At the foot of a spillway, water flows at a depth of $23 \: cm$ with a velocity of $8.1 \: m/s$, as shown in the figure.
The flow enters as an $M-3$ profile in the long wide rectangular channel with bed slope $= \frac{1}{1800}$ and Manning’s $n=0.015$. A hydraulic jump is formed at a certain distance from the foot of the spillway. Assume the acceleration due to gravity, $g=9.81 \: m/s^2$. Just before the hydraulic jump, the depth of flow $y_1$ (in $m$, round off to $2$ decimal places) is _________