Abstract:
Field and laboratory studies were carried out to evaluate the groundwater
potentials of Enugu State. The studies involved evaluation of groundwater data
of the area to determine the quantity and quality of groundwater resources
potential of the area. A census of existing boreholes was conducted and all
available information on each borehole were collected and collated. These
included geologic classifications, geophysical data, hydro-geological data and
issues on ground-water exploitation. There were a total number of 117 boreholes
studied and these were spread all over the state across different geologic
formations. The geology of the area was studied to determine the aquifers,
aquicludes and aquitards. The hydrologic parameters such as hydraulic
conductivity, K, transmissivity, porosity, yields and storage capacity were
determined by standard methods, analysed and used to evaluate the
groundwater potentials of the area. Three major geologic formations namely the
Awgu Formation, Agbani Formation and Ajali Formation were evaluated for their
groundwater potentials. Various relationships between geologic parameters and
borehole characteristics were determined. These included borehole yields, drill
depths, specific capacities, static drawdowns and dynamic drawdowns. The Awgu
sandstone presented the least groundwater potentials with yields ranging from
1
1.07 l/s to 17.69 l/s with an average of about 6.318 l/s. Agbani sandstone
showed slightly higher potentials with yields ranging from 10.88 l/s to 11.6 l/s
with average yield of about 11.66 l/s while the yields from Ajali sandstone which
incidentally is predominant in the area ranged from 5.94 l/s to 97.22 l/s with an
average yield of about 22.46 l/s. Groundwater quality parameters were evaluated
for the geologic formations in comparison with water quality standards. A total
number of twenty (20) water quality parameters were analysed for the various
water boreholes. Generally, these parameters were within the limit of acceptable
international and national water quality standards. The study also showed that
some of the causes of failure of groundwater exploitation include not carrying
out pre-drilling investigations; use of incompetent personnel with lack of
technical know how; use of improper equipment and machineries for drilling, lack
of well development and installation of appurtenances; use of inappropriate
appurtenances/accessories as well as improper drilling methods and techniques.
In addition to the above is the lack of institutional framework to coordinate and
manage groundwater resources and facilities. The study established that Enugu
State has adequate groundwater reservoir potentials both in quality and quantity.
