r - part - usaid

This kind of calculation is often rcnsi.dered to be too
theoretical because the major portion of this cost is made up of
capital zepiaceaent, spares, and maintenance charges, for which
no cash is required at the tine. However, referring back to the
discussion in Section 4.1.1.5 above, not recognising this cast
waufd caase WRA to fall short on its annual program of vehicle
and equipment replacement and maintenance.
As shown in Table 2.4.0, from the recent experience of the
project, the following drilling success rates are assumed:-
Bay Region Central Range
Total Nunbex of Boreholes 30 30
Exploratory wells 32 40% 5 5 0%
Wells with ha~d pump 2 7% 1 10%
Sells with diesel puzp 15 53% 4 40%
Well testing is considered in the node1 to be a separate
operation from pump installatiox (Appendices 4.4.1, and 4.4,2.,
Table 4j, In the experience of the Groundwater Project,
hawever, these operations were often carriel out during one
visit by the pump crew. This practice arose because the project
was supplied with one size of diesel pump, and the decision to
install a diesel or hanr2 operated pump was made during
development. Eight days and ten days are assumed for testing
each borehale in the Bay Region and Central Range respectively,
of which two days and four days respectively are allowed for
travel.
Though not a siqnfficant part of the tt;atal cost of well
constriction, the cost of we31 logging proves difficult to
estimate. The prabfem is one of logistics, Though the actual
tine required to carry out the work is quite short, generally
less than one day, the =peration must be carried out immediately
upon completion of drilling, and befo~e installation of the
screen and czsing, Because this stage of the operation is not
precisely predictable, and bearing in mind the coat of idle t ime
for a drilling team, the logging vehicle inevitably spends some
time waiting on the drilling operation. Five and seven days
respectively for each borehsie in the Bay Region and Central
Rznge is allowed in the model (Appendices 4.4.1. and 4.4.2,
Table 5 ). Utilizing these figures for a program of drilling
such as that shown for 1986 at Appendices 4 .4.1 and 4,4,2, Table
21, the fallowing usage is inplied for the logging vehicle
(Appendices 4.4-1 end 4.4.2, Table 23).