THE PAN-AFRICAN UNIVERSITY INSTITUTE FOR WATER AND ENERGY
SCIENCES (INCLUDING CLIMATE CHANGE)
WATER ENGINEERING
HYDROGEOLOGY
COLLINS ACHEAMPONG
Theis and Jacob-Cooper pump test fit
Assignment 5
From the graph,
t = 0.48 min, s = 1.45
w (u)= 10, 1/u = 10, u =0.1
𝑠=
𝑄
𝑤(𝑢)
4𝜋𝑇
𝑟 2𝑆
𝑢=
4𝑇𝑡
𝑇=
𝑇=
𝑄
𝑤(𝑢)
4𝜋𝑠
788
× 10
4𝜋 × 1.45
𝑇 = 432.5 𝑚3 ⁄𝑑𝑎𝑦
𝑆=
𝑆=
4𝑇𝑡𝑢
𝑟2
4 × 432.5 × 0.48 × 0.1
302 × 60 × 24
𝑆 = 6.41 × 10−5
Using Aqtesolv software to solve for T and S by the Theis method
Manual Graphic, Cooper-Jacob straight fit method
Jacob straight line method
0.1
1
Time (min)
10
100
0
0.2
∆s
Drawdown (m)
0.4
0.6
0.8
1
y = 0.1274ln(x) + 0.2753
R² = 0.9899
1.2
2.3𝑄
𝑇 = 4𝜋∆𝑠 𝑆 =
2.25𝑇𝑡0
𝑟2
From the graph, ∆𝑠 = 0.58 − 0.28 = 0.3
𝑡0 = 0.11 𝑚𝑖𝑛
𝑇=
2.3 × 788
4𝜋 × 0.3
480.75 𝑚2 ⁄𝑑𝑎𝑦
𝑆=
2.25 × 480.75 × 0.11
302 × 60 × 24
= 9.18 × 10−5
1000
Using Aqtesolv software to solve for T and S by the Cooper-Jacob straight method
Table of Summary of Results
Theis Method
Parameters
Manual fit
T (𝑚3 ⁄𝑑𝑎𝑦
S
432.5
6.41 × 10−5
Cooper-Jacob
Aqtesolv
498.2
9.112 × 10−5
Some interpretations of results
T=b if we assume a b=8m using results from Theis.
K=432.5/8 = 54.06 m/d
K = 0.63 × 10−5 𝑚/𝑠
Manual fit
480.75
9.18 × 10−5
Aqtesolv
498.2
9.112 × 10−5
𝑇=
2.3 × 788
4𝜋 × 0.3
480.75 𝑚2 ⁄𝑑𝑎𝑦
T=b if we assume a b=8m using results from Jacob-Cooper
K=480.75/8 = 60.09 m/d
K = 0.69 × 10−5 𝑚/𝑠
Hence, the soil transmittivity is high and very good with high permeability
Also;
According to literature, for a confined aquifer, storativity results only from rock and fluid
compressibility and is typically very small (~10−4–10−5). Hence the since are storativity
values are within (~10−4–10−5), the aquifer might be a confined aquifer