The existing grade and contours of any parcel,
plot or lot shall not be altered or modified by excavating, grading,
terracing, filling or any other means whatsoever except to provide
necessary ingress thereto and egress therefrom or in conjunction with
the sinking of foundations, footings, utility lines, cesspools and
similar subterranean or partially subterranean structures constructed
as an accessory or appurtenance to a use permitted in the building
zone. After the installation of such structures, the terrain shall,
except where it has been lawfully built over, be restored to its original
contours.
Where necessary to provide adequate ingress
to and egress from premises, the grade may be lowered or raised not
to exceed five feet measured to the finished surfaces of actual walkways
or driveways used for ingress and egress.
Where all or any portion of any open excavation
now or hereafter made, whether or not it shall contain a structure
of any sort, shall be more than 29 inches in depth from its bottom
to the top of its lip or edge, such excavation or any such portion
of any excavation shall be provided with a surrounding enclosure not
less than four feet in height, which shall be so constructed as to
prevent access to such excavation or portion thereof through or beneath
such enclosure and to hinder, impede and obstruct access thereto by
climbing or scaling such enclosure.
Where any construction, excavation or fill shall,
or may according to recognized engineering standards and principles,
act to divert or increase the course or amount of run-off water to
public land, streets or land of another, or where liquid industrial
or commercial waste of any sort shall be created, adequate provision
shall be made for the containment of all such waters and wastes or
their diversion to other than sanitary sewers, streets, public land
or land of another.
Where any construction or excavation shall,
or may according to recognized engineering standards and principles,
cause public land, streets and land of another to be eroded or to
subside, adequate retaining structures shall be provided to prevent
such erosion or subsidence.