[Added 10-16-1989 by Ord. No. 89-564; amended 8-13-1998 by Ord. No. 98-672]
The intent of the Township is permitting development
pursuant to this article is as follows:
A.
To prevent inappropriate development of steep slope
areas by seeking to maintain existing vegetation and stable soil coverage
on steep slopes.
B.
To minimize the grading and removal of vegetation
to ensure the utilization of land in accordance with its natural capabilities
to support development.
C.
To prevent development that would cause excessive
erosion and subsequent increase in flood hazards within the Township.
D.
To promote the preservation of natural features of
the land which are necessary to maintain the ecological balance of
the environment.
E.
To promote the use of engineering and design practices
to provide the maximum in safety and human enjoyment while adopting
development to, and taking advantage of, the best use of the natural
terrain.
[Amended 12-14-2006 by Ord. No. 2006-759]
The intent of this article is to promote the preservation of natural features, maintain the ecological balance of the environment, and protect property and life from dangers presented by steep slopes. The requirements of all zoning districts shall be modified in accordance with the provisions of this article on all land having a slope of 15% or more as delineated on a plan which meets the requirements of a preliminary or final plan as specified in Chapter 145, except for land that qualifies as exempt below. In order to be exempt from the provisions of Article XXXIIA herein, the applicant must provide by credible evidence to the Board of Supervisors at the time of conditional use, subdivision or land development approval that the steep slope in question meets the following conditions. In any case, grading plans and erosion and sedimentation control plans shall still be prepared and submitted to the Township for their approval at the appropriate time.
A.
The slope was created in connection with a previous
alteration to the grades of the property and is not naturally occurring
and was man-made after 1940.
B.
A change in the slope will not present an added risk
of flooding, collapse, erosion, or other danger to the existing or
future inhabitants or structures on the property or any other properties,
roads, or public services.
For the purpose of this article, the following
definitions shall apply:
Those areas of a parcel containing naturally occurring slopes
of 25% or greater, occupying 1,000 or more contiguous square feet.
The slope of a parcel as calculated by the formula set forth
below.
Surfaces that do not absorb water, including but not limited
to all buildings, parking areas, driveways, roads, sidewalks and areas
of concrete and nonporous asphalt or other areas determined by the
Township Engineer to be an "impervious surface."
Existing vertical grade change over horizontal grade change
(known also as "rise over run"), expressed in percent.
That area delineated on a lot having slopes greater than
or equal to 15%.
In every zoning district, the following regulations
shall apply:
A.
Every lot hereafter created by subdivision or presently
undeveloped having an average slope greater than or equal to 15% shall
have a minimum lot area, as defined by the underlying zoning district,
increased by a factor of 1.5 and shall not have impervious surfaces
exceeding 20% of the lot area or 50% of the maximum permitted impervious
coverage permitted in the underlying district, whichever is greater.
B.
All freestanding structures, buildings and substantial
improvements (with the exception of driveways and utilities when no
other location is feasible) are prohibited in areas of significant
slope and are prohibited on slopes where the soil type is classified
as "stony land, steep" by that document entitled "Soil Survey Montgomery
County, Pennsylvania," prepared by the United States Department of
Agriculture. Soil Conservation Service, dated April, 1967, and subsequent
updates and revisions thereof.
C.
Each disturbance, including regrading, filling, clearing,
driveways and utilities is limited to a total of 20% of all areas
of significant slope on a parcel or tract and only when the Township
Engineer determines that no other location is feasible.
D.
Earth disturbance for purposes of regrading, filling,
clearing, driveways and utilities is limited to a total of 30% of
all areas of steep slope on a parcel or tract and only when the Township
Engineer determines that no other location is feasible.
E.
On all lots or parcels containing steep slopes, it
shall be prohibited to fill areas adjacent to steep slope areas or
areas of significant slope when such filing is intended to eliminate
the areas of slope or the areas of significant slope.
[Amended 12-14-2006 by Ord. No. 2006-759]
Slopes greater than or equal to 15% shall be
determined from measurements by registered professional engineers,
surveyors or landscape architects using accepted engineering practices.
Such slopes may also be determined as delineated on maps made part
of the Soil Survey of Montgomery County, Pennsylvania; provided, however,
that in the event of a conflict between prepared measurements and
the soil survey maps the measurements shall control. All determinations
concerning the existence or nonexistence of steep slope areas shall
be made by the Township Engineer. The representative sample of a steep
slope or significant slope shall be based on a cumulative change in
grade of six feet or more. Therefore, all steep and significant slope
areas shall be shown, but only those occurring over three consecutive
two-foot contour intervals will invoke the use restrictions herein.
A.
Average slope shall be calculated by the formula:
|
S
|
=
|
0.0023 x l x L
| |
|---|---|---|---|
|
A
|
|
Where
| ||||
|---|---|---|---|---|
|
S
|
=
|
Average slope in percent.
| ||
|
l
|
=
|
Contour interval expressed in feet.
| ||
|
L
|
=
|
Combined length of all contour lines through
lot expressed in feet.
| ||
|
A
|
=
|
Lot area in acres.
| ||
Neither the approval of any proposed subdivision
or development plan by Upper Merion Township shall constitute a representation,
guaranty or warranty of any kind by Upper Merion Township or by any
of its officers, employees, agencies or members of its agencies of
the safety or practicality of the proposed subdivision and use, and
such approval or grant of approval shall create no liability on the
part of the Township, its officials or employees.
