Summary:

The aim of the research was to determine the rain water volume which infiltrates
through the holes in the sewage chambers inside the pipes of the separate
sewer system. Incorrect paving or the sewer chambers envois cause the chambers'
surfaces deepen in the area surface. The water which flows down during the rainfall
or the snow melt, infiltrates inside the chamber through the cleavages, but
mainly through the technical holes in the hatches. These holes are used for the key
or the lever to raise or to open the lid of the hatch.
The field analyses showed that many sewage chambers are made incorrectly.
In many cases the hatch's lid is located from 10,6 to 38,3 mm below the
area surface. It causes the rainfall or the snowmelt water to overflow through the
cleavages or through the holes in the hatch to the sewage chamber. On the basis
of the laboratory analyses, it was ascertained that the inflow of the precipitation
water to the sewage chamber, by the hole used to raise the lid, can be described by
the following equation: Q = 25 · h2 + 7,7679 · h, in which h is the immersion of the
hatch below the area surface.
The research showed that with the long-term rainfalls or the surface flows
related to the snowmelt season, the technical holes in the sewage chambers'
hatches, located incorrectly below the area surface, can be the essential reason for
the accidental waters' inflow to the household sewerage system. This indicates the
need to be more careful during the lid's production and during the work on the
damaged paving reconstruction.