§ 395-38. Storm and surface drainage.

A. 

Goal. It is the goal of Walnutport Borough to protect the health, safety and general welfare of Walnutport Borough residents by protecting the surface waters and groundwaters of the Borough through effective stormwater management and control of sedimentation and erosion, as provided in this section. Through effective stormwater management, negative impacts of inadequately managed land development can be minimized, including:

(1) 

Altered hydrology, including increased flooding and flood-related damage to general health and property.

(2) 

Lowering of the groundwater table.

(3) 

Physical stream impacts, including altered stream temperature.

(4) 

Aquatic biological impacts.

(5) 

Addition of nonpoint source pollutants to both surface and groundwaters.

B. 

Purpose. The purpose of comprehensive stormwater management in Walnutport Borough is to:

(1) 

Minimize both quantitative and qualitative stormwater impacts resulting from new land development, which would adversely affect the health, safety and welfare of all aspects of life in the Borough.

(2) 

Prevent significant increase in surface runoff volumes, predevelopment to postdevelopment, which would cause worsened flooding downstream in the watershed, erode stream banks, create other flood-related health-welfare-property losses and work to reduce runoff volumes to natural levels.

(3) 

Maintain the predevelopment water balance in watersheds and subwatersheds and work to restore natural hydrologic regimes wherever possible throughout the stream system.

(4) 

Maintain the predevelopment volume of groundwater recharge.

(5) 

Maintain predevelopment peak rates of discharge, site-by site, so as not to worsen flooding at adjacent downstream sites, and to work to restore peak runoff rates to natural levels.

(6) 

Minimize alteration of natural predevelopment drainage patterns into and out of basins and subbasins.

(7) 

Minimize nonpoint source pollutant loadings to ground and surface waters generally throughout Walnutport Borough.

(8) 

Minimize impacts on stream temperatures.

(9) 

Minimize aesthetic impacts.

(10) 

Minimize sinkhole potential.

(11) 

Maximize use of nonstructural stormwater management approaches, especially those which rely on natural processes, where appropriate.

C. 

Authority. Walnutport Borough is empowered to regulate new land development activities that affect stormwater runoff by the authority of the Pennsylvania Municipalities Planning Code, Act 247 of 1968, as amended by Act 170 of 1988, as further amended by Act 209 of 1990 and Act 131 of 1992, 53 P.S. § 10101. Stormwater management is also enabled by Pennsylvania's Stormwater Management Act of 1978 (Act 167), as well as the Pennsylvania Environmental Amendment.

Editor's Note: See 32 P.S. § 680.1 et seq.

D. 

Applicability. These regulations apply to:

(1) 

All activities governed by this chapter.

(2) 

Construction of separate or additional impervious surfaces (driveways, parking lots, additions to buildings, etc.) exceeding 1,000 square feet.

(3) 

Outdoor storage, including storage of material (rock, soil, etc.) where ground contact exceeds 4,000 square feet or where material is placed either on slopes exceeding 8% floodplains, or in drainageways.

(4) 

Any other activities with adverse stormwater impacts which, in the opinion of the Borough, should be governed by these regulations.

(5) 

The management of stormwater on the site, both during and upon completion of the disturbances associated with the proposed subdivision or land development, shall be accomplished in accordance with the standards and criteria of this section. The design of any temporary or permanent facilities and structures and the utilization of any natural drainage systems shall be in full compliance with these terms and the interpretations of the Borough.

(6) 

At the time of application for a building permit for any approved lot created by a subdivision under terms of this section, issuance of the permit shall be considered to be conditioned upon adherence to the terms of this section.

E. 

Standards for stormwater management. All activities as listed in this section as specified above shall comply with provisions of this section:

(1) 

Permanent stormwater management standards.

(a) 

Standard 1.

[1] 

After installation of impervious cover, there shall be no increase in the volume of stormwater runoff being discharged from the site for up to the two-year frequency rainfall, predevelopment to postdevelopment, calculated using a methodology as described in this section.

[2] 

Applicants may request a partial waiver, where a portion of the Standard 1 volume requirement is set aside (i.e., volume control is achieved for a lesser storm such as the one-year storm or six-month storm). Or applicants may request a total waiver, where the entire Standard 1 volume requirement is set aside. The need for waivers of any type must be based on demonstration by the applicant that due to the existing soil, bedrock, water table or other natural conditions and limitations at the site, the Standard 1 volume requirement cannot be satisfied through use of reasonable best management practices, as defined in this section.

