GWP4_PP_Water Distributionx - RedR

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25 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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WASH Cluster


Groundwater Pumping

GWP

GWP4

1

Groundwater Pumping

Session 4

Water Distribution









WASH Cluster


Groundwater Pumping

GWP

GWP4

2








2

2

2

Protection of Water Source


A water point obviously
attracts a great deal of
human contact. This is a
potential source of
contamination and should
be protected against:


The well should be in an
elevated place, so that
during the rainy season the
water will run away from it,
rather than into it


It should be at least 30
meters away from a latrine


It should be at least 30
meters away from a cattle
kraal

WASH Cluster


Groundwater Pumping

GWP

GWP4

3








3

3

3

3

Protection of Water Source

The construction of a platform
(or slab) at the wellhead is an
important contribution to the
general hygiene in a
community.



The slab should be made from good quality concrete of


All surfaces must slope towards the drainage channel


The slab should be well reinforced with steel wire, to prevent cracking


Where possible, the drain can lead to a vegetable garden.


WASH Cluster


Groundwater Pumping

GWP

GWP4

4








4

4

4

4

4

Curing of Concrete work
(Platform and Drainage channel)

A curing time of at least one
week is needed.

During the curing period, the
platform has to be watered
regularly, so that the concrete
never gets dry.

Direct sunlight must be avoided
by covering the slab with wet
hessian cloths, foliage, wet soil
or sand.

Cover the well platform and
drainage channel with thorn bush,
for protection from being destroyed
by people or passing animals.


WASH Cluster


Groundwater Pumping

GWP

GWP4

5








5

5

5

5

5

Fencing the Water Source

In some cases, it may be
necessary to have a gateway
to keep out smaller animals
such as pigs and goats.

The fencing should be made of
suitable local materials like
wood or stones.

Problems of replacement and
repair can be avoided
altogether, by using a living
hedge as a fence.

Whatever type of fencing is
used, it is important that
access by the well users is
guaranteed.


WASH Cluster


Groundwater Pumping

GWP

GWP4

6








6

6

6

6

6

Soak pit

Construct a soak pit if no natural drain is available.

Excavate a hole and fill it with stones, broken bricks, gravel and sand.

To prevent sand from being washed away, fix a mud pot (with holes in
the bottom) at the end of the drainage channel, so that the spill water
can drain slowly

WASH Cluster


Groundwater Pumping

GWP

GWP4

7








7

7

7

7

7

Disinfecting the Well

As soon as the curing time is over and the
platform is ready for installation of a
handpump, the well needs to be disinfected
with chlorine.


It is recommended to use between 150
to 200 grams of bleaching powder per
m³ stored in the well casing.


Check amount of water collected in the
well casing and calculate how many
grams of bleaching powder are
required.


Mix the required amount of bleaching
powder thoroughly in 15 litres of water
(in a bucket) and pour it into the well.

WASH Cluster


Groundwater Pumping

GWP

GWP4

8

Water distribution


When water is pumped to a higher
elevation the pumping effort is the total
head plus the friction head loss in the
pipeline. The friction head loss for a
given flow rate can be calculated for any
chosen pipe diameter. Smaller pipes
create higher losses than bigger pipes
because the water speed is greater. The
pump has to be chosen that is able to
produce the required flow and pressure.


Water demands varies across the year

P
eak hour demand = average
hourly demand x hourly peak factor (k2).








WASH Cluster


Groundwater Pumping

GWP

GWP4

9

Water Reservoirs


A reservoir balances supply rate from the
water source with the fluctuating water
demand in the distribution area. The
storage volume should be large enough to
accommodate the cumulative difference
between water supply and demand.


A storage volume of 20 to 40% of the
peak day water demand should generally
be adequate


The reservoir should be situated as close
as possible to the distribution area. It
should be situated at a higher elevation
than the distribution area.









Reservoirs are of reinforced concrete; masonry; steel; plastic

WASH Cluster


Groundwater Pumping

GWP

GWP4

10

Distribution System


Two types of distribution systems are used; the
branched or the looped systems.


For small
-
capacity a branched system can be
used. It is laid out like a tree, in which the
“trunk” is the Main Pipeline and the “branches”
are the Service Pipes.


Looped system are based on a grid of
interconnected delivery pipes. The Main
Pipeline is feeding Branch Pipelines, which are
connected in a loop, so that all Service Pipes
are fed from two sides. This system is more
complicated to design and more costly, but
provides stable water pressure, and small
sections of the system can be isolated for
repairs.








WASH Cluster


Groundwater Pumping

GWP

GWP4

11

Public Stand post


Public stand posts are the best option
for water distribution at minimum cost
to a large number of people who
cannot afford the much higher costs of
house or yard connections.


Each stand post should be situated at
a point within the community area to
limit the walking distance to 200 m


The discharge is about 14 to 18
litres/minute at each outlet. A single
tap stand should preferably be used
by not more than 40 to 70 people
(approx. 10 families); a multiple tap
stand may provide a reasonable
service for up to 250 to 300 persons