Agricultural Drainage

Using Hooghoudt's steady-state drainage equation $S^2 = \frac{4 K_1 m^2 + 8 K_2 d m}{q}$, compute the required drain spacing $S$ in meters for an agricultural field with hydraulic conductivity of upper layer $K_1 = 1.0\text{ m/day}$, lower layer $K_2 = 1.0\text{ m/day}$, equivalent depth $d = 2.0\text{ m}$, water table height above drains midway $m = 1.0\text{ m}$, and steady recharge rate $q = 0.005\text{ m/day}$. The drain spacing $S$ in meters is ________ (round off to nearest integer).