Field machine index (FMI) is defined as the percentage ratio of effective operating time of a machine to the sum of effective operating time and time lost in turning at headlands:

Where $T_e$ is effective operating time and $T_t$ is turning time. It measures how effectively turning time is minimized during field operations.

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/$\text{m}^3$.

During border strip surface irrigation, water flows as a thin sheet over the soil surface. Because water infiltrates into the soil continuously along the path of advance, the discharge rate decreases along the flow length ($dQ/dx \lt 0$, spatially varied flow). Furthermore, at any given cross section, the depth and flow velocity vary over time ($dQ/dt \ne 0$). Therefore, overland flow in a border strip is an example of spatially varied unsteady flow with decreasing discharge.