# Pressure in irrigation water pipe

I would like to know the pressure at the bottom of the pipe which I use for irrigation purpose. The land is step cultivated and the pipe goes slanting for the length of 140 meters and the top height would be 45 meters, water is pumped out from borewell using 7.5 hp submersible pump. I would like to know the pressure at the bottom of the pipe (Surface of the land, borewell depth can be ignored) when the water reaches the top.

• use pressure = density * gravity * height. google this as there are several calculators available on the web.
– user207455
Commented May 16, 2019 at 9:11
• Use may also want to "Google" Bernoulli equation: $p+\frac{1}{2}\rho v^2 + \rho \mathrm{g}h = k$ Commented May 18, 2019 at 12:43

It will be the pressure that you find at 45 meters depth in water, that is 543 kPa or equivalently 5.28 atm (my reference).

I think that when the flow of water in the pipe changes rapidly this value will change.

The result is a consequence of the fact that the gradient of pressure into a static liquid is proportional to the gravitational field (or the gradient of the total potential).

I gave in my comment :

use pressure = density * gravity * height. google this as there are several calculators available on the web.

Using 1000kg/m^3 for density, 9.81m/s^2 gravity and 45m

Pressure = 1000 * 9.81 * 45 = 441450 pa

converted to atm is 4.41

Different slightly to the result in the link, as I assumed 1000kg/m^3 for the density.

So, here is one link, out of many possible: