A. 
For all regulated activities, unless preparation of an SWM site plan is specifically exempted in § 210-13:
(1) 
Preparation and implementation of an approved SWM site plan is required.
(2) 
No regulated activities shall commence until the municipality issues written approval of an SWM site plan, which demonstrates compliance with the requirements of this chapter.
B. 
SWM site plans approved by Richland Township, in accordance with § 210-21, shall be on site throughout the duration of the regulated activity.
C. 
The municipality may, after consultation with DEP, approve measures for meeting the state water quality requirements other than those in this chapter, provided that they meet the minimum requirements of, and do not conflict with, state law including but not limited to the Clean Streams Law.[1]
[1]
Editor's Note: See 35 P.S. § 691.1 et seq.
D. 
For all regulated earth disturbance activities, erosion and sediment control BMPs shall be designed, implemented, operated, and maintained during the regulated earth disturbance activities (e.g., during construction) to meet the purposes and requirements of this chapter and to meet all requirements under the Pennsylvania Code Title 25 and the Clean Streams Law. Various BMPs and their design standards are listed in the Erosion and Sediment Pollution Control Program Manual (E&S Manual).[2] Commonwealth of Pennsylvania, Department of Environmental Protection, No. 363-2134-008, as amended and updated.
[2]
Editor's Note: See § 210-51B.
E. 
For all regulated activities, implementation of the volume controls in § 210-14 is required with the exception of regulated activities that meet the exemption criteria found in § 210-13A of this chapter.
F. 
Impervious areas:
(1) 
The measurement of impervious areas shall include all of the impervious areas in the total proposed development even if development is to take place in stages.
(2) 
For development taking place in stages, the entire development plan must be used in determining conformance with this chapter.
(3) 
For projects that add impervious area to a parcel, the total impervious area on the parcel is subject to the requirements of this chapter.
G. 
Stormwater flows onto adjacent property shall not be created, increased, decreased, relocated, or otherwise altered without written permission of the adjacent property owner(s). Such stormwater flows shall be subject to the requirements of this chapter.
H. 
All regulated activities shall include such measures as necessary to:
(1) 
Protect health, safety, and property;
(2) 
Meet state water quality requirements as defined in Article II;
(3) 
Meet the water quality goals of this chapter by implementing measures to:
(a) 
Minimize disturbance to floodplains, wetlands, natural slopes over 8%, and existing native vegetation.
(b) 
Preserve and maintain trees and woodlands. Maintain or extend riparian buffers and protect existing forested buffer. Provide trees and woodlands adjacent to impervious areas whenever feasible.
(c) 
Establish and maintain non-erosive flow conditions in natural flow pathways.
(d) 
Minimize soil disturbance and soil compaction. Over disturbed areas, replace topsoil to a minimum depth equal to the original depth or four inches, whichever is greater. Use tracked equipment for grading when feasible.
(e) 
Minimize thermal impacts to water of this commonwealth.
(f) 
Disconnect impervious surfaces by directing runoff to pervious areas, wherever possible.
(4) 
To the maximum extent practicable, incorporate the techniques for low-impact development practices described in "The Pennsylvania Stormwater Best Management Practices Manual" (SWM Manual).[3]
[3]
Editor's Note: See § 210-51A.
I. 
Infiltration BMPs should be spread out, made as shallow as practicable, and located to maximize use of natural on-site infiltration features while still meeting the other requirements of this chapter.
J. 
Normally dry, open top, storage facilities should completely drain both the volume control and rate control capacities over a period of time not less than 24 and not more than 72 hours from the end of the design storm.
K. 
For all regulated activities, SWM BMPs shall be designed, implemented, operated, and maintained to meet the purposes and requirements of this chapter and to meet all requirements under Pennsylvania Code Title 25, the Clean Streams Law,[4] and the Storm Water Management Act.[5]
[4]
Editor's Note: See 35 P.S. § 691.1 et seq.
[5]
Editor's Note: See 32 P.S. § 680.1 et seq.
L. 
The design storm volumes to be used in the analysis of peak rates of discharge should be obtained from the Precipitation-Frequency Atlas of the United States, Atlas 14, Volume 2, U.S. Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Weather Service, Hydrometeorological Design Studies Center, Silver Spring, Maryland, 20910. NOAA's Atlas 14[6] can be accessed at internet address: http://hdsc.nws.noaa.gov/hdsc/pfds/.
