WATER SUPPLY
Murray Biedler
July 09, 2012
WATER NEEDS
Drinking
Food Prep
Hygiene / Washing
Agric / Stock
CHARACTERISTICS
of
WATER SUPPLY




Quantity
Quality
Access and Sources
Treatment
Not static… constantly changing
WATER QUANTITY


Europe 150-litres/p/day average
Emergencies
•
•
•
•
20-litres/p/day minimum
5-litres/p/day: opening of emergency
Health centre: 1-2 litres/consultation
Hospital: 40-60 litres/patient/day (100 for
surgery)
• Therapeutic feeding centre: 30 litres / child /
day
• Cattle: 30 l/animal/day
• Small animals: 5 l/animal/day
WATER QUALITY

Bacteriological quality linked to:
• Faecal contamination indicative of
pathogens (e.g. cholera or typhoid)
(rapid assessment in field)

Chemical quality linked to:
• Geological surroundings, agricultural or
other industrial/commercial activities
(rapid assessment difficult lab required)
WATER QUALITY
Good Quality:
 Contains no pathogens
 Low concentration of toxic products
 Clear (low turbidity)


Is not too salty or mineralized
Colour, odour and taste acceptable
WATER ACCESS:
CHALLENGES
Time
Cost
Distance & Security
WATER ACESS: SOURCES



Surface water
• rivers, lakes, ponds
(access seasonal)
Ground water
• Difficult access but can
be better quality
Precipitation
• Seasonal: rain, snow,
fog capture
WATER ACCESS: SURFACE
On site pumps to
storage / tower
Gravity network,
pipes & taps
WATER ACCESS:
GROUNDWATER
Hand-dug wells:
hand pumps, buckets

Boreholes (shallow &
deep)
pumps: hand, motor,
solar, wind…

WATER ACCESS: SPRINGS
Springs: on site
pumps or gravity
into networks,
pipes & taps
WATER ACCESS:
PRECIPITATION
Rainwater collection
gravity to tanks
networks, pipes &
taps
WATER ACCESS: STORAGE



Storage provides
availability on regular
basis
Storage tanks provide:
• Treatment of large
volumes
• Pressure with gravity
Dams: surface and
subsurface; seasonal &
precipitation constraints
WATER ACCESS DISTRIBUTION



1 tap/200 persons for
displaced populations
Health facilities: taps for
staff, patients & visitors
Container distribution
WATER TREATMENT



Chlorination simplest &
most efficient way to kill
micro-organisms
Residual chlorine
necessary to attack
further contaminations
Chlorination becomes
inefficient if the water is
too dirty or turbid
SEDIMENTATION &
FILTRATION



Water stored until suspended particles settle
Water can be filtered with sand or other
designed materials
Coagulation-flocculation for heavy turbidity
using chemicals (e.g.ferric chloride or aluminium
sulphate)
DOMESTIC STORAGE
Container
lid or top (e.g:
jerry can) or a
narrow opening
(transport)
kept clean
regularly dosed for
residual chlorine
(storage)
MAIN ISSUES TO BE
CONSIDERED
NEEDS ANALYSIS
TECHNICAL
OPTIONS
ENSURING
QUALITY
ADAPTED
WATER
SUPPLY
AVAILABLE
QUANTITY
SANITATION AND
HYGIENE
POTENTIAL
SOURCES