The length of a rectangular weir is L and height $$H_1$$. The maximum depth of water on the upstream side of the weir is H. Flow rate over the notch (Q) is

A

$$Q = \frac{2}{3}c_d L\sqrt{2g}H^{\frac{5}{2}}$$

B

$$Q = \frac{2}{3}c_d L\sqrt{2g}(H - H_1)^{\frac{5}{2}}$$

C

$$Q = \frac{2}{3}c_d L\sqrt{2g}H^{\frac{3}{2}}$$

D

$$Q = \frac{2}{3}c_d L\sqrt{2g}(H - H_1)^{\frac{3}{2}}$$