path as it flowed out from the end of the sewer can then be
drawn out for the various depths, taking into account the fact
that the velocity at the invert and sides of the sewer is less
than the average velocity of flow. The ramp should be built in
accordance with the calculated curves so as to avoid splashing
as far as possible, and the level of the trough C fixed so that
when it is placed sufficiently far from A to allow the dry
weather flow to pass down the ramp it will at the same time
catch the storm water when the required dilution has taken
place. Due regard must be had to the altered circumstances
which will arise when the growth of population occurs, for
which provision is made in the scheme, so that the overflow
will remain efficient. The trough C is movable, so that the
width of the leap weir may be adjusted from time to time as
required. The overflow should be frequently inspected, and the
accumulated rubbish removed from the trough, because sticks and
similar matters brought down by the sewer will probably leap
the weir instead of flowing down the ramp with the sewage. It
is undesirable to fix a screen in conjunction with this
overflow, but if screening is essential the operation should be
carried out in a special manhole built lower down the course of
the storm-water sewer. Considerable wear takes place on the
ramp, which should, therefore, be constructed of blue
Staffordshire or other hard bricks. The ramp should terminate
in a stone block to resist the impact of the falling water, and
the stones which may be brought with it, which would crack
stoneware pipes if such were used.

In cases where it is not convenient to arrange a sudden drop in
the invert of the sewer as is required for a leap weir