Pick up the incorrect statement from to following regarding triangular notch :

ANS:C - Ventilation is necessary

The incorrect statement regarding the triangular notch is:

• For measuring low discharge, it gives more accurate results.

Triangular notches are primarily used for measuring relatively higher discharge rates, and they may not provide accurate results for low discharge rates. For low discharge rates, other types of weirs or devices may be more suitable. Therefore, the statement suggesting that triangular notches give more accurate results for low discharge rates is incorrect.