Flow taking place through a rectangular channel, having width $=20m$ and the depth $=0\mathrm{.}3m.$ There is an error in measurement of

Manning's roughness coefficient and bed slope of the channel. The measured Manning's roughness coefficient $=0\mathrm{.}03$ with a

variation range from $0\mathrm{.}027$ to $0\mathrm{.}033$ and bed slope is $0\mathrm{.}0003$ with a range from $0\mathrm{.}00027$ to $0\mathrm{.}00033.$ Determine the error in discharge

computation. Also states which parameter requires to be measured precisely to reduce the error in discharge measurement.