(b) 

Standard 2.

[1] 

After installation of impervious cover and assuming compliance with Standard 1 volume provisions (assuming no waiver), the peak rate of stormwater discharge from the site for all design storms up to and including a one-hundred-year design storm shall not exceed the peak rate of stormwater discharge from the site of the same storms before disturbance. Design storms include:

[a] 

Two- year.

[b] 

Ten-year.

[c] 

Twenty-five-year.

[d] 

Fifty-year.

[e] 

One-hundred-year.

[2] 

If a partial waiver has been issued but at least 50% of the two-year frequency rainfall volume requirement specified under Standard 1 is being met, these Standard 2 provisions also apply.

(c) 

Standard 3. In those cases where a total waiver from the Standard 1 volume requirement is issued or where a partial waiver is issued and less than 50% of the volume requirement specified under Standard 1 is being met, then the peak rate standards set forth under Standard 2 above are further modified, so that the postdevelopment peak-rate discharges from the site for two year storms and larger, up to the ten-year storm, must be equal to or less than the predevelopment peak rate of discharge for the two-year storm.

(d) 

Standard 4.

[1] 

Significant loadings of nonpoint source pollutants shall not be discharged into either surface or groundwater. If the total volume and peak rate standards above are met as in Standards 1 and 2 (including if a partial waiver for volume control is approved by the Borough, but at least 50% of the volume requirement specified in Standard 1 is met), then water quality impacts are assumed to be adequately controlled.

[2] 

If the requirements set forth in Standards 1 and 2 above cannot be achieved and a total waiver is issued or a partial waiver is issued where less than 50% of the volume requirement specified under Standard 1 is being met, then an additional water quality requirement must be met in order to guarantee that significant water quality impacts will not result from the proposed development action. A water-quality-oriented best management practice (BMP) designed to capture and treat stormwater generated for up to the one inch rainfall event must be employed. These BMPs include, but are not limited to:

[a] 

Constructed wetlands/wetland forebays.

[b] 

Retention ponds/extended detention ponds.

[c] 

Filters (sand-peat, underground sand, perimeter sand filter, organic sand, pocket sand filter, gravel).

[d] 

Grass channels.

[e] 

Dry swales.

[f] 

Wet swales.

[g] 

Other bioretention BMPs.

[h] 

Filter strips.

[3] 

BMP selection, design and implementation shall be based upon appropriate reference materials such as the Pennsylvania Handbook of Best Management Practices for Developing Areas, Design of Stormwater Filtering Systems and other manuals.

(e) 

Standard 5. Under special conditions, the Borough may impose the following additional restrictions on stormwater discharges:

[1] 

Peak discharge may be further restricted when the Borough believes that a probable risk to downstream structures or unique natural areas exists or that existing severe flooding problems could be further aggravated.

[2] 

Measures may be imposed to protect against ground or surface water pollution from significant pollutant-producing sources (so called "hotspots" such as industrial uses, gas stations, fast food and other commercial uses generating large numbers of vehicle trips and other uses at the determination of the Borough) and where the nature of the soils or bedrock underlying a stormwater management structure constitutes substantial risk of contamination, such as limestone formations. Special provisions which act to remove pollutant loadings (such as filtration devices like sand peat filters, multiple chamber catch basins and inlets, oil separators and others) may be required by the Borough.

[3] 

Where groundwater yields are very low or where a groundwater supply already is heavily used or where maintenance of downstream wetlands is of special concern, the Borough may require that the entire volume of the two-year storm postdevelopment be retained and infiltrated.

(2) 

Stormwater management calculation methods.

(a) 

The Soil Cover Complex (SCC) Method. The United States Department of Agriculture, Natural Resources Conservation Service (NRCS, formerly the Soil Conservation Service) Technical Release No. 55 (Second Edition, June 1986, or latest edition; hereafter referred to as "TR-55") Tabular Method Hydrograph is the preferred method for detention modeling. A variety of software packages are available which incorporate this method. The NRCS TR-20 and Penn State Runoff Model (PSRM) are also acceptable SCC models. Note that use of TR-55 with many of the natural system-based approaches and practices recommended by this section often requires that sites be subdivided into multiple subareas as necessary for TR-55 modeling.

[1] 

The rainfall values that apply for TR-55 calculations are as follows:

[a] 

Two year, twenty-four-hour storm of 3.00 inches of rainfall.

