The slug test results for Hilly and Valley boreholes for the Bouwer & Rice (1976) and Hvorslev (1951), and Cooper
et al. (1967) methods are presented in
Figures 4–
6, respectively. The resultant hydraulic parameters for the two boreholes are presented in Tables 3 and 4. The hydraulic conductivities were estimated using the full open section length of the boreholes despite the evidence from the borehole dilution tests and geological mapping (to come later) of flow on preferential flow pathways. The hydraulic conductivities range between 7.1 × 10
−4 and 5.8 × 10
−3m/d for the Hilly borehole whereas that for the Valley borehole ranges between (3.4–4.9) × 10
−2m/d. The percentage difference between the highest values of the Bouwer & Rice (1976) and Hvorslev (1951), and Cooper
et al. (1967) methods are 10 and 156%, and 25 and 36% for the Hilly and Valley boreholes, respectively, which is reflective of the similarity and differences of the analytical methods and the non-uniqueness of the choice of curves for the Cooper
et al. (1967) method (See
Figure 6(a)). The interval transmissivities and storage coefficient estimated for Hilly and Valley boreholes are 3.4 × 10
−2 and 3.18 m
2/d, 10
−7 and 10
−5, respectively, which indicates that the Valley borehole is more conductive and has a two-order of magnitude more storage space than the Hilly borehole. This agrees with the faster pressure dissipation times (
t or
T37%) in the Valley borehole vis-à-vis that in the Hilly borehole
; and the nature of diffuse and preponderance of flow features identified in the Valley borehole. In addition, the slug test results agree well with the location of the boreholes, where the lower elevation area borehole (Valley) is expected to be more productive and transmissive than the recharge/higher elevation borehole (Hilly), due to flow convergence and concentration in the lower elevation area. developing flow features over time, thereby making the Valley borehole more transmissive.
Table 3Slug test results and hydraulic parameters for Hilly and Valley boreholes using the Bouwer & Rice (1976), and Hvorslev (1951) methods
| Borehole name
. | Analysis type
. | Le (m)
. | K (m/d)
. | t/T37% (s)
. |
|---|
| Hilly borehole | Bouwer and Rice | 56.5 | 5.20 × 10−3 | 30,000 |
| Hvorslev | 5.80 × 10−3 | 44,580 |
| Valley borehole | Bouwer and Rice | 41.5 | 4.88 × 10−2 | 900 |
| Hvorslev | 3.79 × 10−2 | 990 |
| Borehole name
. | Analysis type
. | Le (m)
. | K (m/d)
. | t/T37% (s)
. |
|---|
| Hilly borehole | Bouwer and Rice | 56.5 | 5.20 × 10−3 | 30,000 |
| Hvorslev | 5.80 × 10−3 | 44,580 |
| Valley borehole | Bouwer and Rice | 41.5 | 4.88 × 10−2 | 900 |
| Hvorslev | 3.79 × 10−2 | 990 |
Table 4Slug test results and hydraulic parameters for the boreholes using the Cooper et al. (1967) method
| Borehole name
. | β
. | α
. | Le (m)
. | t (mins)
. | T (m2/d)
. | K (m/d)
. | S
. |
|---|
| Hilly borehole | 1 | 1 × 10−7 | 56.5 | 190 | 0.04 | 7.07 × 10−4 | 1 × 10−7 |
| Valley borehole | 2 | 1 × 10−5 | 41.5 | 10 | 1.41 | 3.39 × 10−2 | 1 × 10−5 |
| Borehole name
. | β
. | α
. | Le (m)
. | t (mins)
. | T (m2/d)
. | K (m/d)
. | S
. |
|---|
| Hilly borehole | 1 | 1 × 10−7 | 56.5 | 190 | 0.04 | 7.07 × 10−4 | 1 × 10−7 |
| Valley borehole | 2 | 1 × 10−5 | 41.5 | 10 | 1.41 | 3.39 × 10−2 | 1 × 10−5 |
Figure 4
Slug tests results of the Hilly borehole using: (a) Bouwer and Rice method and (b) Hvorslev method.
Figure 4
Slug tests results of the Hilly borehole using: (a) Bouwer and Rice method and (b) Hvorslev method.
Figure 5
Slug tests results of the Valley borehole using: (a) Bouwer and Rice method and (b) Hvorslev method.
Figure 5
Slug tests results of the Valley borehole using: (a) Bouwer and Rice method and (b) Hvorslev method.
Figure 6
Field slug test curve fitting and parameter determination using the Cooper et al. (1967) method for: (a) Hilly borehole and (b) Valley borehole.
Figure 6
Field slug test curve fitting and parameter determination using the Cooper et al. (1967) method for: (a) Hilly borehole and (b) Valley borehole.
