Elevation affects irrigation design primarily by influencing:

• A. Sun exposure of the site.
• B. Electrical costs for pumps.
• C. Water pressure and head when delivering water to elevated zones.
• D. Soil texture per zone.

Answer: (C)

Elevation changes the energy required to push water to higher points. In irrigation design, the key issue is the hydrostatic head created by raising water up to elevated zones. The higher the target area, the more pressure is needed at the source to maintain the same emitter flow and coverage. If the supply pressure isn’t enough to overcome this lift, higher zones will receive less pressure, leading to weaker spray or missed irrigation. Therefore, planning must account for the vertical rise between the water source and the furthest emitters, potentially using a bigger pump, booster pump, or dividing the system into zones with appropriate pressure.

Sun exposure, soil texture, and electrical costs are less about the hydraulic effect of elevation. Sun exposure affects evapotranspiration and plant water needs, soil texture affects infiltration and distribution uniformity, and electrical costs relate to pump size and run time rather than elevation alone (though head requirements do influence pump sizing).