| APPROPRIATE WELL DESIGN
Hand Dug Wells for
Households at Higher Density Located Close to Main Roads
and Towns
The well design will depend on a number of factors, as
already mentioned in paragraph 9. Among the various
possible well designs, the most appropriate are briefly
described .
26. For communities densely distributed, the following
points should be considered:
- The dangers of contamination and
epidemics are higher than in scarsely populated
areas therefore wells have to be technically well
constructed to prevent pollution.
- densely populated areas are generally
close or along the main roads and can easily be
reached for regular maintenance and repair of
pumps;
- in highly populated areas it is easy, in
many cases, to find someone with technical
knowledge for pump maintenance and repair.
For the above conditions, the following three
types of water sources upgrading could be considered:
- Upgrading of Unlined
Large-size Open Holes
27. Unprotected large size open holes are often
the main water
sources for small and medium sized villages.
Water in these holes
is extremely polluted and dirty. For their
effective upgrading it
is necessary to reduce their size , covering the
top with a cement
slab, and installing a hand-pump, fig.
3.
This will secure safe
water especially if the well is periodically
chlorinated.
- Upgrading Small
Sized Open Holes into Backfilled Wells
28. In many places, especially those inhabitated
by tribal
people, irregularly dug small diameter open
holes, yielding
permanent water, are often the main water sources
for small
hamlets. These small holes could be easily
enlarged, deepened and
upgraded to supply safe water by installing hand
pumps. The
characteristics of the backfilled wells are shown
in fig. 2.
The backfilled wells, however, can be considered
appropriate only
if villages are easily reachable for pump repair
also during the
rainy season, or if other permanent water sources
are available
nearby.
29. Water from backfilled wells, as well as from
those equipped
with bucket pumps, because of their low yield,
should be used
mainly for drinking and cooking, while water from
open hand-dug
wells, or other available water sources, should
be used for
washing, bathing, watering stocks and other
domestic needs. This
concept of having two water sources for the
mentiond uses, should
be part of the new safe water policy to secure
better health to
people.
- Improvement of Small
Size Rudimentarily Lined Wells and Large Size
Unlined Holes
30. Open wells lined by masonery wall without top
protection, can
be successfully upgraded by covering them with
re-inforced
concrete slab.
The well cover has a manhole to withdraw water
when the pump is
under repair. The upgrading of large size holes
into
properly constructed wells for households at high
density and
close to main roads is shown in Fig.
4.
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