- Manholes: it is a masonry chamber built in a sewer, of
such a size, that a man can enter in it or leave it for
carrying out inspection, repair, cleaning, testing, or joining
of other sewers. It also gets connections from soil wastes,
liquid wastes, and ventilating shafts.
It can be square, rectangular or circular in shapes. For detail
sections of these manholes see figure 11.5. Its depth goes on
increasing along with the falling gradient of the sewer.