not assume any responsibility for and make no warranty with respect to the results that may be obtained from the use of the information provided.
3ContentsIntroductionHow Can Wells Optimise my Local Water System?Prospecting for Groundwater SourcesDifferent Types of Wells and their CharacteristicsBasic Design and Construction PrinciplesOperation and MaintenanceApplicabilityAdvantages and DisadvantagesReferences
4Variability of the Groundwater Table 1. IntroductionVariability of the Groundwater TableInfiltration of water into an aquifer during the wet seasonInfiltration of water into an aquifer during the dry seasonSource: SMET & WIJK (2002)
5Groundwater Withdrawal from Wells by Means of Buckets or Pumps 1. IntroductionGroundwater Withdrawal from Wells by Means of Buckets or PumpsPumpsSource: [Accessed: ]Source: IWMI (n.y.); NE (n.y.); WATER CHARITY (n.y.); BAUMANN (2011)Rope & Bucket
62. How Can Wells Optimise my Local Water System? Health AspectsA properly constructed well can improve a community’s water supply substantially.High quality drinking waterNo or just minor purification requiredMany low-cost and low-tech digging and drilling options availableSource: BAUMANN (2011)
7Where Should I Look for Groundwater? 3. Prospecting for Groundwater SourcesWhere 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: ]
8Dug Wells Drilled Wells 4. Different Types of Wells and their PerformanceTwo Main Types of WellsDug WellsDrilled WellsDiameter: +/- 1.2mLength: 3 – 20mDiameter: +/- 50mmLength: 10 – 50m (200m)
95. Basic Design and Construction Principles LocationWells 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 useSource: BUCHANAN et al. (2010)
10Well Head Well Shaft Intake 5. Basic Design and Construction PrinciplesDug Well: ElementsWell HeadWell ShaftIntakeSource: SMET & WIJK (2002)
115. Basic Design and Construction Principles Dug Well: ExcavationExcavation is done manually with pick and shovelLining is most often necessary to protect the well from collapsing and preventing subsequent contamination of the wellMaterials for lining: prefabricated concrete rings, stones, bricks, masonry, etc.Source: : [Accessed: ]
12Drilled Well: Drilling 5. Basic Design and Construction PrinciplesDrilled Well: DrillingBasic hand-drilling techniquesb) High-tech machine-drillingSource: [Accessed: ]Source: [Accessed: ]
13Drilled Well: Drilling – Many Different Techniques 5. Basic Design and Construction PrinciplesDrilled Well: Drilling – Many Different TechniquesBasic Hand-drilling techniquesb) Machine-drillingSludgingAugeringPercussionJettingMachine-drillingSource: ELSON & SHAW (1995)Source: WURZEL (2000)
14Drilled Well: Completion 5. Basic Design and Construction PrinciplesDrilled Well: CompletionCompletion 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)
155. Basic Design and Construction Principles Well ProtectionWells 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:DrainageSurficial seal: an apronImpermeable lining (dug wells) orcasing (drilled wells)Securing functioning of the pumpSource: NABUUR (n.y.)
166. Operation and Maintenance Dug WellStructural maintenance includes:Checking the apron for cracks,Securing the inspection cover, Improving the yield by deepening or removing infiltrated sand particles, and theMaintenance 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, andEducating water users in proper operation of the well.
176. Operation and Maintenance Drilled WellDrilled 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: ]
18Drilled Well Drilled Well 7. ApplicabilityDrilled Well Drilled WellCan serve as a water supply for a rural community, depending on the performanceLow-tech solution particularly for rural communitiesCan 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
198. Advantages and Disadvantages Dug WellAdvantages:High degree of involvement of the local community during the whole processUnder supervision, no skilled workers are requiredSimple equipment sufficient for both construction and maintenanceLow cost for construction and O&MInvolvement of private sector possible (local well diggers)Yield can be increased after construction Reservoir included (large diameter)Disadvantages:Long construction phaseDangerous excavationMotorised pump (power source) often required to lower the water table during constructionApplication restricted to regions with rather soft geological formation and relatively high groundwater levelsAlteration of groundwater level can adversely affect the surrounding environmentHigh susceptibility for contaminationPeople (i.e. children) can fall in if the well is uncovered
208. Advantages and Disadvantages Drilled WellAdvantages:Quicker and cheaper to sink than hand-dug wellsLess susceptible to contaminationNo dewatering during sinking requiredLess lining material requiredSafer in construction and useThe well itself needs barely maintenanceMany simple drilling techniques available suiting many geological conditionsDisadvantages:Skilled staff and experts required for drillingPump required, which needs appropriate operation and maintenanceLower yield than hand-dug wells (smaller diameter)Overexploitation may lead to adverse effects on the environmentArsenic pollution may occurMore technical equipment and skills necessary for constructionNo integrated storage capacity / recharge during periods of low abstraction
219. ReferencesBAUMANN, 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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