How is pressure calculated from elevation difference in irrigation systems?

Pressure in irrigation systems due to elevation difference can be determined using the basic principle that relates height (or head) of water above a point to the pressure exerted at that point. This relationship is grounded in the hydrostatic pressure formula, where pressure is equal to the product of the height of the water column and the specific weight of the water.

In general, the specific weight of water is approximately 62.4 pounds per cubic foot or 9.81 kilopascals per cubic meter. Given that pressure is often expressed in pounds per square inch (psi) and that 1 psi is equivalent to the pressure exerted by a column of water that is about 2.31 feet high, the relationship can be simplified to express pressure in terms of height.

Thus, when using the formula P = 0.433H, we derive that one foot of water creates approximately 0.433 psi. This indicates that for every foot of elevation difference (H) in the water column, the pressure increases by about 0.433 psi. Therefore, using this conversion factor, it becomes clear that the calculation of pressure from elevation difference in irrigation systems correctly follows the equation noted in the answer choice.

This understanding is crucial in irrigation