River training structures are used to guide and direct river flow, regulate the river bed, and increase water depth. The objectives are to provide safe passage for floods, prevent river bank erosion, improve channel alignment, and efficiently transport sediment. Common structures include embankments, guide banks, groynes, cutoffs, pitched islands, and bandalling. Groynes can be impermeable or permeable, classified based on their height, functions like attracting or repelling flow, and some have special designs like T-heads or hockey shapes.

1. RIVER TRAINING STRUCTURES
Prof. V. S. Chaudhari
Assistant Professor
Department of Civil Engineering
Sanjivani College of Engineering, Kopargaon 423 603

2. River Training Structures
• River training implies various measures adopted on a river to direct and
guide the river flow, to train and regulate the river bed or to increase the
lower water depth.
Purpose:
• To stablish the channel along a certain alignment.
• The importance of river depends upon its length, width, velocity and
seasonality.
• Some rivers are short like, most of the river flowing in western
direction in South India (called as Konkan-river like Surya, Tanasa,
Savitry, kat etc.)
• Their utility is lesser than the river in North India, like Ganga, Yamuna,
Brahmaputra etc. which are long and are perennial.

3. Objectives of River Training
• To provide a safe passage to the flood discharges, without over flowing
to the banks for protection of cultivated & in habited areas.
• To prevent out flanking of a work, like bridges weir or any aqueduct.
• To protect the river banks from heavy erosion, and to improve the
alignment by stabilizing the river channel.
• To transport the bed & suspended sediments load with a maximum
efficiency.
• To deflect the river away from the bank which it may attack.

4. Classification of River Training Work:
On the basis of purpose:
A) High water training: To dispose off the flood water and to provide
protection against any type of damage due to such flooding i.e.
training for discharge.
B) Low water training: To provide, sufficient depth of water for the
Inland Navigation, during the low water season i. e. during summer
for the non perennial rivers, mainly in South India i.e. training for
depth.
C) Mean water training: A smooth disposal of bed & suspended
sediments load and to maintain the shape of the channel i.e. training
for sediments.

5. Methods of River Training
A) Marginal Embankments: They are the earthen constructions which
built to continue the flood water, within the c/s available between these
embankments.
Effects of Marginal Embankments on the flooded river:
• To increase the velocity of flood water, to move in downward direction.
• To increase the surface elevation during floods.
• To increase the velocity of discharge at all the d/s points.
• To increase the water surface slope of the stream of u/s leveed portion.

6. B) Guide Banks or bunds:
• These are the earthen embankments to channelize the flood water of the
river.
• In India such types of bunds were designed first by Bell, so known as
Bell’s Bunds. Further modified by Spring and Gates.

7. C) Groynes or Spurs: It is a structure, constructed, transverse to the
river flow. It extend from the bank into the river.
Functions:
• To protect the river bank by keeping the flow away from it.
• To construct a wide channel for making the river navigable.
• To train the river along the desired course by attracting, deflecting or
by repelling flow in the river.
• To create a slack flow with the objective of silting up the area in the
vicinity.

8. Classification of Groynes : different criteria's
Based on:
a) Methods and Materials:
1. Impermeable Groynes: Don’t allow the flow of water through them,
side slope vary between 2:1 to 3:1
2. Permeable Groynes: They allow a restricted flow of water through
them.

9. b) Height of Groynes:
1. Non-submerged Groynes: above or below the surface of river.
2. Submerged Groynes
c) Functions:
1. Attracting groynes:
A groynes which point out
d/s, tend to attack the river
flow toward the bank on
which it has been provided.

10. 2. Repelling groynes: It tend to repel
the river flow, away from the bank.
3. Deflecting groynes: They are either
perpendicular to the bank or pointing
slightly u/s have short length.
4. Sedimenting groynes: A river carry
considerable amount of sediments.

11. d) Special type of Groynes:
1. Denehy’s T-headed groynes:
These type of report first used
at okhla Head works on Yamuna
river in Delhi in 1880.
2. Hockey Head or groynes: These
are provided with a curved head,
such as, it looks like a hockey
stick.

12. D) Cutoffs:
• A alluvial river, flowing along a
curve or bends abandons a
particular bend and establishes
its main flow, along a straight and
a shorter channel.
• The ratio of length of the bend to that of chord is called cutoff ratio.
• When ratio exceeds 1.5 to 2.5 a natural cutoffs take place.

13. E) Pitched Island:
• It is a artificially constructed
island in a river bed.
• It consists of sand-core, which is
protected by stone pitching on all
sides of the island.
• They work as a guide bank.

14. F) Other Methods/Bandalling:
• It is applied to low water flow
in a single channel for
maintaining the required depth
for the Island navigation.