[b] 

Ten year, twenty-four-hour storm of 4.56 inches of rainfall.

[c] 

Twenty-five year, twenty-four-hour storm of 5.52 inches of rainfall.

[d] 

Fifty year, twenty-four-hour storm of 6.48 inches of rainfall.

[e] 

One-hundred-year, twenty-four-hour storm of 7.44 inches of rainfall.

[2] 

A Type H distribution storm shall be assumed.

[3] 

Runoff curve number (RCN) values shall be taken from TR-55 Tables 2-2a and 2-2b. Hydrologic Soil Group (HSG) information is provided in TR-55 Exhibit A-1.

[4] 

The following equation shall be applied to the two-year storm pre- and postdevelopment runoff volumes. The difference between the two volumes is the volume to be controlled under Stormwater Management Standard 1. Software routines for calculating basin volume typically provide a lower than actual volume difference and should not be used for this purpose.

	Vr = 53.33Q(Am)
	Where:
		Vr	=	Runoff volume (acre-feet)
		Q	=	Runoff (inches)
		Am	=	Drainage area (mi)
		53.33	=	conversion factor from in-mi to acre-feet

(b) 

The Rational Method. The Rational Method is the preferred method for storm sewer and swale design calculations. For stormwater detention or volume calculations, the Universal Rational Method, which generates a hydrograph similar to the TR-55 hydrograph, must be used. An example of a computer program that develops an appropriate hydrograph is the Penn State Urban Hydrology Model (PSUHM) or Virginia Tech's updated version of this model (VTPSUHM). Use of the Rational Method for sizing peak-rate control detention facilities is restricted to drainage areas where surfaces are relatively uniform in nature and whose size is less than 5,000 square feet.

[1] 

Rainfall intensities shall be based upon the current Pennsylvania Department of Transportation Storm Intensity-Duration-Frequency Chart appropriate for the project area.

[2] 

The following runoff coefficients shall be used (see table below).

[3] 

The rational hydrograph method (RATHYD) contained within PSUHM and VT-PSUHM has a volume-estimating routine based on a double-parabolic-shaped outflow hydrograph. This routine can be manipulated to provide a calculation suitable for determining the two-year storm volume increase as required by Standard 1. The following is summarized from the RATHYD program help text: The parabolic outflow hydrograph is a concave up parabola from zero minutes to the time to peak (Tc) and concave down from the time to peak to the point of intersection with the inflow hydrograph, at which point the outflow also reaches its maximum rate. The program computes the area between the inflow and outflow curves at intervals equal to Tc. The outflow must be greater than the last inflow hydrograph ordinate; otherwise, the outflow hydrograph will never intersect the inflow hydrograph (an answer of unknown accuracy would be computed). See Appendix V.

Editor's Note: Appendix V is included at the end of this chapter.

[4] 

The application of this routine to the volume requirement calculation shall be done as follows: Calculate an estimate of the hydrograph volume by selecting an outflow value that is 0.1 cfs larger than the last ordinate of the inflow hydrograph. Calculate this separately with both the two-year storm pre- and postdevelopment hydrographs, and then calculate the algebraic difference to compute the volume required to satisfy Standard 1.

(c) 

Other methods may be used with prior approval from the Borough.

(d) 

Predevelopment conditions shall be calculated using the following assumptions:

[1] 

Woodland shall be used as the prior condition for those portions of the site having wooded areas containing trees greater than six inches caliper DBH or where such trees existed within three years of application.

[2] 

Meadow shall be used for all other areas including areas of existing cultivation or impervious surface.

[3] 

Average antecedent moisture condition.

(e) 

Time of concentration calculations shall be submitted based upon current design methods outlined in TR-55. The sheet flow and shallow concentrated flow lengths used in the calculations shall be justified based on existing or proposed topography. The time of concentration flow paths (pre- and postdevelopment) shall be shown on the grading plan, and shall be representative of the drainage area. Overland flow (sheet flow) shall be calculated using the modified kinematic wave travel time equation from TR-55. The minimum predevelopment sheet flow length shall be assumed to be 150 feet, unless a shorter length can be justified. The maximum postdevelopment sheet flow length for unpaved surfaces shall be 100 feet for most situations (150 feet for areas that will remain undisturbed). Use of maximum flow lengths shall be justified, with all flow lengths subject to approval by the Borough. Designs involving the Rational Method are especially sensitive to overland flow time using this equation. Therefore, the maximum length of sheet flow for use in rational method calculations shall not exceed 50 feet.

