Lecture 13

Fresh Water Head

Fetter 5.4

What if the density of the water 1, then pressure head dependent on density, as well.

Fresh Water Head - Hydraulic head measured in a piezometer in a fresh-water aquifer.

Point Water Head - Includes pressure-head effects due to density.

Use the equivalent fresh-water reads to determine gradients in a variable density flow

system (correct for density ‘Normalize" to get flow).

	Must assume no lateral change in density.
		Would imply density a gradient that contributes to lateral flow.

Total hydraulic head = elevation head + pressure head

(Fresh water Head)

	First measure point-water head,
	then calculate fresh-water head.
	See following figure.

Figure 5.3. Definition of point-water head and fresh-water head.

Must convert point-water heads to equivalent fresh-water heads before

calculating gradients or contouring.

Usually when we say weight we are measuring mass which already accounts for g

Force Potential - total potential energy in a flow system as a total of mechanical

energy kinetic energy, elevation energy, and pressure.

Phi - F
	Since, h = z + hp

Figure 5.5 Apparatus to demonstrate how changing the slope of a

pipe packed with sand will change the components of elevation, z,

and pressure, h_p, heads (Diagrams A, B, C, D)

*Q construction, pipe filled with sand, rotate pipe.

ENV 302 - Lectures