Short Notes River Training protection work

River Training and protection work :- The object of river training/protection work is to prevent the river from damaging railway Formation Bridge and other structure. The following type of river training works is generally adopted in the Indian Railway:-

a. Guide Bunds: Guide bunds are meant to confine and guide the river flow through the structure without causing damage to it and its approaches.

b. Spur/groyne : It is structure constructed transverse to the river flow and is projected from the bank of the river.

c. Marginal Bunds: these are provided to contain the spread of the river when the river in flood spills over the banks upstream of the bridge site over wide area and likely to spill in the neighboring water course or cause other damages.

d. Closure of Bunds: Some time it is necessary to entirely block one or more channels of the river in order to prevent, the discharge of such channel developing into a main river channel after the construction of bridge.

Protection of Approaches Banks:- 

1. Approaches banks of bridges may be subjected to severe attack under the following conditions.

(a) When HFL at bridge is very high and there is spill beyond the flow channel.

(b) When the stream meets a main river just downstream of bridge.

(c) In case of bridge with insufficient of water way.

In all the above cases the pitching of the approaches bank upto HFL with sufficient free board is an effective solution. Provision of toe wall and narrow apron, in some cases will also useful.

2. If deep borrow pits are dug near the toe to the approaches of the bank, the water flow through pits and forms a gradually deepening water course which may eventually threaten the safety of approach of the bank. In this case put rubble T-spurs across the flow to reduce the velocity.

3. All the location with standing water against the embankment, special watch should be kept when the water level recedes rapidly and when slip is likely to occur.