Distance (\( x = \frac{qt}{k_1 D_0 + k_2 y_0} \)):

Where:

• \( x \) is the distance to the leading edge.
• \( q \) is the unit stream size or flow per unit width of the border strip, in gallons per minute (gal/min).
• \( t \) is the total time of flow, in hours.
• \( D_0 \) is the depth of water at the upper end, in meters (m).
• \( y_0 \) is the cumulative intake at the upper end, in meters (m).
• \( k_1 \) is the surface storage coefficient, varying from 0.5 to less than 1.0.
• \( k_2 \) is an additional coefficient.