Director,
T.E.(Terry)
Manning,
Schoener 50,
1771 ED
Wieringerwerf,
The Netherlands.
Tel:
0031-227-604128
Homepage:
http://www.flowman.nl
E-mail:
(nameatendofline)@xs4all.nl : bakensverzet
and
"Money is not
the key that opens the gates of the market but the bolt that bars them"
Gesell, Silvio The
Natural Economic Order
Revised English
edition, Peter Owen,
“Poverty is created scarcity”
Wahu Kaara, point 8 of the Global Call to Action Against Poverty, 58th
annual NGO Conference, United Nations,
This project does not cover all the possibilities offered by efficient
rain-water harvesting. Instead, it assumes small-scale rainwater harvesting
systems for agricultural purposes will be developed as a natural extension of
economic activity in the area.
Rain-water is harvested both for irrigation and for drinking water. Some
form of purification system is needed when it is used for drinking water as the
water may come into contact with dirty surfaces and may need to be stored for
quite long periods. Purification needs systematic technology application and
careful management. The effects can be disastrous if these things are
overlooked. That is why clean water from closed wells and boreholes has been
preferred as a source of drinking water to harvested rain-water in this
project.
The solar powered drinking water systems foreseen in this model project
offer a limited capacity suitable for human consumption, small animals and
small scale drip irrigation applied to high value cash crops. The project does
not include water for irrigation and general agriculture for which the use of
solar energy, taking into account the cost of PV panels and/or wind generators
into account, is still relatively uneconomic.
Rain-water harvesting offers the possibility of providing a water supply
suitable for small-scale agriculture and emergencies. The use of gypsum
composite water tanks and reservoirs made under the (LETS) systems means that
users do not actually need to have any "money" to start and gradually
expand their own rain-water harvesting systems.
The tanks can be gravity fed off roofs and/or slopes and/or road
surfaces. This water would also be used for personal hygiene such as showers,
and for the washing of clothes.
This project is limited to household water harvesting systems as a
supplementary non-potable water supply for personal uses.
Surfaces such roofs, roads, squares need to be gently sloped so that
water can run along gutters or other channelling material to one or more water
collection points. The channelling materials used should be locally made gypsum
composite materials to avoid financial leakage from the project area. In any
case PVC must not be used. The collection surface(s) should be kept as clean as
possible. Contamination of the surface by animals and waste products should
where possible be avoided. Green or "living" roofs may also be used
for rainwater harvesting but may reduce, through absorption, the amount of
water collected. The number of water collection points will depend on the
surface being drained and the maximum intensity of the rainfall. Purely
indicatively one collection point should serve about 40m2 or 300 square.feet..
The harvested water is intended for general household use and not for drinking.
Should it be required for drinking purposes it must be boiled or treated with a
Moringa sand filter.
Chlorination and other types of water treatment should be avoided except where
the water in the rainwater tank is the only source of water available and it is
known to be, or there is a reasonable risk that it be bacterially infected.
Even then treatment should only be carried out by a specialist.
The harvested water should however be filtered to keep organic
materials, solids and particles in suspension out. This can be done is two
phases:
a) At the collection point, with a fine metal grate together, eventually, with
a suitable sponge-like material at the top of the down-water pipe.
b) Above the water tank, where the water can pass through a gypsum composite or
other container (but not PVC!) filled with (locally available) shingle, sand,
and charcoal.
The size of the filters will depend from case to case according to the
maximum amount of flow reasonably foreseeable.
Their size will depend on the maximum amount of flow reasonable
foreseeable, but will typically have an internal diameter from 3" to
6". Their length will depend on where the water tank is situated. They
should be as short as possible. Where they are exposed to the sun's rays, the
pipes must be resistant to them. Where possible the pipes should be made from
locally available materials and supplied within the local LETS money systems.
Do NOT use PVC material.
Where possible, the water tanks should be sealed and placed just under
the roof, from where they can be gravity fed through pipes to outlet points in
or around the house. Recipients can also be placed on a stand between roof
level and floor level, so that gravity feeding is still possible. Where neither
of these is feasible, ground level recipients can be used. This usually
involves the use of lids, ladles, buckets and similar which may not be hygienic
and the risk of infection and access by animals and insects is increased.
Ground level tanks also occupy extra space.
The water tanks will
normally be spherical in shape and made locally under the LETS systems from
gypsum composite materials. Where they are esthetical in appearance and design,
their position is irrelevant.
The first systems
will be made in the gypsum composite factories and installed towards the end of the second year
of project execution. This work will continue during the following 4-5 years
until all of the (8.000) extended family houses in the project area have been
equipped.
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