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In addition to the performance standards and design criteria requirements of this Part, the applicant shall comply with the following water quality requirements of this Part 2C.

A. For water quality and streambank erosion, the applicant shall design a water quality BMP to detain the proposed conditions two (2) year, twenty-four (24) hour design storm to the existing conditions one (1) year flow using the SCS Type II distribution. The applicant shall demonstrate that applicant has made provisions (such as adding a small orifice at the bottom of the outlet structure) so that the one (1) year storm takes a minimum of twenty-four (24) hours to drain from the facility from a point where the maximum volume of water from the one (1) year storm is captured (i.e., the maximum water surface elevation is achieved in the facility). At the same time, the applicant shall not attenuate the larger storms in “no detention” areas (District C) only. This can be accomplished by configuration of the outlet structure not to control the larger storms, or by a bypass or channel to divert only the two (2) year flood into the basin or divert flows in excess of the two (2) year storm away from the basin.

Where practicable, wet basins shall be utilized for water quality control and shall meet the requirements found in the Pennsylvania Stormwater BMP Manual, as revised.

Release of water can begin at the start of the storm (i.e., the invert of the water quality orifice is at the invert of the facility). The design of the facility shall consider and minimize the chances of clogging and sedimentation. Orifices smaller than three (3) inches diameter are not recommended. However, if the design professional can provide proof that the smaller orifices are protected from clogging by use of trash racks, etc., smaller orifices may be permitted.

B. In selecting the appropriate BMPs or combinations thereof, the applicant shall consider the following:

1. Total contributing area.

2. Permeability and infiltration rate of the development site soils.

3. Slope and depth to bedrock.

4. Seasonal high water table.

5. Proximity to building foundations and well heads.

6. Erodibility of soils.

7. Land availability and configuration of the topography.

8. Peak discharge and required volume control.

9. Stream bank erosion.

10. Efficiency of the BMPs to mitigate potential water quality problems.

11. The volume of runoff that will be effectively treated.

12. The nature of the pollutant being removed.

13. Maintenance requirements.

14. Creation/protection of aquatic and wildlife habitat.

15. Recreational value.

C. For areas within defined special protection subwatersheds which includes exceptional value (EV) and high quality (HQ) waters, the applicant shall maintain the temperature and quality of water and streams through the use of temperature sensitive BMPs and stormwater conveyance systems.

D. The applicant shall demonstrate that the applicant has considered and has implemented to the maximum extent feasible the guidelines found in the references specified in Appendix G for constructed wetlands, where proposed.

E. The applicant shall provide pretreatment in accordance with §§221.L and 221.M prior to infiltration.

F. Streambank restoration projects shall include the following:

1. No restoration or stabilization projects may be undertaken without examining the fluvial geomorphology of stable reaches above and below the unstable reach.

2. Restoration project design must then consider maintenance of stability in the adjacent stable reaches of the stream channel.

3. An erosion and sediment control plan approved by the Conservation District must be provided by the applicant.

4. All applicable State and Federal permits must be obtained.

G. Biology shall be incorporated into the design of all wet basins in accordance with the West Nile virus guidance found in Appendix E.

H. To accomplish the above, the applicant shall submit original and innovative designs to the Township Engineer for review and approval. Such designs may achieve the water quality objectives through a combination of BMPs (best management practices).

I. Buffers.

1. Wetlands and Vernal Ponds.

(a) Wetland identification - wetlands shall be identified in accord with the 1987 U.S. Army Corps of Engineers Manual for Identifying and Delineating Wetlands, and properly flagged and surveyed on development site to ensure they are protected.

(b) Wetlands in an artificial watercourse - wetlands contained within the banks of an artificial watercourse shall not be considered for buffer delineation purposes.

(c) Wetlands in a natural watercourse - wetlands contained within the banks of a natural watercourse, only the stream buffer shall apply.

(d) Wetland and vernal pond buffer delineation - a fifty (50) foot inner buffer and one hundred (100) foot outer buffer, measured perpendicular to and horizontally from the edge of the delineated wetland or vernal pond for a total distance of one hundred fifty (150) feet, shall be maintained for all wetlands and vernal ponds.

(1) Inner buffer - measured perpendicular to and horizontally from the edge of the delineated wetland or vernal pond, for a distance of fifty (50) feet.

a) Permitted activities/development - stormwater conveyance required by the Township, buffer maintenance and restoration, the correction of hazardous conditions, stream crossings permitted by DEP and passive unpaved stable trails shall be permitted. No other earth disturbance, grading, filling, buildings, structures, new construction, or development shall be permitted.

b) The area of the inner buffer altered by activities permitted in accord with §223(I)(1)(d)1) shall be minimized to the greatest extent practicable.

