Which is correct for the guide bank plan?

Upstream shank 1-1.5W, tail 0.2-0.5W, head radius about 0.5W with sweep 120-145 degrees

Top level, width and slopes of the guide bank?

HFL + 1.5 m, width 6 m (3-6), 2:1 river side (3:1 at head)

Pitching thickness and scour depth formulas?

t = 0.06 Q^(1/3); R = 0.47 (Q/f)^(1/3), 2R at nose and 1.5R at shank

What does the launching apron do?

As the bed scours, stones slide down the 2:1 slope protecting the bund from undermining

2062 Baisakh (old course) · 1+2+5 marks

RT works, methods and guide bank components

Define river training works. Enumerate different methods of river training works. Explain the design of different components of a guide bank.

Definition (1 mark)

River training works are structures built on or along a river to guide the flow, stabilise its course, protect its banks and safeguard structures like bridges and barrages from floods and erosion.

Methods (2 marks)

Guide bunds (guide banks).
Spurs (groynes).
Marginal embankments (levees).
Bank pitching (revetment) with a launching apron.
Cut-offs.
Bed sills, check dams and bio-engineering.

Design of the components of a guide bank (5 marks)

Waterway: Lacey's regime width $W = 4.75\sqrt{Q}$ (Q in m³/s). Silt factor $f = 1.76\sqrt{d_{mm}}$ .

Component	Design
Length of guide bank	Upstream shank $1.0$ to $1.5W$ ; downstream tail $0.2$ to $0.5W$
Curved head	Radius about $0.5W$ (upstream), sweep $120$ to $145^\circ$ ; downstream sweep about $45^\circ$
Top level and width	HFL $+ 1.5$ m free-board; width 6 m (3 to 6 m)
Side slopes	2:1 river side (3:1 around the head); 2:1 country side
Pitching	Thickness $t = 0.06Q^{1/3}$ on 0.15 to 0.3 m graded filter
Scour depth	$R = 0.47(Q/f)^{1/3}$ ; $2R$ below HFL at nose, $1.5R$ at shank
Launching apron	Depth below bed $D' =$ scour depth $-$ flood depth; width $1.5D'$ ; launched thickness $1.5t$ (laid about $2.25t$ )

 Section at shank
      _6 m_
     /     \  HFL+1.5 m
 HFL/_______\ 2:1
   / pitching \
 _/___filter___\_ apron (width 1.5D', launches at 2:1)

The apron is laid at the toe of the pitching and, as the river scours the bed, the stones slide down the 2:1 slope and protect the bund against undermining.

✓ Answer checked by Claude Opus 5.5 (high effort)

Objectives of river training works · Irrigation and Drainage Engineering, chapter 6
Guide bank design, 4000 m3/s, d 0.40 mm · Irrigation and Drainage Engineering, chapter 6
Guide bank design, 6500 m3/s · Irrigation and Drainage Engineering, chapter 6
Define RT works, objectives, purposes of spur · Irrigation and Drainage Engineering, chapter 6
Objectives of RT works and spur spacing · Irrigation and Drainage Engineering, chapter 6
RT works for a bridge; launching apron · Irrigation and Drainage Engineering, chapter 6
Bridge components sketch; river bank protection · Transportation Engineering II, chapter 5
Building near river bank; stop construction? · Engineering Professional Practice, chapter 7
Dry and wet river intakes; unstable bank · Water Supply Engineering, chapter 5
Bridge site factors; river bank protection structures · Transportation Engineering II, chapter 5

All Irrigation and Drainage Engineering chapter 6 questions →

RT works, methods and guide bank components

Definition (1 mark)

Methods (2 marks)

Design of the components of a guide bank (5 marks)

Related questions