Technical brief

Hand-dug wells
Part of a series ofWaterAid technology
briefs.
Available online atwww.wateraid.org/technologies
January 2013

Introduction
The traditional method of obtaining groundwater in rural areas of thedeveloping world, and still the most common, is by means of hand‑dug wells.
However, because they are dug by hand, their use is restricted to suitabletypes of ground such as clays, sands, gravels and mixed soils where only smallboulders are encountered. Some communities use the skill and knowledge of
local well‑diggers, but often the excavation is carried out, under supervision, by
the villagers themselves.
The volume of the water in the well below the standing water table acts as areservoir which can meet demands on it during the day and should replenish
itself during periods when there is no abstraction.

Fig 1: A hand‑dug well

Technical brief

Hand-dug wells

Dimensions of hand-dug wells
Hand‑dug wells can range in depth
from about five metres deep, to deep
wells over 20 metres deep. Wells
with depths of over 30 metres aresometimes constructed to exploit
a known aquifer. It is impractical toexcavate a well which is less than ametre in diameter; an excavation of
about 1.5 metres in diameter provides
adequate working space for thediggers and will allow a final internal
diameter of about 1.2 metres after thewell has been lined.

Fig 2: A safe well‑digging operation

Water
discharging

Air lineto pump

Air compressor unit
placed so that fumes
cannot reach the well

Safety equipment
and first aid kit

Brake
post

Dewatering pump

Bosuns chair
Air control valve2

Technical brief

Hand-dug wells

Digging with the sides of the excavation supported
There are several methods ofsupporting the sides of the excavation
while digging proceeds:
Pre-cast concrete rings
The safest method is to excavate
within pre‑cast concrete rings which
later become the permanent lining
to the sides of the well. The first ringhas a cutting edge, and additionalrings are placed on it as excavation
proceeds. As material is excavatedwithin the ring, it sinks progressively
under its own weight and that of therings on top of it. This method should

always be used in unstable ground.
When construction has finished,
the joints between the rings which
are above the water table should besealed with cement mortar.
In situ lining
In suitable ground, excavation may
proceed for a short distance without
support to the sides; these are thensupported by means of concrete
poured in situ from the top, between
the sides of the excavation andtemporary formwork, which becomesthe permanent lining to the well. This
process is repeated until the watertable is reached.
Supported excavation(the ‘Chicago’ method)
In suitably stable ground, excavation
may proceed within the protection ofvertical close-fitting timber boards,
supported by horizontal steel rings(the Chicago method). The timbers
are hammered down as excavation
proceeds and additional timbers
are added progressively at groundlevel. The steel rings must be hinged,
or in two parts bolted together, sothat lower ones can be added as theexcavation progresses. The verticalspacing between the rings will dependon the instability of the ground. The
well is lined with bricks or concrete
blocks, from the water table upwards,
within the timbers as they arewithdrawn.

WaterAid/Jim Holmes

A wide-diameter well being
constructed in Uganda using
the Chicago method of safe wellconstruction. The photo illustrates theuse of a temporary support system forsafe digging in open holes. Steel rings,
wedges and timber boards ensure thesafety of workers at any depth.
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Hand-dug wells

Digging with the sides of the excavation unsupported
In stable ground, wells are often
excavated down to water level without
a lining, and are lined with in situ
concrete, or with pre‑cast concreterings, from this level upwards.
Wells safely dug during the dry seasonmay become unstable when the waterlevel rises in the wet season andtherefore must be lined before thisoccurs to prevent a collapse.

In firm and stable ground, wells may
be safely excavated without supportand may give satisfactory service,although it is strongly recommended
that a permanent supporting lining beinstalled. This will support the sides ofthe excavation, preventing them fromcollapse and preventing pollution bysurface water. Suitable lining materials
have been shown in the following
sketches and include concrete, pre‑cast concrete, masonry and brickwork.

Fig3: Different ways of lining a well
Method 1

Method 2

Method 3

Method 4

Sinking pre‑castconcrete rings.

Reinforced concreteor ferrocement cast in
situ above water line,
concrete rings sunk
below the water line.

Masonry lining of burnt
bricks above water line,
caisson made of blocks
with cutting ring below
water line.

