$(8)$ A stream with DO hes flow of $1\mathrm{.}2\frac{m^3}{s},BO{D}_5$ if $4m\frac{g}{L}$ and

reoxyghation constant of $0\mathrm{.}3d^{-1},M-$receives an effluent discharge

of $0\mathrm{.}25\frac{m^3}{s}$ having $BO{D}_5$ of $20m\frac{g}{l_1}D{O}^4{L}^{5}m\frac{g}{L}$ and deaxygenatim cmitat

$0\mathrm{.}13d{t}^{-1}.$ The average velocily of flow of th strean $450\mathrm{.}18\frac{m}{s}.$ Calculte

Do definit at print $50$ km downstream, tamb can be taken as $20C.$ Ame

$me{D}_{\text{s}\text{u}\text{t}}=g\mathrm{.}2m\frac{g}{L}$