(2) Outer buffer - measured perpendicular to and horizontally from the outer edge of the inner buffer for a distance of one hundred (100) feet resulting in a total buffer of one hundred fifty (150) feet.

a) Permitted activities/development -stormwater conveyance required by the Township, buffer maintenance and restoration, the correction of hazardous conditions, stream crossings permitted by DEP, roads constructed to existing grade, unpaved trails, and limited forestry activities that do not clear cut the buffer (e.g., selective regeneration harvest) in accord with a forestry management plan shall be permitted provided no buildings are involved, and those activities permitted under §§223(I)(5) and 223(I)(6).

b) No more than twenty (20%) percent of the cumulative outer buffer on the subject parcel shall be altered by the activities permitted in accord with §223(I)(2)(d)2).

2. Lakes and Ponds.

(a) There is no outer buffer around lakes and ponds.

(b) Lake and pond buffer delineation - a fifty (50) foot buffer measured perpendicular to and horizontally from the edge of any water body, shall be maintained around any water body.

(1) Permitted activities/development - stormwater conveyance required by the Township, buffer maintenance and restoration, the correction of hazardous conditions, lake front views, boat docks and unpaved trails shall be permitted; provided no buildings are involved.

(2) The area of the buffer impacted by activities permitted in §223(I)(2)(b) shall not exceed thirty-five (35%) percent of the buffer on the parent tract.

3. Streams.

(a) Stream buffer delineation - a fifty (50) foot inner buffer and one hundred (100) foot outer buffer, measured perpendicular to and horizontally from the top-of-bank on both sides of any stream, for a total distance of one hundred fifty (150) feet, shall be maintained on both sides of any stream. See Figure 223.1.

(1) Inner buffer - measured perpendicular to and horizontally from the top-of-bank of the stream for a distance of fifty (50) feet.

a) Permitted activities/development - stormwater conveyance required by the Township, buffer maintenance and restoration, the correction of hazardous conditions, stream crossings permitted by DEP, fish hatcheries, wildlife sanctuaries and boat launch sites constructed so as not to alter the floodplain cross section, and unpaved trails shall be permitted, provided no buildings are involved. No other earth disturbance, grading, filling, buildings, structures, new construction, or development shall be permitted.

b) The area of the inner buffer altered by activities permitted in accord with §223(I)(3)(a)1) shall be minimized to the greatest extent practicable.

(2) Outer buffer - measured perpendicular to and horizontally from the outer edge of the inner buffer for a distance of one hundred (100) feet resulting in a total buffer of one hundred fifty (150) feet.

a) Permitted activities/development - stormwater conveyance required by the Township, buffer maintenance and restoration, the correction of hazardous conditions, agricultural activities, plant nurseries, parking lots constructed to existing grade, temporary fairs and carnivals, accessory uses for residential purposes, private sportsmen’s club activities, athletic facilities, orchards, wildlife sanctuaries, boat launch sites, roads constructed to existing grade, stream crossings permitted by DEP and unpaved trails and limited forestry activities that do not clear cut the buffer (e.g., selective regeneration harvest) in accord with a forestry management plan shall be permitted, provided no buildings are involved.

b) In areas of the outer buffer which are not wetlands, vernal ponds or slopes of more than fifteen (15%) percent, stormwater management facilities which improve water quality of storm- water discharge shall be permitted unless prohibited by other Township or state requirements. No other earth disturbance, grading, filling buildings, structures, new construction, or development shall be permitted.

c) No more than twenty (20%) percent of the cumulative outer buffer on the parent tract shall be altered by the activities permitted in accord with §223(I)(3)(a)2).

4. Where resource buffers overlap, the more restrictive requirements shall apply.

5. Pre-existing lots or parcels/development in outer buffers - in the case of legally pre-existing lots (approved prior to the effective date of this Part) where the useable area of a lot lies within an outer buffer area, the applicant shall obtain a waiver from the Board of Supervisors in accordance with Part 2H.

6. Improvements to existing, structures in outer buffers - the provisions of this §223(I) do not require any changes or improvements to be made to lawfully existing structures in buffers. However, when any substantial improvement to a structure is proposed which results in a horizontal expansion of that structure, the improvement may only be permitted by the granting of the waiver from the requirements of this Part. In considering a waiver application, the Board of Supervisors shall determine whether the applicant has presented evidence of hardship in addition to the standards for waivers set forth in Part 2H.

Figure 223(I). Stream Buffer

(Ord. 181, 10/11/2006, §303)