Agricultural Drainage

In an unsteady state subsurface drainage scenario governed by the Glover-Dumm equation, the mid-spacing water table height above drain level decays as $h_t = \frac{4}{\pi} h_0 e^{-\alpha t}$, where drainage factor $\alpha = \frac{\pi^2 K d}{\mu L^2}$. An initial water table rise of $h_0 = 1.20\text{ m}$ must be lowered to $h_t = 0.60\text{ m}$ within $t = 2.0\text{ days}$. The soil has hydraulic conductivity $K = 1.00\text{ m/day}$, equivalent depth $d = 2.00\text{ m}$, and drainable porosity (specific yield) $\mu = 0.050$. Taking $\pi = 3.1416$, the required drain spacing $L$ in meters is ________ (round off to one decimal place).