HASLER, WOWO
BSCE-V
Rural Water Supply
Rural Water
In rural and outback areas conventional methods of water sourcing, extraction,
and supply are not cost effective, especially so in the rural areas of developing
countries, which need simple, alternative methods to satisfy their domestic water
needs. Water supply to such rural communities can be sourced from rainwater,
groundwater or spring/surface water. Through simple rainwater harvesting
techniques, household as well as community needs for water in arid and semi-arid
regions, where no other water sources are available or feasible, can be met.
Groundwater is, by far, the most practicable choice for safe water supply. There is
a wide range of low-cost groundwater extraction techniques available. In areas
where groundwater is not available in adequate quantities, the next best available
option for water supply is from surface water sources. Often, surface water
sources are more contaminated than groundwater, which necessitates treatment
of water and hence increases the costs of water supply projects. There are simple
treatment methods available to provide minimal levels of treatment to produce
safe water free of microbial contamination. Depending on the quality of raw
water, a treatment method can be selected from a limited choice of low-cost
treatment methods to achieve better water quality. Distribution of water from a
central source to the community is also an important aspect of water supply. For
rural communities, distribution can be done through stand posts and yard tap
connections via a branched network of pipes.
Water is an indispensable natural resource for the survival and wellbeing of
human kind. It is also essential for production of food, energy that contributes to
the economic and industrial development of a society. Safe and reliable supply of
water is therefore essential for individual welfare and for community
development. The first and foremost consequence of lack of safe water for
community consumption is diseases. Infectious diseases, affected by the
availability or the lack of protected water supply systems, may take the following
forms
•Infections spread through water supplies (water-borne diseases such as typhoid,
cholera, gastroenteritis).
•Infections transmitted through living carriers found in water bodies (water-based
diseases such as schistosomiasis, which is through an aquatic snail that burrows
through skin).
•Infections spread by insects that depend on water (water-related diseases such
as malaria, yellow fever spread through mosquitoes).
•Infections due to the lack of sufficient water for personal hygiene (water washed
diseases such as scabies, trachoma).
World Health Organization (WHO) estimates that as much as 80% of all diseases in
the world are associated with water. Available evidences indicate that most of the
health benefits from safe water are attainable at service levels of 30–40 liters per
capita per day. Hence, the role of organized water supply in the prevention of
water-borne diseases and in the promotion of public health can be well
appreciated. It has been established that this role is best fulfilled when every
house in a given community is connected to the public water supply system. But
for most developing countries, this ideal is still unattainable due to financial and
other constraints.
Sources of water in rural areas
Traditionally, the people in rural areas have obtained water from unprotected
ponds or tanks, wells, cisterns and sometimes streams and rivers. These water
sources are frequented daily for collecting drinking and cooking water, washing
clothes, bathing, livestock washing, etc.
Basically, all sources of freshwater originate from rainfall, which is slightly acidic
due to dissolution of carbon dioxide in the atmosphere. In the form of surface
run-off, it will gather considerable amounts of organic and mineral matters, soil
particles, microorganisms, etc. When the surface run-off infiltrates into subsoil
it forms groundwater. As the groundwater level increases and rises above surface
level due to varying land formations, it oozes out as springs. Perennial springs are
the fountainheads of surface water bodies such as streams, rivers and lakes. The
source of water has a major effect on water system design and hence costs.
Water from different sources varies in quality and hence requires varying degrees
of treatment. The process of choosing the most suitable source for water supply
largely depends on the local conditions. A source of water supply can be identified
at any of the above stages of water cycle, provided it can supply in sufficient
quantities for most periods of the time in a year. Thus, water supply for rural
communities can be organized with use of rainwater, groundwater, and, spring
and surface water.
Rainwater based Rural Water Supply Systems
Rainwater can be considered as a source of water supply in regions where the
pattern of rainfall permits its harvesting. Rainwater harvesting is possible in
countries where rainfall is heavy, with long intervals with no rainfall. It can be a
suitable source in arid and semi-arid areas where people live in scattered
settlements and no other sources are available. Rainwater harvesting may serve
well for household as well as community level supplies. It can also be used in
conjunction with supply from other sources when their supplies are unpredictable
in nature. Rainwater harvesting at household level is done by storage of rainwater
through roof catchments and at community level by storage through ground
catchments.
Roof Catchment and Storage
Rainwater with reasonable qualities can be collected using rooftop areas that can
be stored to provide individual households in rural areas with adequate water
supplies. By directing the rainfall on the roof areas to flow through simple
collection gutter arrangements, water that would otherwise join surface run-off
can be gainfully utilized. Roofs made of tiles, slates, corrugated iron/tin or
asbestos sheets are more suitable. Thatched and lead sheet roofs are not suitable
because of health hazards. A typical roof catchment and storage arrangement is
shown
Roof catchment and storage
The roof guttering should slope evenly towards a downpipe to avoid sagging and
hence pooling of water that may become a breeding place for mosquitoes. It may
be helpful to arrange to divert the first flush of water from a roof collection, as it
will wash with it the accumulated dust and impurities such as bird droppings,
dead leaves, etc. The roof and guttering should be cleaned regularly. A wire mesh
placed over the top of the downpipe would prevent it from becoming clogged
with washed-off materials. The amount of rainwater that can be harvested will
depend on the area of the roof. The storage tank, however, has to be of sufficient
capacity to take care of the longest dry season in a normal year. To take care of
exceptionally dry years, another 50% surplus storage can be added. The minimum
basic drinking and domestic water requirement of a family of six persons is 40
liters per day. Thus, for an average dry season of 3 months, the water storage
required will be 3 × 30 × 40 × 1.5 = 5400 L.
