In the interest of the public health, safety and welfare, the provisions of this chapter and this article in particular are intended:

   A.   To minimize stormwater runoff, street flooding, streambank and soil erosion caused by inappropriate development of steep slope land areas and/or the conversion of undeveloped, porous surfaces to impervious ground cover.

   B.   To protect the Township from development which may cause flooding and a subsequent expenditure for public works and disaster relief affecting the economic well-being of the Township and its residents.

   C.   To protect residents from property damage and personal injury due to runoff, flooding, erosion and landslides attributable to nearby development , particularly on steeply sloping land.

   D.   To relate the intensity of development to the ability of the natural and man-made environment to support it, including the steepness of terrain, in order to minimize grading, the removal of vegetation, the construction of nonabsorbent surfaces, runoff and erosion and to help ensure the utilization of land in accordance with its natural capabilities to support development .

   E.   To restrict the impact of erosion and sedimentation and the alteration of natural drainage patterns which may aggravate flooding both in the immediate area and in downstream areas.

   F.   To maximize groundwater recharge and maintain the base flow of streams and watercourses , thereby ensuring both the quantity and quality of groundwater and surface waters.

   G.   Improve surface water quality by reducing the amount of nutrients, sediment, organic matter, pesticides, and other harmful substances that reach watercourses , wetlands, subsurface, and surface water bodies by using scientifically proven processes including filtration, deposition, absorption, adsorption, plant uptake, and denitrification, and by improving infiltration, encouraging sheet flow, and stabilizing concentrated flows.

   H.   Improve and maintain the safety, reliability, and adequacy of the water supply for domestic, agricultural, commercial, industrial, and recreational uses along with sustaining diverse populations of aquatic flora and fauna.

   I.   Preserve and protect areas that intercept surface water runoff, wastewater, subsurface flow, and/or deep groundwater flows from upland sources and function to remove or buffer the effects of associated nutrients, sediment, organic matter, pesticides, or other pollutants prior to entry into surface waters, as well as provide wildlife habitat, moderate water temperature in surface waters, attenuate flood flow, and provide opportunities for passive recreation

   J.   Work with floodplain , steep slope , and other requirements that regulate environmentally sensitive areas to minimize hazards to life, property, and riparian features.

   K.   Recognize that natural features contribute to the welfare and quality of life of the Township residents.

   L.   Conserve natural, scenic, and recreation areas within and adjacent to riparian areas for the community's benefit.

   A.   The limitations of this chapter pertaining to impervious surfaces shall be strictly adhered to except as set forth herein.

      (1)   (Reserved). [Amended 9-11-2012 by Ord. No. 12-1259]

      (3)   A lot which has a minimum net lot area of 25 acres or more, is in a residential zoning district, is used for a public school purpose and contains an elementary, middle and/or high schoolbuilding (s), may exceed the impervious surface limitations set forth in this chapter, by no more than 20% of the lot area provided the following standards are met:

         (a)   For applications proposing improvements that result in up to 10% more impervious surfaces on the development site than what is currently permitted in the underlying zoning district, (i.e., the 25% limit is increased to up to 35%) stormwater management facilities shall be designed to release no more than 90% of the pre-development rate of run off for all regulated storm events, (i.e., the 1, 2, 10, 25, 50, 100 flood event.)

         (b)   For applications proposing improvements that result in between 10% and 20% more impervious surfaces on the development site than what is currently permitted in the underlying zoning district, (i.e., the 25% limit is increased to between 35% and 45%) stormwater management facilities shall be designed to release no more than 75% of the predevelopment rate of run off for all regulated storm events, (i.e., the 1, 2, 10, 25, 50, 100 flood event.)

   B.   Common driveways; impervious surface allocation. For the purpose of determining the amount of impervious surface on a lot served by a common driveway, the total impervious surface of that common driveway shall be allocated evenly among the lots served, unless it is otherwise allocated in a recorded covenant approved by the Township and binding on the properties affected, in which case such recorded allocation shall control.

   C.   Where no impervious surface limitations are imposed within an overlay district, such limitations shall be the same as those applicable in the underlying district.

   A.   Technical terminology used in this article shall be interpreted to the meanings used by recognized sources and experts in the fields of forestry, wood land or meadow management, streambank protection, wetlands management, erosion and sedimentation control, or other relevant fields.

   B.   No land disturbance shall be permitted within any riparian corridor except as permitted below:

      (1)   Open space uses such as wildlife sanctuaries, nature preserves, forest preserves, fishing areas, passive areas for public or private parklands, and reforestation.

      (2)   Customary agricultural practices in accordance with a soil conservation plan approved by the Montgomery County Conservation District and a nutrient management plan in accordance with state requirements, if applicable.

      (3)   Regulated activities permitted by the Pennsylvania Department of Environmental Protection and the Township for stream or wetland crossing or other encroachment (i.e., farm vehicle and livestock, recreational trails, roads, and driveways sewer or waterlines, and utility transmission lines), provided that any disturbance is offset by riparian corridor improvements as approved by the Township.