Galvanised iron rings
bolted together as
temporary measure for
emergencies.

1m

Concrete
apron

Bricks orblocks

50mm
thick

Chicken wire
reinforcement

Backfillwithgravel

Concreterings

Ferrocement
cast in situ

Galvanised
iron rustsquickly
in acidicwaters

0.9m

Water
line
Sunk
caissons

Cuttingring

Each circle of galvanised
iron is composed ofthree curved sections
bolted together

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Hand-dug wells

Excavation below the water table
Regardless of which method has beenused to excavate the well to the watertable, excavation below this levelshould never be attempted until thesides of the excavation have received
the support of their permanent lining,from water table to ground level.

Fig 4: Example of excavation below
water table using concrete caissonrings

Excavation below the water tableshould be carried out within pre‑castconcrete caisson rings of a smaller
diameter than the rest of the well. To
facilitate the ingress of water, theselower rings are often constructed withporous, or no-fines, concrete andtheir joints are left unpointed. See thediagram (right):

ClayCast in situ
or pre‑castconcretecaisson rings

Porousconcretecaisson rings
Water table
Sand
aquifer
Cutting ringFig 5: Hand-dug well fitted withhandpump

ConcretesurroundClay – toseal thewall1mConcrete
layer

AquiferGravel orsand to act
as filter

1.25m

Completion
After construction of the well shaft
has been completed, the bottom
is plugged with gravel. This helps
to prevent silty material from clay
soils, or fines from sandy materials,
being drawn into the well. Anyannular space between the pre‑castcaisson well rings and the side of the
excavation should also be filled withgravel; such filling behind the rings
which are below the water helps toincrease water storage and to preventthe passage of fine silts and sands
into the well.
The space behind the top three
metres, or so, of the well rings should
be backfilled to ground level withpuddled clay, or concrete, and the wellrings should project about one metre.
An apron and a drain should then beconstructed. This apron should be
wide enough for people to stand on.
It should be made of concrete thatis between 75 and 100mm thick,5Technical brief

Hand-dug wells
preferably reinforced by steel rods ormesh. This apron provides a sanitary
seal to prevent polluted water seeping
into the well. It should have a smoothsurface sloping down to the drainand a rim to prevent water goingover the edge. The drain should be acement‑lined channel, at least four
metres long, that takes spilled water
to a soakage pit, an animal‑wateringtrough or a vegetable garden.

Abstraction
Water is abstracted by means ofeither a bucket and windlass above

an access hole, or a handpump,depending upon the yield ofwater available and the ability ofthe benefiting community to pay
for ongoing maintenance for thehandpump, spare parts, etc. A hand‑
dug well fitted with a handpump canserve the needs of about 300 people.

References
Watt S B and Wood W E (2007) Handdug wells and their construction.
IT Publications
WaterAid (2000) WaterAid’s healthand safety policy

Advantages of hand-dug wells✓ Cheap materials can be used
✓ Can be constructed by local artisans so communities can build themselves✓ Generally good yields

Disadvantages of hand-dug wells✗ Can be time‑consuming to construct✗ Risk of collapse if not supported properly✗ Depth of well is limited✗ Unless capped or protected, hand‑dug wells can be open to contamination

An example of ahandpump operated
hand-dug well withan apron and drainsurrounding the wellhead in Adi-awnawaza village in theHintalo-Wajarat
region of Ethiopia

WaterAid/Marco Betti

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Technical brief

Case study

Hand-dug wells

Example of the hand-dug well method

WaterAid/Jon Spaull

The well being pumped out, Woriziehi, Tamale, Northern Region, Ghana
Hand‑dug wells have been constructed for thousands of years but in the past this water supply
often consisted of unlined holes (prone to collapse), that were unprotected from contamination,
leading to health risks.
In order to avoid these problems it is advisable to use the method outlined below:
Materials requiredfor construction:• Shovel andpickaxe• Concrete rings,
the first one witha cutting edge
and smaller
diameter ones tocontinue past thewater table depth• Cement mortar• Cement andreinforced steelrods or mesh to
create apron anddrain• Gravel