[6]
Editor's Note: See § 210-51E.
M. 
Various BMPs and their design standards are listed in the BMP Manual.[7]
[7]
Editor's Note: See § 210-51A.
N. 
The applicant may meet the rate controls criteria in § 210-15 through off-site stormwater management measures as long as the proposed measures are in the same subwatershed. Off-site stormwater control measures may only be sought if it is shown that on-site stormwater control measures cannot be physically accomplished. This does not relieve the applicant from meeting the volume controls criteria in § 210-14 on-site.
O. 
Where a development is traversed by watercourses, drainage easements shall be provided conforming to the line of such watercourses. The terms of the easement shall conform to the stream buffer requirements. If a perennial or intermittent stream passes through the site, the applicant shall create a stream buffer extending a minimum of 50 feet to either side of the top-of-bank of the channel. The buffer area shall be maintained with and encouraged to use appropriate native vegetation (Reference to Appendix H of Pennsylvania Handbook of Best Management Practices for Developing Area for plant lists). If the applicable rear or side yard setback is less than 50 feet, the buffer width may be reduced to 25% of the setback to a minimum of 10 feet. If an existing buffer is legally prescribed (i.e., deed, covenant, easement, etc.) and it exceeds the requirements of this chapter, the existing buffer shall be maintained. This does not include lakes or wetlands.
P. 
Roof drains should not be connected to streets, sanitary or storm sewers or roadside ditches to promote overland flow and infiltration/percolation of stormwater where it is advantageous to do so. When it is more advantageous to connect directly to streets or storm sewers, then it shall be permitted on a case by case basis by Richland Township.
Q. 
No regulated earth disturbance activities within Richland Township shall commence until the requirements of the Ordinance are met.
R. 
Evidence of any necessary permit(s) for regulated activities or regulated earth disturbance from DEP, Cambria County Conservation District and PA DOT must be provided.
S. 
Water shall not be stored on a roof. Water stored on parking areas and drive areas shall not exceed five inches in depth as measured from the basin bottom to the emergency spillway crest.
T. 
Storage must be open and accessible for visual inspection. Where underground detention is provide, manhole/inlet access must be provided to allow visual inspection.
U. 
Provide a four-foot-height fence around surface detention basins where two feet or more of water depth is stored measured from the pond bottom to the crest of the emergency spillway.
V. 
Where a detention basin is to be turned over to Richland Township the following apply:
(1) 
Property shall be granted to Richland Township in fee simple;
(2) 
Access shall be granted to Richland Township in fee simple;
(3) 
Access shall be a twelve-foot-wide gravel all weather roadway that is seeded with lawn vegetation on a twenty-foot-wide access area;
(4) 
Provide a six-foot-height vinyl clad chain link fence with twelve-foot-wide access gate aligned with gravel access roadway;
(5) 
Basin slopes shall have gradual slopes that are machine mowable;
(6) 
Basin shall have access ramp for mobile equipment that aligns with twelve-foot-wide access gate;
(7) 
Developer shall provide a maintenance fee as established by Richland Township by resolution to assist with future maintenance costs.
A. 
Regulated activities that create disconnected impervious areas smaller than 650 square feet are exempt from all requirements in this chapter.
B. 
Regulated activities that create disconnected impervious areas equal to or greater than 650 square feet and less than 5,000 square feet are exempt from the peak rate control and the SWM site plan preparation requirements of this chapter, but should comply with the small project requirements found in Appendix F of the ordinance.[1]
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.
C. 
Regulated activities that create disconnected impervious areas equal to or greater than 5,000 square feet and less than 10,000 square feet are exempt only from the peak rate control requirement of this chapter.
D. 
Agricultural activity is exempt from the rate control and SWM site plan preparation requirements of this chapter, provided the activities are performed according to the requirements of 25 Pa. Code Chapter 102.
E. 
Forest management and timber operations are exempt from the rate control and SWM site plan preparation requirements of this chapter, provided the activities are performed according to the requirements of 25 Pa. Code Chapter 102.
F. 
Additional exemption criteria:
(1) 
Exemption responsibilities. An exemption shall not relieve the applicant from implementing such measures as are necessary to protect public health, safety, and property.
(2) 
HQ and EV streams. An exemption shall not relieve the applicant from meeting the special requirements for watersheds draining to identified high quality (HQ) or exceptional value (EV) waters and source water protection areas (SWPA) and requirements for non-structural project design sequencing.
