| APPROPRIATE WELL DESIGN
Small Size Hand-dug
Wells for Households far from Large
Villages and Main Roads
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 .
23. For people living in small, remote villages and
hamlets, poorly or not connected with major roads and
towns, it is essential to secure a reliable safe water
supply upon which they can depend, with little outside
aid. The new well must therefore be as simple as
possible.
24. The well design has to meet appropriate sanitary
conditions and therefore its top section should be lined
with impermeable material to a depth of at least 3 m and
should have a concrete or masonery apron and a drain to
carry away the spilled water (see fig.
1).
This type of well should be lined, or partially lined,
according to prevailing geological conditions. Water
should be collected by buckets secured by rope. The well
top should be around 1 m diameter or less, and equipped
with hinched well cover.
25. Another appropriate water source for remote small
padas and vasties is a shallow drilled well equipped with
bucket pump (see
photo). The well depth, in most
cases is on the order of 60-70 ft; the bucket to withdraw
water consists in a 5 liters capacity cylinder bearing a
foot valve at its bottom. The cylinder is hanged to a
1/4" flexible steel rope which is lifted and lowered
manually by means of an iron drum . A platform completes
the installation of the bucket pump (see fig.
2). A detailed description of
the bucket pump is reported in another paper submitted
by the author to this Convention.
For the above conditions, the following three
types of water source 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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