(f) 

Special provisions for basins.

[1] 

Where basins are used, postdevelopment runoff hydrographs shall be routed through the proposed detention or retention basins using storage-indication procedures. The peak rate of runoff resulting from the summation of the basin discharge hydrograph(s) and the bypass hydrograph (or summation of peaks) shall not exceed the peak predevelopment rate of discharge. Note: Rational Method hydrographs of different Tc's shall not be added.

[2] 

Where applicable, postdevelopment time of concentration to a detention or retention basin shall be the time of concentration in the storm sewer system to its point of discharge into the basin. Overland flow from this discharge point to the outlet structure shall not be included in the time of concentration.

[3] 

When designing regional detention or retention basins for office parks, industrial parks, etc., the following design criteria shall be followed:

[a] 

Assumed impervious, lawn, etc., coverage areas shall be noted in the calculations for each proposed lot which will drain to the basin. Impervious coverage shall be assumed to be the maximum coverage allowed by Chapter 450, Zoning.

[b] 

A six-minute time of concentration shall be used to calculate the postdevelopment basin inflow hydrographs (five minutes for Rational Method). If a significant portion of the contributing drainage area will remain undeveloped, the inflow hydrograph may be derived by adding the undeveloped area hydrograph to the developed area hydrograph (based on a six-minute time of concentration).

[c] 

For lots which will have on-lot detention or retention basins, the following criteria shall also apply:

[i] 

The predevelopment time of concentration for the lot shall be the same as the predevelopment time of concentration for the entire predevelopment drainage area in which it is located.

[ii] 

The required predevelopment time of concentration and NRCS runoff curve number for each lot shall be noted on the recorded plan.

(3) 

Stormwater management standards during land disturbance. The Borough reserves the right to require installation of appropriate construction phase staging areas for construction and related vehicle parking in order to prevent sedimentation and erosion problems resulting from vehicle movements onto and off of the site. Different techniques including paved staging areas and sediment removal devices may be required, depending upon the development site and its impacts.

(4) 

The Riparian Buffer Area (RBA). Areas immediately adjacent to the Borough's perennial streams and waterways as mapped on U.S. Geological Survey 1:24,000 scale quadrangle maps are defined as the Riparian Buffer Area (RBA). In the RBA, special requirements as set forth in this section apply in order to maintain important natural functions. These RBA requirements are based on both the heightened sensitivity of the RBA zone and the potential to negatively impact the stream system when this RBA zone is disturbed, as well as the potential of this RBA zone to mitigate to the maximum extent the negative effects of development in areas adjacent to the stream system. The RBA includes three subzones, Zones 1 through 3, extending landward from the top of the streambank where different requirements are imposed:

(a) 

Zone 1, a minimum twenty-five-foot setback zone, plus wetlands, measured from the top of the bank of the water body, as reviewed and approved by the Borough, where no disturbance of vegetation and soil except for restoration and or reforestation shall occur, in order to shade the stream with natural vegetation, to provide a source of numerous other organic inputs to the aquatic system, to anchor the streambank and floodplain area and to consume and otherwise remove nitrogen, sediment and other substances which can adversely affect stream systems. Where prohibitive slopes (25+%) are located within 35 feet of a watercourse, Zone 1 shall extend the entire distance of this sloped area.

(b) 

Zone 2, a one-hundred-foot managed buffer zone, extending outward from Zone 1 (for a total of 125 feet), where disturbance of natural vegetative cover shall be limited to selective logging, not to exceed 25%, and other activities which minimally disrupt existing tree cover and soil mantle, in order to maximize filtering and overall physical removal of particulate-form pollutants from runoff generated upgradient and to promote subsurface vegetative uptake of nitrogen and other non-particulate elements from stormwater generated upgradient.

[1] 

In cases where Zone 1 extends beyond 25 feet due to the presence of prohibitive slopes, the width of Zone 2 shall be adjusted so that the full riparian buffer equals a total width of 125 feet.

[2] 

Where the Zone 2 riparian buffer is not wooded, it shall be maintained as a filter strip of dense grass and forbs or other features to provide sediment filtering, nutrient uptake, and convert concentrated flow to uniform, shallow, sheet flow. When a subdivision or land development is proposed where there is no established vegetated or wooded buffer (such as in areas previously cultivated for agriculture) a one-hundred-twenty-foot riparian buffer shall be established and maintained in accordance with the following guidelines:

[a] 

Forested and unforested vegetation shall be established through natural succession. Selective planting shall be incorporated on sites devoid of vegetation to stimulate native species and discourage invasive species.