      (4)   Vegetation management in accordance with a stream bank stabilization plan or an approved landscape or open space management plan.

      (5)   Naturalized stormwater management facilities, provided the entire facility is located a minimum of 50 feet from the defined top of bank, high water mark, or wetland limit, and situated outside the 100-year floodplain .

      (6)   The following passive and active recreational areas, provided they are designed in a manner that they will not permit concentrated flow of stormwater runoff:

         (a)   Camps.

         (b)   Campgrounds.

         (c)   Picnic areas.

         (d)   Golf courses.

         (e)   Ballfields.

         (f)   Playgrounds and courts.

         (g)   Trails and paths.

   C.   Prohibited uses. Any use or activity not authorized under Subsection A. above shall be prohibited within the riparian corridor . The following activities and facilities are specifically prohibited:

      (1)   Clear-cutting of trees and other vegetation.

      (2)   Selective cutting of trees and/or the clearing of other vegetation, except where such clearing is necessary to prepare land for a use permitted under Subsection A. above or where removal is necessary as a means to eliminate dead, diseased or hazardous trees. Removal is subject to revegetation by native plants that are most suited to the riparian corridor .

      (3)   Storage of any hazardous or noxious materials.

      (4)   Use of fertilizers, pesticides, herbicides, and/or other chemicals in excess of prescribed industry standards or the recommendations of the Montgomery County Conservation District and the Township.

      (5)   Roads or driveways, except as permitted as corridor crossings by the Pennsylvania Department of Environmental Protection and the Township under § 255-33.B.(3).

      (6)   Parking lots.

      (7)   Any type of permanent structure, including fences, with the exception of split-rail fences.

      (8)   Subsurface sewage disposal areas.

      (9)   Sod farming

      (10)   Stormwater basins, including berms and outfall facilities.

   D.   Nonconforming buildings, structures, and uses shall be regulated under the provisions of Article XX - Nonconforming Uses.

   E.   Vegetation of riparian area. In cases where a subdivision and/or land development is proposed, planting or replanting of the riparian corridor shall be required where there is little or no existing streamside vegetation. Native vegetation approved by the Township must be used in replanting efforts. Three layers of vegetation are required when replanting the riparian corridor . These layers include herbaceous plants that serve as ground cover, understory shrubs, and trees that form an overhead canopy. The vegetation plan shall be prepared by a qualified professional such as a landscape architect or engineer and shall comply with the following minimum requirements:

      (1)   Ground cover . Ground cover consisting of a native seed mix extending a minimum of 25 feet in width from the edge of the stream bank must be provided along the portion(s) of the stream corridor where little or no riparian vegetation exists. Appropriate ground cover includes native herbs and forbs, exclusive of noxious weeds or invasive plants as defined by the Pennsylvania Department of Agriculture. This twenty-five-foot-wide planted area shall be designated on the plan as a no mow zone and shall be left as natural cover except in accordance with the maintenance instructions stated on the plan.

      (2)   Trees and shrubs. These planting layers include trees that form an overhead canopy and understory shrubs. Overstory trees are deciduous or evergreen trees that include oak, hickory, maple gum, beech, sycamore, hemlock, pine and fir. Evergreen and deciduous shrubs should consist of elderberry, viburnum, azalea, rhododendron, holly, laurel and alders. These plants shall be planted in an informal manner and at a rate of at least one overstory tree and three shrubs for every 20 linear feet of stream or waterway.

      (3)   Exceptions. These planting requirements shall not apply to existing farm fields located within the riparian buffer if farming operations are to be continued and the required nutrient management plan is met.

The following regulations shall apply on all land having a slope of 10% or more as delineated on a plan which meets the requirements of a preliminary plan as specified in Chapter 212, Subdivision and Land Development:

   A.   Every lot hereafter created by subdivision having an average slope of at least 10%, but not more than 15%, shall have the minimum lot area increased by a factor of 1.3 and shall not have impervious surfaces exceeding 30% of the lot area as increased.

   B.   Every lot hereafter created by subdivision having an average slope of at least 15%, but not more than 25%, shall have the minimum lot area increased by a factor of 1.5 and shall not have impervious surfaces exceeding 20% of the lot area as increased.

   C.   Every lot hereafter created by subdivision having an average slope of at least 25% shall have the minimum lot area increased by a factor of two and shall not have impervious surfaces exceeding 10% of the lot area as increased.

   D.   All freestanding structures , buildings and substantial improvements (with the exception of driveways and utilities when no other location is feasible) are prohibited on slopes of 35% or greater 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, copies of which are on file in the office of the Township Manager, Upper Dublin Township Building, 801 Loch Alsh Avenue, Fort Washington, Pennsylvania.

Neither the approval of any proposed subdivision by any officer, employee or agency of the Township of Upper Dublin nor the grant of any subdivision approval by the Board of Commissioners of the Township of Upper Dublin shall constitute a representation, guaranty or warranty of any kind by the Township of Upper Dublin 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 of Upper Dublin or its officers, employees, agencies or members of its agencies.