- Use a 2mm Thick Mild Steel plate to make the V notch. Make a 90o V
- Water surface downstream of the weir should be at least 6 cm below the bottom of the V to allow a free flowing waterfall.
- The bottom of the "V" only needs to be 10 cm (=P) above the bottom of the upstream channel,
- the approach channel (=B) only needs to be 2 ft. wide,
- Head (h) should be measured at a distance of at least 4h upstream of the weir.
Q = 4.28 Ctan(θ/2)( h+k)5/2
where
Q = flow rate (cfs)
C= Discharge Coefficient,C=0.578 for 90o V notch
θ= v-notch angle ( 90o h = head on the weir (ft)
k = Head Correction factor(Ft)
- k (ft.) = 0.0144902648 - 0.00033955535 Ø + 3.29819003x10-6 Ø2 - 1.06215442x10-8 Ø3
where Ø is the V notch angle in degrees ( 90o
Source: ENVO PROJECTS. NEW DELHI-25 9899300371, 9810004529