A rectangular open channel of $\text{6 m}$ width is carrying a discharge of $20 \text{ m$^{3}$/s}$. Consider the acceleration due to gravity as $9.81 \text{ m/s}^{2}$ and assume water as incompressible and inviscid. The depth of flow in the channel at which the specific energy of the flowing water is minimum for the given discharge will then be
1. $\text{0.82 m}$
2. $\text{1.04 m}$
3. $\text{2.56 m}$
4. $\text{3.18 m}$