[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; 11-9-2023 by Ord. No. 2023-893]
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. 
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:
AREA OF SIGNIFICANT SLOPE
Those areas of a parcel containing slopes of 25% or greater, occupying 1,000 or more contiguous square feet.
[Amended 11-9-2023 by Ord. No. 2023-893]
AVERAGE SLOPE
The slope of a parcel as calculated by the formula set forth below.
IMPERVIOUS SURFACE
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."
SLOPE
Existing vertical grade change over horizontal grade change (known also as "rise over run"), expressed in percent.
STEEP SLOPE AREA
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.
B. 
Plan submission requirements. On all land development and subdivision plans submitted to the Township, the following items shall be shown by the applicant. This is to be provided in addition to the requirements as specified in the Upper Merion Township Code, Chapter 145, Subdivision of Land.
(1) 
The delineation of all areas on the site which have slopes greater than or equal to 15% and greater than or equal to 25%.
(2) 
Grading plans for the proposed development.
(3) 
Erosion and sedimentation control plans.
(4) 
Steep slope calculations to be shown on the plans.
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.