# Determine the water flow rate per day at the mouth of the river, which flows at a speed of 0.6 m / s, has a depth of 1.8 m

**Determine the water flow rate per day at the mouth of the river, which flows at a speed of 0.6 m / s, has a depth of 1.8 m, a width along the water surface – 7.5 m, and along the bottom – 4.5 m.**

Water discharge is the volume of water that flows per unit of time through the cross section of a river. It is determined by the formula: Q = F × V, where F is the cross-sectional area of the river, V is the current velocity.

1) The cross-section of the river is trapezoidal. The area of the trapezoid is determined by the formula:

S = (a + b): 2 × h = (7.5 m + 4.5 m): 2 × 1.8 m = 10.8 m2

2) Determine the flow rate in the river for 1 s:

Q = F × V = 10.8 m2 × 0.6 m / s = 6.48 m3 / s

3) Water flow per day is: 6.48 m3 × 60 s × 60 min × 24 h = 559 872 m3 / day

Answer: water discharge at the river mouth = 559,872 m3 / day.