What pressure increase is expected per foot of elevation gain in an irrigation system?

• A. 1 psi
• B. 0.433 psi
• C. 2 psi
• D. 0.5 psi

Answer: (B)

In an irrigation system, the pressure change that occurs due to elevation gain is a critical factor in calculating the overall system performance. It is established that for every foot of elevation increase, there is a pressure loss or increase of approximately 0.433 psi. This figure is derived from the principles of hydraulics, specifically how water pressure changes with elevation due to the weight of the water column above the point of measurement.

When water is lifted, gravity exerts a force that correlates to this specific pressure drop or gain based on the height, meaning that for each foot of vertical distance that water must be moved upward, the pressure decreases by 0.433 psi. Conversely, if water is falling or the outlet is higher than the source, the pressure increases by the same amount. This foundational knowledge is essential for designing efficient irrigation systems that can optimize water delivery under various topographic conditions.

Understanding this concept allows landscapers and irrigation specialists to make informed decisions about system design, ensuring proper water pressure at the delivery points, ultimately leading to more effective and efficient watering.