Aquifers derived from the crystalline basement rocks for parts of Sanga Local Government area of Kaduna State, Nigeria consist of clay, silt, sand, gravel and laterite materials which may be in various proportions. Using Cooper-Jacobs non-equilibrium graphical method, the hydraulic properties were estimated from pumping test data of 18 boreholes. Conductivity varies from 1.02 × 10 ﹣2 m/s to 4.07 × 10 ﹣2 m/s and transmissivity varies from 1.14 × 10 ﹣1 m 2/s to 4.40 × 10 ﹣1 m 2/s. The values of specific capacity range between 1.03 × 10 ﹣1 m 2/s/m and 9.00 × 10 ﹣2 m 2/s/m, and these values indicate that the aquifers in the area have low to moderate ground water potentials. The low yield range of between 0.45 l/s and 1.00 l/s recorded in the area shows the heterogeneous and anisotropy nature of the basement aquifer system in terms of groundwater discharge. On the average, the boreholes assessed have potentials to sustain local to regional supply provided the best drilling method and materials are used and well completion properly done.
Sanga local government is located at the extreme southern part of Kaduna state. It shears boundary with Nasarawa State Southward and covers a total land area of about 1402 Km2 with a population of 149,333 [
The area investigated is located between Latitudes 9˚15'N to 9˚30'N and Longitude 8˚8'E to 8˚40'E at the southern part of Kaduna State, Nigeria. The area falls within the Guinea Savannah climatic belt of West Africa which is characterized by two distinct seasons, the wet and dry season. The wet period lasts for a period of 7 months commencing in March/April and terminates in October. The Eastern portion of the area receives more rainfalls due to its close proximity to the Jos Plateau region [
The area consists of rocks that range in age from Pre-Cambrian to Lower Palaeozoic and Quaternary period. Four groups of rocks can be distinguished for the Basement Complex Terrain in the area [
consists of the metasediments in the area and is represented by the quartzite. The third group is the intrusive rock consisting mainly of granites. The fourth group of rock is the basalt which is Quaternary in age. The ground water in the area contains in the soft overburden, fractured bedrock, and alluvium aquifers [
Pumping test data for the 18 boreholes tested were obtained from the rural water supply unit of Kaduna state ministry of water resources. The boreholes were drilled under the MDGs (millennium development gold) program for the year 2009 by Carling Earth Resources Nigerian Limited Kaduna Nigeria were used for this study [
Pumping test data from 18 boreholes were used. The aquifer was tested for periods of between 60 and 180 minutes depending on the time equilibrium was reached in the individual well. The is’ non-equilibrium graphical method is given bellow
where s = drawdown,
Q = constant well discharge,
S/NO | Community | Borehole depth (m) | SWL (m) | Screen length (m) | Final drawdown (m) |
---|---|---|---|---|---|
1 | Agamati Market | 30 | 7.00 | 9.00 | 16.20 |
2 | Fadan Karshi | 43 | 7.00 | 12.00 | 9.94 |
3 | Kufai Aboro | 43 | 13.48 | 12.00 | 6.89 |
4 | Ankara | 40 | 11.74 | 9.00 | 13.42 |
5 | Maitozo Distric House | 29 | 6.20 | 9.00 | 20.70 |
6 | Kwagiri Village | 32 | 6.20 | 9.00 | 16.70 |
7 | LGEA Landa | 27 | 5.1 | 9.00 | 10.70 |
8 | Dorowa | 30 | 14.43 | 9.00 | 3.80 |
9 | Kwassu Ung. Dutse | 33 | 13.74 | 12.00 | 7.03 |
10 | FadanAyu | 28 | 4.00 | 9.00 | 12.50 |
11 | Dangam | 22 | 6.50 | 12.00 | 9.90 |
12 | LGEA Ancha | 24 | 4.20 | 9.00 | 6.80 |
13 | LGEA Aboro | 27 | 7.50 | 12.00 | 15.30 |
14 | PHC Kutal | 25 | 5.60 | 9.00 | 8.20 |
15 | LGEA Amantu | 23 | 4.00 | 9.00 | 12.50 |
16 | Aboro Village | 31 | 7.30 | 9.00 | 11.00 |
17 | LGEA SabonGida | 30 | 6.90 | 9.00 | 5.10 |
18 | Wasa Village | 31 | 9.20 | 9.00 | 13.30 |
u = well function,
T = Transmissivity,
r = radius of well.
This was used for the estimation of transmissivity (T) and Storage (S) but assuming a small radius for the well, and a fairly long pumping time, Equation (1) above was simplified [
where ∆s = drawdown over one long cycle.
In determining the slope ∆s early times were excluded because for early time approximation is not valid due to casing/wellbore storage, true aquifer response to pumping is masked until storage is exhausted. Only the medium and late times were considered, these represent a transition period during which matrix blocks feed their water to an increasing rate to fractures resulting in partly stabilizing drawdown and pumped water coming from storage in the fractures and matrix block respectively [
The Hydraulic Conductivity K is computed from the relation:
where B = aquifer thickness or length of screen used,
T = Transmissivity.
While Specific capacity was computed from the equation
where Q = borehole yield or discharge,
s = total drawdown recorded in pumped well.
