Irrigation, Drainage & Pumping Systems

Water conveyance efficiency ($\eta_c$) evaluates water transmission losses in canals, flumes, and field channels:

Where:
$W_f$ = Water delivered to the irrigation plot or farm headgate
$W_r$ = Water delivered or diverted from the river/reservoir source
It accounts for conveyance losses such as canal seepage and evaporation.

Water Use Efficiency (WUE) is defined as the yield or marketable crop production obtained per unit of water applied (or evapotranspired):

Where $Y$ is crop yield/production (kg/ha) and $W$ is water applied or consumed (ha-mm or $\text{m}^3$). It is generally expressed in kg/ha-mm or kg/$\text{m}^3$.

In sprinkler irrigation design, Christiansen's Uniformity Coefficient ($C_u$) indicates the spatial uniformity of water depth collected in catch cans across the irrigated area:

For acceptable irrigation performance under normal wind velocity (less than 8 km/h) and rated nozzle operating pressure, an 80% to 85% uniformity coefficient is considered the minimum acceptable standard.