(3) 
Drainage problems. If a drainage problem is documented or known to exist downstream of or is expected from the proposed activity, then the municipality may require the applicant to comply with the chapter.
(4) 
Even though the developer is exempt, he is not relieved from complying with other regulations.
G. 
Exemptions from any provisions of this chapter shall not relieve the applicant from the requirements in § 210-12D through K.
H. 
The municipality may deny or revoke any exemption pursuant to this section at any time for any project that the municipality believes may pose a threat to public health and safety or the environment.
A. 
The green infrastructure and low-impact development practices provided in the BMP Manual[1] shall be utilized for all regulated activities to the maximum extent practicable.
[1]
Editor's Note: See § 210-51A.
B. 
Water volume controls shall be implemented using the design storm method in Subsection B(1) or the simplified method in Subsection B(2) below. For regulated activities that create 10,000 square feet or less of impervious cover that do not require hydrologic routing to design the stormwater facilities, this chapter establishes no preference for either methodology; therefore, the applicant may select either methodology on the basis of economic considerations, the intrinsic limitations on applicability of the analytical procedures associated with each methodology, and other factors.
(1) 
The design storm method (CG-1 in the SWM Manual[2]) is applicable to any size of regulated activity. This method requires detailed modeling based on site conditions.
(a) 
Do not increase the post-development total runoff volume for all storms equal to or less than the two-year, twenty-four-hour duration precipitation.
(b) 
For modeling purposes:
[1] 
Existing (pre-development) nonforested pervious areas must be considered meadow or its equivalent.
[2] 
Twenty percent of existing impervious area, when present, shall be considered meadow in the model for existing conditions.
[2]
Editor's Note: See § 210-51A.
(2) 
The simplified method (CG-2 in the BMP Manual[3]) provided below is independent of site conditions and should be used if the design storm method is not followed. This method is not applicable to regulated activities greater than 10,000 square feet or for projects that require design of stormwater storage facilities. For new impervious surfaces:
(a) 
Stormwater facilities shall capture at least the first two inches of runoff from all new impervious surfaces.
(b) 
At least the first one inch of runoff from new impervious surfaces shall be permanently removed from the runoff flow (i.e., it shall not be released into the surface waters of this commonwealth). Removal options include reuse, evaporation, transpiration, and infiltration.
(c) 
Wherever possible, infiltration facilities should be designed to accommodate infiltration of the entire permanently removed runoff; however, in all cases at least the first 1/2 inch of the permanently removed runoff should be infiltrated.
(d) 
This method is exempt from the requirements of § 210-15, Rate controls.
[3]
Editor’s Note: See § 210-51A.
The post-development peak discharge rates will follow the applicable approved management district or release rate map for the one-, two-, five-, ten-, twenty-five-, fifty-, and 100-year, twenty-four-hour storm events. The approved stormwater management release district maps for the Little Connemaugh River and the Stonycreek River watersheds are found in Appendix D.[1] The stormwater management subarea for the Little Conemaugh River watershed is found in Table 1. The stormwater management district criteria for the Stonycreek River watershed is found in Table 2. For any areas not shown on the release rate maps or management district maps, the post-development discharge rates shall not exceed the predevelopment discharge rates.
Table 1
Stormwater Management Districts in the Little Conemaugh River Watershed
Subarea
Subarea Release Rate Factor
B-32
1
B-33
0.7
B-34
0.7
C-6
1
C-9
1
C-10
1
Table 2
Stormwater Management Districts in the Stonycreek River Watershed
District
Proposed Condition Design Storm
(reduce to)
Existing Condition Design Storm
A
2-year
1-year
5-year
5-year
10-year
10-year
25-year
25-year
50-year
50-year
100-year
100-year
B-1
5-year
2-year
10-year
5-year
25-year
10-year
50-year
25-year
100-year
100-year
B-2
2-year
2-year
25-year
10-year
50-year
25-year
100-year
100-year
A. 
Off-site areas that drain through a proposed development site are not subject to release rate criteria when determining allowable peak runoff rates. However, on-site drainage facilities shall be designed to safely convey off-site flows through the development site.
B. 
Any stormwater management facility designed to store runoff and requiring a berm or earthen embankment shall be designed to provide a concrete lined emergency spillway to safely pass the 100-year post-development flow plus be provided with one foot of freeboard. Should any stormwater management facility require a dam safety permit under PADEP Chapter 105, design shall comply with the Chapter 105 requirements.