[b] 

Plant selection and planting shall be consistent with Northampton County Conservation District, PADEP or USDA riparian forested buffer guidance.

[3] 

Zone 3, a zone of varying width extending outward from Zone 2. Zone 3 is defined in those cases where upslope areas adjacent to the RBA are being disturbed during the land development process and where direct discharge of stormwater would otherwise occur. Zone 3 is intended to include level spreading or similar devices as necessary to ensure that any direct discharge flows are properly distributed as sheet flow and channelization and point source discharges are avoided. Zone 3 shall include a minimum twenty-five-foot setback from impervious surfaces.

[4] 

The RBA may be included in net density calculations with uses permitted in Chapter 450, Zoning, of the Code of the Borough of Walnutport, unless this RBA is required to be subtracted out as the result of other applicable regulations in Chapter 450, Zoning, such as regulation of the floodplain.

[5] 

An RBA adjacent to "high quality waters" and "exceptional value waters" designated under the Pennsylvania Department of Environmental Protection, Chapter 93, Rules and Regulations, shall be subject to the provisions of the Pennsylvania Department of Environmental Protection, Special Protection Waters Implementation Handbook, and its amendments.

(5) 

Riparian buffer zones shall be restricted to the following uses:

(a) 

Zone 1 (very restricted). Flood control, utility rights-of-way, pervious footpaths.

(b) 

Zone 2 (restricted). Pervious, passive recreational uses, natural stormwater BMPs, pervious bike paths, tree removal by permit.

(c) 

Zone 3 (limited restrictions). Residential uses, including lawn, sheds (or similar structures) less than 150 square feet, garden, compost, yard wastes, nonstructural stormwater BMPs.

(6) 

Riparian buffers shall be preserved or restored with native vegetation that can be maintained through the delineation, plan review, construction, and occupancy stages of development.

(7) 

The applicant shall submit designs for water quality facilities to the Borough Engineer for review and approval. Such designs may achieve the water quality objectives through a combination of BMPs. The design and selection of water quality facilities shall follow the Maryland Stormwater Design Manual, Maryland Department of the Environment (http://www.mde.state.md.us/programs/Water/StormwaterManagementProgram/ MarylandStormwaterDesignManual/Pages/), latest ed. or other design manuals approved by the Borough.

(8) 

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

(a) 

Total contributing area.

(b) 

Permeability and infiltration rate of the site soils.

(c) 

Slope and depth to bedrock.

(d) 

Seasonal high water table.

(e) 

Proximity to building foundations and wellheads.

(f) 

Erodibility of soils.

(g) 

Land availability and configuration of the topography.

(h) 

Consistency with approved watershed and stormwater management plans or regulations.

(i) 

Impact on neighboring and downstream properties and facilities.

(9) 

The following additional factors should be considered when evaluating the suitability of BMPs used to control water quality at a given development site:

(a) 

Peak discharge and required volume control.

(b) 

Streambank erosion.

(c) 

Efficiency of the BMPs to mitigate potential water quality problems.

(d) 

The volume of runoff that will be effectively treated.

(e) 

The nature of the pollutant being removed.

(f) 

Maintenance requirements.

(g) 

Creation/protection of aquatic and wildlife habitat.

(h) 

Recreational value.

(i) 

Enhancement of aesthetic and property value.

(j) 

Impact on neighboring and downstream properties and facilities.

(10) 

Any stormwater management facility (i.e., detention basin) designed to store runoff and requiring a berm or earthen embankment required or regulated by this chapter shall be designed to provide an emergency spillway to handle flow up to and including the one-hundred-year postdevelopment conditions. The height of the embankment must be set so as to provide a minimum one foot of freeboard above the maximum pool elevation computed when the facility functions for the one-hundred-year postdevelopment inflow. Should any stormwater management facility require a dam safety permit under PADEP Chapter 105, the facility shall be designed in accordance with Chapter 105 and meet the regulations of Chapter 105 concerning dam safety which may be required to pass storms larger than the one-hundred-year event. Any inspections of this dam required by any regulatory agency shall be prepared by competent consultants and at the cost of the maintainer of the facility.

