AVAILABILITY OF BOREHOLE SYSTEMS FOR POTABLE WATER SUPPLY
AVAILABILITY OF BOREHOLE SYSTEMS FOR POTABLE WATER SUPPLY
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Date
1997
Authors
MBAMALI, Ikemefuna
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Abstract
The work articulates borehole systems definition and project
criteria, as systems evaluation principles. These serve as
background knowledge for the assessment of availability of
handpump-equipped boreholes in the Crystalline Groundwater Province
of Northern Nigeria.
The study which is mainly based on project files and
performance records, draws samples of a hundred boreholes from each
of four states (Kaduna, Kano, Kwara and Niger States) within the
area of interest. Also assessed are such related measures of
systems effectiveness as: reliability, maintainability, failure
patterns and frequencies, times to first failure, up-times and
down-times of the boreholes.
The study shows that there are no significant differences in
the respective values of these parameters, in the four states.
Availability as a measure of the up-times of the boreholes over the
initial five-year period of their operation is found satisfactory.
However, as a measure of the probability for adequate performance
over the designed life of the boreholes, with no down-times in
excess of one week; availability is found problematic as from the
fourth year of operation of the boreholes. The handpump sub-system
shows a much higher failure frequency - 88% approx.of the system
failure - than the well. This in turn is accounted for mainly by
the cylinder assembly, riser pipe and head assembly components;
with 41%, 22%, 12% approx. of the system failure respectively.
Suggestions made for improving the availability include:
improving the inherent reliablity of the handpump, closer
monitoring of the borehole systems in operation to ensure timely
failure identification and reporting, keeping adequate stock of
spares and swift mobilisation of resources for repair work.
Description
Being a dissertation submitted to the Postgraduate School
of Ahmadu Bello University, Zaria, in partial fulfilment of the
requirement for the award of the Doctor of Philosophy (Ph.D) degree
in Building, Faculty of Environmental Design, Ahmadu Bello
University, Zaria, Nigeria
Keywords
AVAILABILITY,, BOREHOLE,, POTABLE,, WATER SUPPLY