C. 
Any facilities that constitute water obstructions (e.g., culverts, bridges, stream enclosures, outfalls), and any work involving wetlands shall conform to PADEP Chapter 105. Design shall provide one-foot freeboard measured below the lowest point along the top of the roadway.
D. 
Drainage conveyance facilities (storm sewers and channels) not falling under PADEP Chapter 105 must be able to convey post-development runoff from a twenty-five-year design storm without surcharging the facilities.
E. 
Adequate erosion protection shall be provided along all open channels, and at all points of discharge.
F. 
Calculation methodology. Stormwater runoff from all development sites shall be calculated using either the rational method or a soil-cover-complex methodology.
(1) 
Any stormwater runoff calculations shall use generally accepted calculation technique that is based on the NRCS soil cover complex method. Table 311-1 summarizes acceptable computation methods. It is assumed that all methods will be selected by the design professional based on the individual limitations and suitability of each method for a particular site. Richland Township may allow the use of the rational method to estimate peak discharges from drainage areas that contain less than five acres. The soil complex method is required for drainage areas greater than five acres.
Table 311-1
Acceptable Computation Methodologies For Stormwater Management Plans
Method
Method Developed By
Applicability
TR-20 (or commercial computer package based on TR-20)
USDA NRCS
Applicable where use of full hydrology computer model is desirable or necessary
TR-55 (or commercial computer package based on TR-55)
USDA NRCS
Applicable for land development plans within limitations described in TR-55
HEC-1/HEC-HMS
US Army Corps of
Applicable where use of full hydrologic computer model is
PSRM
Penn State University
Applicable where use of a hydrologic computer model is
Rational method (or commercial computer package based on rational method)
Emil Kuichling (1889)
For sites less than 200 acres, or as approved by the municipality
Other methods
Varies
Other computation methodologies approved by the municipality
(2) 
All calculations consistent with this chapter using the soil cover complex method shall use the appropriate design rainfall depths for the various return period storms according to the region for which they are located as presented in Table C-1 in Appendix C of this chapter.[2] If a hydrologic computer model such as PSRM or HEC-1 is used for stormwater runoff calculations, then the duration of rainfall shall be 24 hours. The alternating block method, shown in Figure C-1, Appendix C of this chapter shall be used for the rainfall distribution.
[2]
Editor's Note: Said appendix is included as an attachment to this chapter.
(3) 
For the purposes of existing conditions flow rate determination, undeveloped land shall be considered as "meadow" in good condition, unless the natural ground cover generates a lower curve number or Rational 'C' value (i.e., forest), as listed in Table C-2 or C-3 in Appendix C of this chapter.
(4) 
All calculations using the rational method shall use rainfall intensities consistent with appropriate times-of-concentration for overland flow and return periods from the design storm curves from PA Department of Transportation Design Rainfall Curves (1986) (Figures C-2 to C-4). Times-of-concentration for overland flow shall be calculated using the methodology presented in Chapter 3 of Urban Hydrology for Small Watersheds, NRCS, TR-55 (as amended or replaced from time to time by NRCS). Times-of-concentration for channel and pipe flow shall be computed using Manning's equation.
(5) 
Runoff curve numbers (CN) for both existing and proposed conditions to be used in the soil cover complex method shall be obtained from Table C-2 in Appendix C of this chapter.
(6) 
Runoff coefficients (c) for both existing and proposed conditions for use in the rational method shall be obtained from Table C-3 in Appendix C of this chapter.
(7) 
Where uniform flow is anticipated, the Manning equation shall be used for hydraulic computations, and to determine the capacity of open channels, pipes, and storm sewers. Values for Manning's roughness coefficient (n) shall be consistent with Table C-4 in Appendix C of the chapter.
(8) 
Outlet structures for stormwater management facilities shall be designed to meet the performance standards of this chapter using any generally accepted hydraulic analysis technique or method.
(9) 
The design of any stormwater detention facilities intended to meet the performance standards of this chapter shall be verified by routing the design storm hydrograph through these facilities using the storage-indication method. For drainage areas greater than 200 acres in size, the design storm hydrograph shall be computed using a calculation method that produces a full hydrograph. Richland Township may approve the use of any generally accepted full hydrograph approximation technique that shall use a total runoff volume that is consistent with the volume from a method that produces a full hydrograph.
[1]
Editor's Note: Said appendix is included as an attachment to this chapter.