So the liquid level in the static pressure top taps.

In the case of a converging pipe is dropping like this,

the pressure is decreasing.

If we apply that now to a more complex situation where here I have a converging

pipe and the elevation is also increasing,

again I apply Bernoulli equation to the upstream station here,

which is one, and the downstream station two.

In this example, we also show the pipers converging.

Therefore the pressure is dropping.

The liquid level here in the static pressure taps is dropping.

If I draw a line through here I get a line which looks like that.

Each of these terms in the Bernouli equation has dimensions of length.

Some of those terms, p over gamma plus v squared over 2g plus c, is equal to

a length which is the height of the total head or the total energy of the flow.

And the height that that elevation reaches is called the energy grade line, or

the EGL, which is this line right here, is the energy grade line, EGL.