Aquifer Hydraulic Conductivity Calculation
This solution explains how to calculate the hydraulic conductivity ($K$) of a confined aquifer using the given transmissivity ($T$) and thickness ($b$).
Key Formula and Parameters
The relationship between transmissivity ($T$), hydraulic conductivity ($K$), and aquifer thickness ($b$) for a confined aquifer is:
$ T = K \times b $
Given values:
- Aquifer Thickness ($b$) = $10$ m
- Transmissivity ($T$) = $0.75$ m2/day
Calculating Hydraulic Conductivity
To find the hydraulic conductivity ($K$), rearrange the formula:
$ K = \frac{T}{b} $
Now, substitute the given values into the formula:
$ K = \frac{0.75 \text{ m}^2/\text{day}}{10 \text{ m}} $
Performing the calculation:
$ K = 0.075 \text{ m/day} $
Therefore, the hydraulic conductivity of the confined sandy aquifer is $0.075$ m/day.
Important Questions from Aquifer Properties
- An aquifer has a surface area of 100 km$^2$. With no recharge, assume that pumping out 2 $\times$ 10$^7$ m$^3$ of ground water resulted in a drop of the water table by 6 m. If the aquifer has a specific retention of 15 %, then the porosity of the aquifer is _____ % (rounded off to one decimal place).
- A well penetrates an unconfined aquifer. The water level (i.e., head) in the well prior to pumping is 25 m. After a long period of pumping at a constant rate of 0.05 m$^3$/s, the drawdowns at distances of 50 m and 150 m from the well are observed to be 3 m and 1.2 m, respectively.
The hydraulic conductivity of the unconfined aquifer is ______ $\times 10^{-4}$ m/s (rounded off to two decimal places).
Consider $\pi$ = 3.14. - A confined aquifer with a uniform saturated thickness of 10 m has hydraulic conductivity of $10^{-2}$ cm/s. Considering a steady flow, the transmissivity of the aquifer in $m^2/day$ is _______ (rounded off to one decimal place).
- A stratified confined aquifer consists of three parallel homogeneous and isotropic horizontal layers with thickness of 10 m, 5 m and 5 m. The layers have the same width. The hydraulic conductivities of the strata are 15 m/day, 20 m/day and 30 m/day, respectively. The water flow follows Darcy's law and is parallel to the strata. Considering the same hydraulic gradient for all the layers, the effective hydraulic conductivity of the aquifer is ________ m/day. [in integer]
If $d$ is the depth of an aquifer through which water is flowing, then the relationship between permeability $K$ and transmissibility (also known as transmissivity) $T$ is given by ________.