Transmissivity recorded in the area ranges between 1.14 × 10−1 and 4.40 × 10−1 with an average of 2.18 × 10−1 while the hydraulic conductivity ranges between 1.02 × 10−2 and 4.07 × 10−2 with an average of 2.18 × 10−2. Hydraulic conductivity obtained falls within the range given in
Reduction as well as break in discharge experience during pumping, is an indication of the heterogenic and anisotropic nature of the basement aquifer in the study area. The low to average Transmissivity value of 2.18 × 10−2 m2/s of the aquifer is attributed to the decrease in aquifer thickness and saturation. High average Drawdown recorded values
S/N | Community | Discharge Q (l/s) | Transmissivity T (m2/s) | Hydraulic conductivity K (m/s) | Specific capacity m2/s/m | Drawdown per log cycle ∆s (m) |
---|---|---|---|---|---|---|
1 | Agamati Market | 0.50 | 1.31 × 10−1 | 1.10 × 10−2 | 3.10 × 10−2 | 0.70 |
2 | Fadan Karshi | 0.86 | 1.43 × 10 | 1.20 × 10−1 | 9.00 × 10−2 | 0.11 |
3 | Kufai Aboro | 0.84 | 4.40 × 10−1 | 3.66 × 10−2 | 4.00 × 10−2 | 0.20 |
4 | Ankara | 0.68 | 2.07 × 10−2 | 2.30 × 10−2 | 5.10 × 10−2 | 0.60 |
5 | Maitozo District Head House | 0.60 | 3.04 × 10−1 | 3.05 × 10−2 | 3.00 × 10−2 | 0.40 |
6 | Kwagiri Village | 1.00 | 2.30 × 10−1 | 2.54 × 10−2 | 6.00 × 10−2 | 0.80 |
7 | LGEA Landa | 0.75 | 2.30 × 10−1 | 2.54 × 10−2 | 7.01 × 10−2 | 0.60 |
8 | Dorowa | 0.70 | 3.00 × 10−1 | 3.20 × 10−2 | 1.84 × 10−1 | 0.45 |
9 | Kwassu Ung. Dutse | 0.50 | 2.61 × 10−1 | 2.20 × 10−2 | 7.11 × 10−2 | 0.35 |
10 | Fadan Ayu | 0.64 | 1.60 × 10−1 | 1.74 × 10−2 | 5.12 × 10−2 | 0.70 |
11 | Dangam | 0.70 | 1.83 × 10−1 | 1.53 × 10−2 | 7.07 × 10−2 | 0.70 |
12 | LGEA Ancha | 0.70 | 3.22 × 10−1 | 3.60 × 10−2 | 1.03 × 10−1 | 0.40 |
13 | LGEA Aboro | 0.60 | 1.22 × 10−1 | 1.02 × 10−2 | 4.00 × 10−2 | 0.70 |
14 | PHC Kutal | 0.45 | 2.10 × 10−1 | 2.30 × 10−2 | 5.50 × 10−2 | 0.40 |
15 | LGEA Amantu | 0.50 | 1.14 × 10−1 | 1.30 × 10−2 | 4.00 × 10−2 | 0.80 |
16 | Aboro Village | 0.70 | 2.60 × 10−1 | 2.85 × 10−2 | 4.02 × 10−1 | 0.50 |
17 | LGEA SabonGida | 0.80 | 4.00 × 10−1 | 4.07 × 10−2 | 2.00 × 10−1 | 0.40 |
18 | Wasa Village | 0.50 | 1.14 × 10−1 | 1.30 × 10−2 | 4.00 × 10−2 | 0.80 |
Aquifer property | Transmissivity T (m2/s) | Hydraulic conductivity k (/m/s) |
---|---|---|
Minimum | 1.14 × 10−1 | 1.02 × 10−2 |
Maximum | 4.40 × 10−1 | 4.07 × 10−2 |
Mean | 2.18 × 10−1 | 2.18 × 10−2 |
obtained shows the aquifer to be poor in terms of both recharge and discharge of groundwater; this is also an indication of the inefficiency of the aquifer as a transmitting medium. It is evidently clear also that the low yields range of between 0.45 to 1.00 l/s recorded, high level of drawdown recorded and poor aquifer properties obtained for the area, indicated that the aquifers in this area are predominantly made of fine clayey or Silty materials which are derived from the in situ chemical decomposition of the basement rock which are generally characterised with low permeability and poor water yield. The value range of conductivity obtained in this study fall within the range of 10−3 to 10−1 as given by [
The area is characterised by low to moderate groundwater resources, since this is the readily available portable source of water available, there is a need for this resource to be properly harness by carrying out an in-depth investigation on the groundwater resources reserve in the area. Similarly it is strongly recommended that a longer duration of pumping test period of about 24 hours should be adopted in the future so that a better assessment of the aquifer productivity and water potentials can be fully properly determined. The use of modern technology and scientific methods such as groundwater modelling will assist in giving the clear picture of the subsurface and understanding of the groundwater resources of the area. It will also give the chance to water managers to properly plan for the present and future water demand for the fast growing population in the area before the provision of pipe borne water is realised in the area.
They authors wish to thanks the staffs management of Kaduna state ministry of Water resources for making available the pumping test results and other relevant inform that has assisted in the facilitating this study.
Hassan, H., Waru, S.M., Bukar, G.A. and Abdullahi, K.M. (2016) Groundwater Potentials Estimation of a Basement Terrain Using Pumping Test Data for Parts of Sanga Local Government Area, Kaduna State, Northwestern Nigeria. Open Journal of Modern Hydrology, 6, 222- 229. http://dx.doi.org/10.4236/ojmh.2016.64018