"The surface drainage is something that interests us whenever it rains
or when the snow melts. It has been customary to locate catch-basins for
receiving the surface water at street intersections. This arrangement
causes most of the surface water from both streets to run past the
crossings, making it necessary to depress the pavement, so that one must
step down and up in going from one side of a street to the other, or
else a passageway for the water must be made through the crossing. It
may be said that a step down to the pavement and up again to the
sidewalk at the street intersections is of no consequence, but it is
really more elegant and satisfactory to have the walk practically
continuous (Fig. 68). With the catch-basin at the corner, the stoppage
of the inlet, or a great fall of rain, sometimes covers the crossing
with water, so one must either wade or go out of his way. With
catch-basins placed in the center of the blocks, or, if the blocks are
long, at some distance from the crossing, the intersections can be kept
relatively high and dry. Roadways are generally made crowning in the
center so that water runs to the sides, but frequently the fall
lengthwise of the roadway is less than it should be. City engineers are
usually inclined to make the grade along the length of a street as
nearly level as possible. Authorities who have given the subject of
roads considerable study recommend a fall lengthwise of not less than
one foot in one hundred and twenty-five, nor more than six feet in one
hundred. Such grades are not always feasible, but a certain amount of
variation in level can usually be made in a residence street which will
make it much more pleasing in appearance, and have certain practical
advantages in keeping the street dry. The water is usually confined to
the edge of the pavement by curbing, which may rise anywhere from four
to fourteen inches above the surface. This causes all the water falling
on the roadway to seek the catch-basin and be wasted, excepting for its
use in flushing the sewer. If the curbing, which is really unnecessary