(11) 

Any facilities that constitute water obstructions (e.g., culverts, bridges, outfalls, or stream enclosures) and any work involving wetlands as directed in PADEP Chapter 105 regulations (as amended or replaced from time to time by PADEP) shall be designed in accordance with Chapter 105 and will require a permit from PADEP. Any other drainage conveyance facility that does not fall under Chapter 105 regulations shall be designed to convey, without damage to the drainage structure or roadway, runoff from a minimum twenty-five-year design storm. The Borough may require design based on a larger storm event. Any facility that constitutes a dam as defined in PADEP Chapter 105 regulations may require a permit under dam safety regulations. Any facility located within a PennDOT right-of-way must meet PennDOT minimum design standards and permit submission requirements. If the primary drainage facilities do not have capacity for future flows, then a safe drainage path must be provided to convey up to the one-hundred-year design storm (without impacting structures).

(12) 

Storm sewers must be able to convey postdevelopment runoff from a minimum twenty-five-year design storm without surcharging inlets.

(13) 

Adequate erosion protection shall be provided along all open channels and at all points of discharge.

(14) 

The design of all stormwater management facilities shall incorporate sound engineering principles and practices. The Borough shall reserve the right to disapprove any design that would result in the occurrence or continuation of an adverse hydrologic or hydraulic condition within the watershed.

(15) 

Stormwater drainage systems shall be provided in order to permit unimpeded flow along natural watercourses except as modified by stormwater management facilities or open channels consistent with this chapter.

(16) 

Areas of existing diffused drainage discharge shall be subject to any applicable discharge criteria in the general direction of existing discharge, whether proposed to be concentrated or maintained as diffused drainage areas, except as otherwise provided by this chapter. If diffused flow is proposed to be concentrated and discharged onto adjacent property, the applicant must document to the Borough in accordance with Subsection E(17) of this section that adequate downstream conveyance exists to safely transport the concentrated discharge, or the applicant must obtain drainage easements from affected downstream property owners and provide the facilities to safely convey the flow.

(17) 

Downstream hydraulic capacity analysis. Any downstream capacity hydraulic analysis conducted in accordance with this chapter shall use the following criteria for determining adequacy for accepting increased peak flow rates:

(a) 

Natural or man-made channels or swales must be able to convey the increased runoff associated with a two-year return period event within their banks at velocities consistent with protection of the channels from erosion. Acceptable velocities shall be based upon criteria included in the PADEP Erosion and Sediment Pollution Control Program Manual.

(b) 

Natural or man-made channels or swales must be able to convey the increased twenty-five-year return period runoff without creating any hazard or adverse effects to adjacent or downstream persons or property.

(c) 

Culverts, bridges, storm sewers, or any other facilities which must pass or convey flows from the tributary area must be designed in accordance with PADEP, Chapter 105 regulations (if applicable) and, at a minimum, pass the increased twenty-five-year return period runoff.

(18) 

Where a development site is traversed by watercourses, riparian buffers shall be provided conforming to the line of such watercourses. The width of the buffers shall be determined as set forth in Subsection E(4) of this section. Excavating, placing of fill, building structures, or making any alterations that may adversely affect the flow of stormwater within any portion of the riparian buffer shall be prohibited unless the proposed work is associated with a regulated wetlands mitigation program. The buffer must be defined and restricted by a restrictive covenant.

(19) 

When it can be shown that, due to topographic conditions, natural drainageways on the site cannot adequately provide for drainage, open channels may be constructed conforming substantially to the line and grade of such natural drainageways. Work within natural drainageways shall be subject to approval by PADEP through the joint permit application process, or, where deemed appropriate by PADEP, through the general permit process.

(20) 

Any stormwater management facilities regulated by this chapter that would be located in or adjacent to waters of the commonwealth or wetlands shall be subject to approval by the PADEP through the joint permit application process, or, where deemed appropriate by PADEP, the general permit process. When there is a question as to whether wetlands may be involved, it is the responsibility of the applicant or his agent to show that the land in question cannot be classified as wetlands; otherwise, approval to work in the area must be obtained from PADEP.

(21) 

Any stormwater management facilities regulated by this chapter that would be located on or flow into state highway rights-of-way or stormwater systems shall be subject to approval by PennDOT.

(22) 

Minimization of impervious surfaces and infiltration of runoff through seepage beds, infiltration trenches, etc. are required, where soil conditions permit, to reduce the size or eliminate the need for detention facilities.

(23) 

In order to promote overland flow and infiltration/percolation of stormwater, roof drains must discharge into an accepted BMP providing infiltration and filtering of the stormwater.