This question was previously asked in

MPSC AE CE Mains 2019 Official (Paper 2)

Option 2 : L = C√Q

ST 1: Building Construction and Materials

1095

20 Questions
40 Marks
24 Mins

__Explanation:__

**Linear waterway:**

- It is defined as the width of the waterway between the
**extreme edges**of the water surface at H.F.L. measured at right angles to the abutment face.

Effective linear waterway:

- It is defined as the total width of the
**waterway of the bridge**at**H.F.L.**minus the**Waterway effective width of obstruction.**

**As per IRC-5, waterway (W) should be equal to Lacey’s regime waterway (P) given by the equation:**

**P = W = C×Q ^{1/2}**

Where**, P** = Wetted perimeter in meters,** W** = Linear waterway in meters, **Q _{d}** = Design discharge in m

**Note: **The code also stipulates that the waterway so found should also be **compared with the linear waterway at HFL** corresponding to design flood discharge and the** minimum** of the two should be adopted as the clear waterway under the bridge.