r - part - usaid
r - part - usaid
r - part - usaid
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farms <strong>part</strong> of the broad overhezd c ~st of WDA administration.<br />
The ma&el assumes three visits to the site by the<br />
hydrogealogfst and assistant (Appendices 4.4.9 znd 4.4.2, Table<br />
The purpose of the first visit is site selection, the<br />
second visit occurs during cirilLizg, and the third visit is fur<br />
aquifer testirg. Scme time is allowed at the office for<br />
analysis and reportisg. The difference in cost between the two<br />
versions represents the difference in cine allowed for travel to<br />
the site. The total times estimated for the hydrageological<br />
work in the Bay Segion and the Central Range are 15 and 24 days<br />
respectively.<br />
4-1-3. Drilling<br />
As ran be seen from Figures 2 .4.; and 2.4.2, the actual<br />
drilling phase. af weif construction is the most significant.<br />
These figvres exclude WDA overhead costs kt include direct<br />
costs, capital recovery, anc? aaintenance charges. Drilling<br />
accounts for alms? 50% of the total cast of a well equipped<br />
with a diesel puzp in the Bay Region, and for over 63% in tke<br />
Central Range. From Fiqures 2.4.3 and 2.4,4 the percentages<br />
rise to 808 and 66% respectively for wells equipped with a<br />
bandpump.<br />
The average depth of a borehole in the Bay Region program<br />
is taken as 12031 [Appendix 4,4.1, Table 2). For the Central<br />
Eange program, 150m is assuaed (Appendix 4.4.2, Table 2). In<br />
both cases a 5n surface casing is assumed, an average of 16n of<br />
steel screen is used, acd the remainder of the hole is lined<br />
with solid steel casing. The nodel does net automatically<br />
relate the depth to the time taken to drill the well. Drilling<br />
time is dependent upon a number of other variables.<br />
Based on projecx experience, a drilling crew in the Bay<br />
Zegiun has been employed on each production borehole for an<br />
average of 35 days, and on each exploratory borehole for 23 days<br />
(Table 2.015). Tn the Central Range, the corresponding figures<br />
are 57 days and 38 days (Table 2.4.6). On average, an<br />
exploratory wall takes two tkirds the time of a production well.<br />
he model bases the cost for IzSuux, and, more signficantly, for<br />
running coscs, capital replacement, and spares and maintenance<br />
for all equipment and vehicles, on this nu~,ker of days. This<br />
rule is only varied fox calcula%kng the fuel costa of the drill<br />
rig,