Drainage formula (Water Overlay)

Drainage passive: First the flow capacity is calculated $Q_{p,t}=\Delta t*q_{t}$

Failed to parse (unknown function "\abs"): {\displaystyle Q_{b} = A_d \cdot f_s \cdot \abs{\frac{(w_g - w_w) \cdot A_w}{A_d \cdot f_s + A_w}}}

$Q_{max}=A_{d}*(w_{d}-z_{d})*f_{s}$ $where::<math>w_{g}$ is the ground water level in meters

$w_{w}$ is the water level in the waterway

$z_{d}$ is the drainage datum height in meters.

$A_{d}$ is the drainage area size in square meters.

$f_{s}$ is the average storage percentage of the ground above the drainage.

$Q_{b}$ is the amount transfered for a balanced ground and surface water level

<math>Q_{max} is the amount available in the ground above the drainage.

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