Water Distribution Efficiency (\( \xi_d \)):

\[ \xi_d = 100 \left( 1 - \frac{y}{d} \right) \]

Where:

• \( \xi_d \) is the water distribution efficiency, in percentage (%).
• \( y \) is the average numerical deviation in depth of water stored from the average stored during irrigation, in millimeters (mm).
• \( d \) is the average depth of water stored during irrigation, in millimeters (mm).