![For a symmetrical trapezoidal open drain in a landscape with grass and loose rock surface, the velocity of flow of water is m/sec](https://www.gkseries.com/blog/wp-content/uploads/2023/07/For-a-symmetrical-trapezoidal-open-drain-in-a-landscape-with-grass-and-loose-rock-surface-the-velocity-of-flow-of-water-is-m-sec.jpg)
Q. For a symmetrical trapezoidal open drain in a landscape with grass and loose rock surface, the velocity of flow of water is m/sec, (rounded off to two decimal places), given the following data.
Water edge width at the top= 750 mm
Water edge width at the bottom = 450 mm
Water depth = 600 mm
Manning’s coefficient of roughness = 0.05 Slope along the
drain= 1 in 250
A. 4.5
B. 0.45
C. 45
D. 1.5
Ans: 0.45
Solution:
![](https://www.gkseries.com/blog/wp-content/uploads/2023/07/image-150.png)