## Culvert

We'll be using box culvert for this modelling:

- Reach length: 100m
- Channel slope: 0.003
- Downstream XS: (5, 80), (5, 75), (45, 75), (50, 80)
- Mannin's n: 0.013
- Culvert's u/s is at 50 m (10 m d/s from 60 m)
- Culvert is 10 m in width (or length in the perspective of river length)

![[Pasted image 20260723132117.png]]

### General

- Culvert opening called barrel

### Procedure

- Keep SI unit

#### Geometric

- Enter u/s and d/s cross sections
- Interpolate by 20
- Open "Bridge/Culvert"
	- Options > Add Bridge/Culvert
		- Enter cross section: 50
	- Deck/Roadway
		- Distance: 10
		- Low chord: Same or less than ground elevation
		  ![[Pasted image 20260723132952.png]]
	- Culvert
		- Shape: Box
		- Span: 9 (each box width)
		- Rise: 4 (height of box)
		- Chart: #59 - Rectangular concrete
		- Scale: #1 - Side tapered
		- Distance to u/s xs: 10
		- Culvert length: 10 (may be different than deck width if culvert extends outwards/inwards from the deck)
		- Depth block: block flow upto depth (use 0)
		- U/s & d/s invert elv: floor elevation (bottom elv within the section)
		- Total 3 barrels in 40 m (station 5 to 45); 13 dist; 5 18 31 45; mid point 11.5, 24.5, ...
		  ![[Pasted image 20260723140556.png]]

#### Steady Flow

- 3 flow profiles: 250, 500, 750
- Reach boundary conditions:
	- U/s: Normal depth - 0.003
	- D/s: Critical depth

#### Analysis

- Use mixed condition

#### Observation

- At PF 2 and 3, overflows