Roof drains and sump pumps shall discharge to infiltration or
vegetative BMPs and to the maximum extent practicable satisfy the
criteria for disconnected impervious areas (DIAs). When it is more
advantageous to connect directly to storm sewers, such connections
may be permitted by the Township. Roof drains shall not discharge
directly to streets. Sump pump and roof drain/downspout connections,
when determined to be more appropriate for direct connection to storm
sewers shall be as follows:
A. Sump pump drainage.
(1) Within all subdivisions and land developments, structures which will
have basements or crawl spaces shall be required to have sump pumps
installed by the developer, his agent, builder or builders. In addition
thereto, the owner of any lot or group of lots erecting and constructing
any structure which contains a basement shall be required to install
a sump pump in conformity and in compliance with this section.
(2) Sump pump drainage from structures shall be connected via underground
storm drainage to the storm drainage system of the lot. The waiving
of the requirements of the installation of a sump pump shall only
be by the site investigation to determine the conditions of the water
table, springs in the substrata within the location of the proposed
basements, and the investigation shall be made and determined by the
Township Building Inspector or the Township Engineer, and the cost
of this investigation shall be entirely borne by the developer, his
agent, builder or builders or the owner of a one-lot structure or
group of lots involving a basement.
(3) The minimum size discharge line for underground storm facilities
shall be a four-inch inside diameter pipe of material sufficient to
withstand the type of loading conditions which would occur in the
location of the junction. All junctions to underground storm drainage
shall be made at the upper 1/3 of the accepting pipe facility.
(4) To collect sump pump drainage from structures which are located on
the opposite side of a roadway from main underground storm drainage
collection, the developer shall be required to install a secondary
piping system, a minimum of 18 inches in diameter to which the minimum
four-inch discharge line(s) shall be connected. When conditions prohibit
the system to be discharged to daylight, the secondary storm drainage
shall be increased in size according to the number of sump pump connection(s)
and good design practices regarding stormwater. The secondary storm
drainage system shall be connected to the main storm drainage system
at an inlet box. The secondary collection for the sump pump discharge(s)
is recommended to be installed between the curb and the sidewalk.
The pipe material of the secondary drainage collection system for
sump pump drainage shall be corrugated plastic pipe, CPE or PVC. Cleanouts
shall be provided at one-hundred-foot intervals. The material shall
be dependent upon the location of the secondary drainage system and
the effect of loading conditions that it could be exposed to during
its use. In areas where there is no storm drainage available (i.e.,
structure not located in a subdivision or land development where drainage
is nonexistent or is located beyond the boundary lines of the subdivision
tract or land development tract, nor within any public rights-of-way
abutting the subdivision or land development tract, or impossible
to install secondary collection), alternate means of providing discharge
shall be reviewed and approved by Hatfield Township previous to final
installation.
(5) Provisions for sump pump drainage shall be incorporated in the construction
drawings of all subdivision and land development plans as:
(a)
Complete final design of the secondary storm drainage system
and junctions based upon the type of proposed houses to be constructed
and the soil conditions of the tract and the slopes of the receiving
storm sewers;
(b)
Acknowledgements on the construction plans that the secondary
drainage facilities and pump connections will be installed per the
requirements found in the field during construction and those provisions
shall be made with respect to other utilities to consider the needs
of installation for gravity fall of the secondary collection system.
(6) All conditions, requirements and provisions of this section shall
apply to the owner, agent, builder or builders involving the erection
and construction of a building on a single lot or lots or group of
lots having a basement and shall be fully complied with in all respects
in regard thereto.
B. Roof drains/downspouts.
(1) Within all subdivisions, land developments and building construction,
downspouts shall be constructed to discharge a minimum of five feet
from the building or dwelling unit. Within any multifamily or attached
dwelling unit zoning, consideration will be given for all downspouts
to be piped to the nearest drainage system; however, all efforts must
be made to discharge overall where possible.
(2) No downspouts shall discharge directly onto sidewalks and/or parking
lots. Where approved by the Township Engineer, downspouts shall discharge
underground into the proposed stormwater management system or existing
storm sewer system.