A sand layer of 15 m is overlain by 7.5 m clay layer which is further ...
Concept:
Using Darcy’s law
q = kiA
k → permeability of soil
i → hydraulic gradient
A → Area of Soil Sample
Calculation:
hydraulic gradient (i) is =
h = head causing flow in the clay layer
Take C1 as datum
Total head at C1 = Datum head + Pressure head
= 0 + (7.5 + 10 + 7.5) = 25 m
Total head at C2 = Datum head + Pressure head
= 7.5 + 10
= 17.5 m
(T.H)C1 > (T.H)C2
Flow is occurring from C1 to C2 (upward)
Head causing the flow = (T.H)c1 − (T.H)c2
= 25 – 17.5
HL = 7.5m
L = 7.5m
A = 1 m2
k = 1.5 × 10–5 cm/sec
k = 1.5 × 10–7 m/sec
q = 1.5 × 10–7 × 1 × 1
q = 1.5 × 10–7 × 60 × 60 × 24 × 1 × 1
q = 12. 96 × 10–3 m3/day
q = 12.96 litres/day
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A sand layer of 15 m is overlain by 7.5 m clay layer which is further ...
To calculate the quantity of flow into the pond from the clay layer, we need to determine the flow rate through the clay layer.
The flow rate through a porous medium can be calculated using Darcy's law:
Q = K * A * h / L
Where:
Q = flow rate (in cubic meters per second)
K = hydraulic conductivity of the medium (in meters per second)
A = cross-sectional area of flow (in square meters)
h = hydraulic head difference (in meters)
L = length of flow path (in meters)
In this case, the flow path is the thickness of the clay layer (7.5 m), and the hydraulic head difference is the rise in elevation observed in the standpipe (7.5 m).
First, we need to convert the flow rate from cubic meters per second to liters per day. There are 86,400 seconds in a day, and 1 cubic meter is equal to 1,000 liters.
Q = (K * A * h / L) * 86,400 * 1,000
To calculate the cross-sectional area of flow (A), we need to know the dimensions of the pond. Let's assume the pond is a square with a side length of S meters.
A = S^2
Now we can calculate the flow rate per square meter of the pond bed:
Flow rate per square meter = Q / (S^2)
Substituting the given values:
Flow rate per square meter = (K * A * h / L) * 86,400 * 1,000 / (S^2)
We still need the value of the hydraulic conductivity (K) for the clay layer. Unfortunately, that information is not provided in the question. Without this value, we cannot calculate the flow rate accurately.
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