$($b$)$ Using the tractive approach, design a stable channel lining which will protect against erosion during a $\backslash (100\backslash$mathrm$\{$~m$\}^\{3\}/\backslash$mathrm$\{$s$\}\backslash )$ design flood travelling through the town of Ennui$-$sur$-$Blas$$ if this section of the river is $5$ m wide, trapezoidal in cross$-$section, with sides slopes as shown in Fig Q$2\mathrm{.}3,$ and bed slope of $1$ in $1000.$

Make reasonable assumptions for information that is missing. Comment on the reliability$/$accuracy of your design and outline alternative approaches which may be suitable.