PLANNING WATER SUPPLY AND SANITATION PROJECTS IN DEVELOPING NATIONS 1005
the financial (minimizing initial investment cost as well as
maintenance cost) and technical (minimizing operational
failures) resources; (3) training paraprofessional rural water
technicians (using available labor where possible instead of
expensive imported equipment); (4) promoting complemen-
tary activities to help people to obtain the most benefits from
the systems (so that users will receive long-term benefits of
these basic services); and (5) selection of the most appropri-
ate water source and the most appropriate energy source for
conveying water to its users.
The different sources of small community water supply
systems in developing countries can be categorized as fol-
lows: (1) groundwater, (2) rain water, (3) springwater, and
(4) surface water. Depending on the sources of water supply,
many techniques have been found effective and applicable
to the water and sanitation programs in the developing coun-
tries. Some of these techniques are presented below.
Groundwater In areas where groundwater is read-
ily available at moderate depth, constructing a number of
wells fitted with hand pumps is by far the cheapest means
of providing a good water supply.^14 Although, community
water systems piped under pressure to households and public
standposts may be an ultimate goal, many areas will realisti-
cally have to seek hand pumps as an interim if not an ulti-
mate measure. The trouble with most hand operated water
pumps used in developing countries is that they are not hardy
enough and require frequent maintenance. Pump parts are
usually expensive to buy and are difficult to make locally
to fit the pump. Development work started at the Consumer
Research Laboratory (CRL) in England has led to the snappy
plastic pump: a simpler, cheaper and hardier device that has
many beneficial features. A complete description of such
hand pumps is given by Sattaur.^15 Additional information on
other types of hand pump manufactured in developing coun-
tries may be found in Ref. 15. Hofkes provides some other
techniques and methods of groundwater withdrawal used by
small water supply systems in developing countries.^11
Rainwater In developing countries rainwater is some-
times used to supplement the other water supply sources. In
some tropical islands rainwater is the only source of domestic
water supply. Rainwater harvesting requires adequate provi-
sion for the interception, collection and storage of the water.
Generally, cisterns are built to collect the runoff from the
roofs. Water quality preservation is very important and some
basic measures should be followed to exclude bird drop-
pings, insects and dirt from the stored water. Also, storage
in cool conditions, exclusion of light, and regular cleaning
is essential. Simple disinfection devices may be very useful.
Rainwater catchments are relatively simple to construct
and maintain. It is expected that these systems will be widely
used in the future. In Kenya, concrete jars used as storage
tanks are said to be the most popular appropriate technology.
Their popularity is growing among the villagers in Thailand
where the construction and maintenance of these units is
undertaken by technicians of the Sanitation Division of the
Department of Health. The technician directs the voluntary
labor of villagers in constructing concrete storage tanks rein-
forced with bamboo. The Villagers then repay the costs ofthe tanks in 12 monthly installments. The owners of these
tanks, having contributed so much of their time and money
into their construction are usually very keen to operate and
maintain it properly.^16 Design details and economics of
many cisterns, storage tanks, and other rainwater harvesting
systems may be found in Refs. 17 – 21
Spring and Surface Water There are many situations in
the developing world where water is available from a nearby
stream or spring. Various devices have been constructed to
utilize the energy available in flowing streams to pump the
water to the point of use.
The more successful devices, that will represent substan-
tial savings in pumping water are the hydraulic ram pumps
(hydram) and low-head turbine pumps. One converts pres-
sure energy to mechanical work and the other converts kinetic
energy to mechanical work. These two practical devices
have been described and compared in detail by Schiller.^22 He
observed that the hydram is easier to operate and maintain,
but installation of the turbine pump is easier and simpler.
Before the Water Decade program started the water qual-
ity control was given least importance in developing coun-
tries. Perhaps, the major reason was inappropriate operation
and maintenance of the equipment. The primary goal of any
water project started in the Drinking Water Decade was to
provide a facility and system that can be operated, maintained
and managed at local levels giving self sufficiency with
proper personnel and financial needs.^23 Local capabilities
for operation and maintenance must be developed through
training local maintenance personnel, establishing a locally
managed maintenance fund, selecting an easily maintained
technology, and requiring capital contributions from the
community to increase local sense of ownership and respon-
sibility for the systems.^24 Finally, a successful drinking water
program requires extensive local participation (materials and
labor) and minimize dependence on overseas materials and
equipment for construction and operation of facilities.^25Human Waste DisposalRapid growth of the urban populations (mainly because of
migration from rural areas) has led to severe problems in
providing human waste disposal systems. Only 32 percent
of the population in the developing countries is directly con-
nected to sewer systems. Therefore, the collection and dis-
posal of human wastes constitute a serious environmental
and health problem.^26 Several alternatives are available; each
has its own limitations and constraints. Certainly there is
no single option appropriate to all situations. The range of
options described below is sufficient to cover the vast major-
ity of the situations within the low income communities of
the developing countries.
One of the fundamental principles of community sanita-
tion is to remove all putrescible matter, particularly human
wastes. A satisfactory excreta disposal method must satisfy
the following requirements:^261) Should not be accessible to flies or animals
2) Should not cause odors or unsightly conditionsC016_008_r03.indd 1005C016_008_r03.indd 1005 11/18/2005 11:01:57 AM11/18/2005 11:01:57 AM