Construction methodology:• Excavate to depth of first pre-cast concrete ring and to diameter ofapproximately 1.5metres• Add additional concrete rings as excavation deepens – de-watering
will need to take place to keep excavating after water table depth isreached• Use smaller diameter rings to continue excavating from water table todesired depth• Plug bottom of well with gravel after construction• Fill any annular space between concrete rings and outer excavation
with gravel to create a gravel pack (preventing silts and sands passinginto well)• When construction is finished, fill the joints between the concreterings above the water table with a cement mortar• Top three metres of rings should be grouted with concrete to create asanitary seal
• Create apron or install concrete slab and drain to prevent ponding ofwater at well7

Water source options: See how hand‑dug wells compare to other water source options

Technical brief

Hand-dug wells

Bacteriologicalwater quality

Situation in which technology ismost applicable

Water source

Capital cost

Running cost

Yield

Springprotection

Low or medium if
piped to community

Low

High

Good if springcatchment isadequately protected

Reliable spring flow required
throughout the year

Sand dams

Low – local labourand materials used

Low

Medium/high –depending on method
used to abstract water.
Water can be abstracted
from the sand andgravel upstream of thesand dam via a well or
tubewellGood if area upstreamof dam is protected

Can be constructed acrossseasonal river beds onimpermeable bedrock

Sub surface
dams

Low – local labourand materials used

Low

Medium/high –Good if area upstream
depending on methodof dam is protected
used to abstract water.
Water can be abstracted
from the sand, gravel orsoil upstream of the subsurface dam via a well or
tubewellCan be constructed in sediments
across seasonal river beds onimpermeable bedrock

Infiltration
galleries

Low – a basicinfiltration gallery
can be constructedusing local labourand materials

Low

Medium/high –depending on method
used to abstract waterGood if filtration
medium is wellmaintained

Should be constructed next tolake or river

Rainwater
harvesting

Low – low costLowmaterials can beused to build storage
tanks and catchment
surfaces

Medium – dependent on
size of collection surface
and frequency of rainfall

Good if collection
In areas where there are one or
surfaces are kept clean two wet seasons per year
and storage containers
are well maintained

Hand-dug wellcapped with arope pump

Low

MediumGood if rope andpump mechanisms aresealed and protectedfrom dust. Area around
well must be protected

Where the water table is not
lower than six metres – althoughcertain rope pumps can lift
water from depths of up to 40metres

Medium – spare parts
required for pumpHand-dug wellcapped with ahand pump

MediumMedium – spare parts
required for pump

MediumGood if area around
well is protected

Where the water table is not
lower than six metres

Tube wellor borehole
capped with ahand pump

Medium – welldrilling equipment
needed. Boreholemust be lined

Medium – hand pumps
need spare parts

MediumGood if area aroundborehole/tubewell is
protected

Where a deep aquifer must beaccessed

Gravity supply

High – pipelines and Low
storage/flow balancetanks required

High

Good if protectedspring used as source

Stream or spring at higher
elevation – communities served
via tap stands close to the home

Borehole
capped withelectrical/
diesel/solar
pumpHigh – pump andstorage expensive

High – fuel or powerHigh
required to run pump.
Fragile solar cells need tobe replaced if damaged

Good if source isprotected

In a small town with a large
enough population to pay forrunning costs

Directriver/lakeabstraction
with treatment

High – intake must
be designed andconstructedHigh – treatment andpumping often required.
Power required for
operation

Good following
treatment

Where large urban populationmust be served

ReverseosmosisHigh – sophisticated High – power required for Highplant andoperation. Replacement
membranes required membranes required

Good

Where large urban populationmust be servedHouseholdfilters

High – certain filters
can be expensive topurchase/produce

Filters can be fragile.
Replacement filters canbe expensive or difficult
to source

Low

Good as long as
regular maintainanceis assured

In situations where inorganic
contaminants are present
in groundwater sources orprotected sources are notavailable

SODIS (solardisinfection)

Low – although
clear bottles can bedifficult to source inremote areas

Low

Low

GoodIn areas where there is adequate
sunlight – water needs to be
filtered to remove particulatematter that may harbour
pathogens before SODIS can be
carried out effectively. SODIS
is not appropriate for use withturbid water= most preferable= preferable

High= least preferable

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Technical brief

Hand-dug wells

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