HYDROGEOLOGICAL CHARACTERISTIC OF AQUIFERS

AND

BOREHOLE PERFORMANCE ASSESSMENT

FOR RURAL WATER SUPPLY IN SOUTHERN PART OF

STATE KADUNA, NW NIGERIA

6th Rural Water Supply Network Forum 2011 Uganda

Dr. M.O. Eduvie Rural Water Supply and Sanitation Centre,

National Water Resources Institute

Kaduna Nigeria

Dr. J.A. Otun Dept. of Water Resources Engineering,

Ahmadu Bello University Zaria

Nigeria

Introduction • The importance of groundwater as a water supply

source to the socioeconomic development of any

nation is tremendous

– GW is the only viable source of water in many remote

villages where development of surface water is not

economically viable.

• Some difficulties experienced in its exploration and

exploitation in the basement areas where aquifers

are both isolated and compartmentalized

• Exploration programme now requires the use of

multi-disciplinary approach involving, geological and

hydro-geological mapping, geophysical

investigations.

6th Rural Water Supply Network Forum 2011 Uganda

Study Approach

• Conceptually, locating productive boreholes in

areas with inadequate hydrogeological

information is usually difficult and very tasking.

• A multidisciplinary approach was used to study

and characterize the aquifer parameters and

evaluate the groundwater potentials of the

crystalline basement of the study area in Kaduna

State.

6th Rural Water Supply Network Forum 2011 Uganda

Multi-Disciplinary Approach • Preliminary hydrogeological assessment:

– Used to describe and understand the salient

hydrogeological features of its dominant rock types

• Hydrological review

– as it affects the groundwater availability,

– in addition to surface geophysical surveys (using the

electromagnetic (EM) and resistivity techniques), well

water level measurements, borehole drilling and pumping

tests and water quality analysis that were carried out.

• Spatial Mapping and Interpretations: Mapping of obtained superimposed data to produce several hydro-

geological maps that are best considered to be valuable for

interpretation and management of the entire ground water resources

of the study area.

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Assessment of Hydrogeological Characteristics:

• Geological and Hydrogeological Mapping:

Set of hydrogroundwater configuration maps

were constructed by the superimposition method

and the corresponding hydrogeological cross

section drawn.

• Geophysical survey: Electromagnetic (EM)

method used for some traversing, the resistivity

method using Wenner array was also employed.

– Vertical electrical soundings were conducted in

promising zones identified after profiling

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Geological and structural map of the study area

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Groundwater Configuration Map of the study area

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Hydrological cross section of NE-SW line

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Geophysical Investigations: Typical EM responses in the study

area

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Findings

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• Two geophysical survey techniques employed

proved effective in determining the regolith aquifers

in terms of thickness of water saturated zone with

subsurface layering ranging from 3-5 layers.

• Characterization of borehole parameters within the

study area :

– Borehole yields (7.2-302.4 m3/day),

– Aquifer transmissivity (0.359-101 m2/day) and

– Hydraulic conductivity (0.03 -10.9m/day)

• Obtained database helped in constructing hydro-

geological maps

Conclusions

6th Rural Water Supply Network Forum 2011 Uganda

• The study through its multi-disciplinary

approach showed the high groundwater

potentials of the basement complex area of

Southern parts of Kaduna State of Nigeria.

• It derives quantum of hydrogeological

information databases which were non-

available before the study:

– Preparation of hydrogeological maps

– Borehole logging database,

– Water quality analysis and database,

– Well reviews and pre-drilling geophysical investigations;

Conclusions

6th Rural Water Supply Network Forum 2011 Uganda

• With the quantum of hydrogeological

information databases derived from several

multi-disciplinary analysis carried out the

entire groundwater resources in the study

area is certainly poised and optimised for

effective rural water supply;

• Understanding these hydrogeological

characteristics of the weathered/fractured

aquifers in this study area is essential for

sound borehole design, construction and

management.

• ,