EMBANKMENT AS RIVER TRAINING WORK
The embankments, discussed earlier, are fragile works indicating an inherent weakness of this method of river training and control. Their merits and demerits as river training work are as under:
Advantages: (i) Only means of preventing inundation on tidal plains, (ii) Low initial cost, subsequent raising may be possible, (iii) Easy construction, making use of locally available material and unskilled labour, (iv) Maintenance simple and economical, (v) Can be executed in parts, provided that the ends are properly protected.
Disadvantages: (i) Cause raising of high flood levels, (ii) Possible to boring by crabs and worms resulting in failure by piping, (iii) Need close supervision during floods, (iv) In the event of a breach, there is a sudden and considerable inflow of water which may cause damage and deposition of sediments rendering the area unproductive, (v) Susceptible to direct attack of river flow which can erode or undermine them, (vi) Low lying areas may become infected with malaria, if proper drainage facilities are not provided, (vii) In rivers carrying a considerable sediment charge, embankments exclude silt deposition on the flood plain, extension of the delta towards the sea is thus hastened, resulting in the increase of flood stages and the rate of aggradations of river bed.