Given:

contracted$\_$weir with both sides being contracted

weir:crest$\_$height $x$ is equal to $6\mathrm{.}0[m]$

crest$\_$L $($or width if you like$)=6\mathrm{.}0[m].$

Discharge coeffieint C$\_$D $=1\mathrm{.}57[\frac{m^{0\mathrm{.}5}}{s}].$

Q$\_$design$\_$Head$=1\mathrm{.}3[$m$]$; upstream of weir.

What is the crest$\_$height$=?[$m$]$ of a standard U$.$S$.$B$.$R $($US Bureau of Reclamation$){90}^0\_$

$V-$notch replacement weir if we require

same discharge;

same total upstream$\_$depth

Definitions:

type:contracted$\_$weir

length $($or width if you like$)$ horiz and vertically contracted for flow$\_$over$\_$crest.

Weir may be contracted at either or both ends. Equation$\_$general:

$Q=C(L-n\frac{H}{10})H^{\frac{3}{2}}$

$L=$width $($or length$)$:weir$\_$crest, $C=$ Q$\_$coeff, $==$# of contractions $($either $1$ of only on

one side and $2$ if on both sides$)$; $H=$head$\_$over$\_$weir. U$.$S$.$B$.$R offers:

$Q=1\mathrm{.}34H^{2\mathrm{.}48}($for SI units$)$

for Q$\_90$ V$-$notch weir.