Q. How to design banks?

When approach banks are of medium height upto 3 m, the material may be homogeneous. For bigger heights zoned section with impervious core and pervious outer sections may be desirable.

Foundation should provide a stable support for overlaid bank and should resist harmful percolation. Unconsolidated material in foundation is liable to settlement and percolation of water. Cut off trenches backfilled with rolled impervious material, sheet pile cut off, grouting, clay blanket on upstream side and inverted filter on downstream side are helpful in minimising harmful effect of percolation.