How do you calculate total head in ground water flow?

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Its attached below. I don't understand how you work out the total head. Can someone explain how you do it? I'm really struggling.

I know how to do the elevation, which is just the height above/below the datum level. And I've checked the solutions as well, it seems like you're supposed to work out the total head before the pressure head.
 
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  • Schematic cross-section of a dock beside a river: sheet piles, +6m OD dock water level, +1m OD river level, a silty sand layer above sandy gravel aquifer, points A, B and C in the sand, and piezometer level at point P in the gravel.
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What are the "total head", "pressure head" and "pore water pressure"?
Can you explain that to you grand-mother?
 
maajdl said:
What are the "total head", "pressure head" and "pore water pressure"?
Can you explain that to you grand-mother?

'head' is simply stress (or pressure) mulitplied by depth

for total head is the total pressure as it were
 
Do you think your grand mother could understand?
Could you explain those things in a tangible way?
For example, by comparing what you measure if free water versus water in a soil?

In addition, I don't think that "pressure x depth" is related to the "head".
As I am from Belgium, I am not used with this terminology.
However, I looked at http://en.wikipedia.org/wiki/Pressure_head and it looks like that "pressure head" is the height of fluid that would produce by gravity the same pressure. In some way, it is the pressure expressed in meters of fluid.

In a "Pressure Casserol", the pressure is unrelated to the depth of water insided the "Pressure Casserol". Yet, it can be expressed in head of fluid, and the numerical value might be meters while the "Pressure Casserol" would only be 20 cm high.

See also this picture, where head is shown by the measuring tubes.

Diagram of a horizontal pipe with a constriction, showing two vertical manometer tubes rising from the pipe; fluid levels differ, labelled h + Δh and Δh, with velocities v1 and v2 marked by red arrows.
 
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The head is defined as [itex]H=\frac{p}{ρg}+(z-z_0)[/itex], where z-z0 is the distance measured upward from the Ordinance Datum z0. So, at points P and C, the head H is 1 meter (there is no flow resistance between points P and C). At point A, the figure shows that the head is 6 meters above the Ordinance Datum. At point B, because the flow is steady, the head is the average of points A and C, or 3.5 meters. The upward seepage velocity is given by:

[tex]v=- K\frac{(H_A-H_C)}{(z_A-z_C)}[/tex]

where K is the hydraulic conductivity (10-4 m/s).