For any of the regulated activities of this Part 1, prior to the final approval of subdivision and/or land development plans or the issuance of any permit or the commencement of any land disturbance activity, the owner, subdivider, developer or his agent shall submit a drainage plan for approval.
The following items shall be included in the drainage plan:
A. 
General requirements.
(1) 
A general description of the project.
(2) 
A general description of the proposed stormwater controls.
B. 
Map(s). Map(s) of the project area shall show the following:
(1) 
The location of the project relative to highways, municipalities or other identifiable landmarks.
(2) 
Existing contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
(3) 
Streams, lakes, ponds or other bodies of water within the project area.
(4) 
Other physical features, including existing drainage swales and areas of natural vegetation to be preserved.
(5) 
Locations of proposed underground utilities, sewers and water lines.
(6) 
An overlay showing soil types and boundaries.
(7) 
Proposed changes to land surface and vegetative cover.
(8) 
Proposed structures, roads, paved areas and buildings.
(9) 
Final contours at intervals of two feet. In areas of steep slopes (greater than 15%), five-foot contour intervals may be used.
(10) 
Stormwater management district boundaries applicable to the site.
C. 
Stormwater management controls.
(1) 
All stormwater management controls must be shown on a map and described, including:
(a) 
Groundwater recharge methods such as seepage pits, beds or trenches. When these structures are used, the locations of septic tank infiltration areas and wells must be shown.
(b) 
Other control devices or methods such as rooftop storage, semipervious paving materials, grass swales, parking lot ponding, vegetated strips, detention or retention ponds, storm sewers, etc.
(c) 
Water quality controls if necessary.
(2) 
All calculations, assumptions and criteria used in the design of the control device or method must be shown.
D. 
Maintenance program. A maintenance program for all stormwater management control facilities must be included. This program must include the proposed ownership of the control facilities and the maintenance requirements for the facilities and detail the financial responsibility for the required maintenance.
[Amended 1-4-2016 by Ord. No. 345; 6-17-2025 by Ord. No. 426]
The municipality requires submission of a complete SWM site plan, as specified in this Part 1.
A. 
Proof of application or documentation of required permit(s) or approvals for the programs listed below shall be part of the plan:
(1) 
National Pollutant Discharge Elimination System (NPDES) permit for stormwater discharges from construction activities, when required.
(2) 
Any other permit under applicable state or federal regulations.
B. 
Five copies of the SWM site plan shall be submitted and distributed as follows:
(1) 
Three copies to the municipality accompanied by the requisite fees, as specified in this Part.
(2) 
Two copies to the County Conservation District when required.
C. 
If any submissions to the agencies listed above are found to be incomplete, the municipalities have the option of notifying the applicant and requesting specific information missing from the submission. The time period within which the municipality must review the application shall not start until the municipality has determined that the submission is complete.
D. 
Additional copies shall be submitted as requested by the municipality, County Conservation District, or DEP.
A. 
The Township Engineer shall review the drainage plan for consistency with the general requirements or the specific requirements adopted for the Stony Creek/Saw Mill Run Stormwater Management Plan as embodied by this Part 1 and against any additional storm drainage provisions contained in Chapter 129, Subdivision and Land Development, or Chapter 160, Zoning, of the Code of the Township of Whitpain, as applicable.
B. 
The County Planning Commission shall provide an advisory review of the drainage plan for consistency with general requirements or the specific requirements adopted for the Stony Creek/Saw Mill Run Stormwater Management Plan.
C. 
For regulated activities specified in § 125-5H(1) the Township Planning Commission shall provide written comments to the Township, within a time frame consistent with established procedures under the Pennsylvania Municipalities Planning Code, as to whether the drainage plan is consistent with the stormwater management plan.[1]
[Amended 1-4-2016 by Ord. No. 345]
[1]
Editor's Note: Former Subsection D, regarding regulated activities as specified in § 125-5H(4) and (5), was repealed 1-4-2016 by Ord. No. 345. This ordinance also provided for the redesignation of former Subsection E as Subsection D.
D. 
The Township shall not approve any subdivision or land development or building permit application (regulated activities in § 125-5H if the drainage plan has been found to be inconsistent with the stormwater management plan as determined by the Township Engineer.
Modification to a submitted drainage plan for a proposed development site which involves a change in control methods or techniques or which involves the relocation or redesign of control measures or which is necessary because soil or other conditions are not as stated on the drainage plan (as determined by the Municipal Engineer) shall require a resubmission of the modified drainage plan consistent with § 125-27 subject to review per § 125-28 of this Part 1.
[Added 7-18-2006 by Ord. No. 295;[1] amended 1-4-2016 by Ord. No. 345; 6-17-2025 by Ord. No. 426]
A. 
Applicability of stormwater detention/storage requirements. Stormwater detention/storage facilities or a fee in lieu of such facilities shall be provided in accordance with the following provisions:
(1) 
Stormwater from any new impervious surfaces constructed on an improved residential lot shall be controlled in accordance with the following requirements:
(a) 
Stormwater from new impervious surfaces that meets the exemption criteria set forth in § 125-7 of the Code of Whitpain Township, measured cumulatively from the date of adoption of this Part 1, shall be exempted from these requirements and does not need to be detained.
(b) 
Stormwater from new impervious surfaces not exempted shall be detained/stored through one of the following mechanisms:
[1] 
Designed in accordance with underground infiltration facilities for a small construction project.
[2] 
Designed in accordance with all other provisions of Chapter 125 of the Code of the Township of Whitpain.
[3] 
Payment of a fee in lieu of stormwater detention/storage facilities.
B. 
Simplified stormwater control facilities. A detention basin or underground infiltration basin that meets the following requirements shall be provided for simplified stormwater management control:
(1) 
The detention basin shall provide 0.28 cubic feet of storage capacity for each one square foot of new impervious surface, or the underground stone infiltration basin shall provide 0.7 cubic feet of storage capacity for each one square foot of new impervious surface in accordance with § 125-7.
(2) 
The maximum depth of the detention basin shall be four feet.
(3) 
The maximum side slopes of the detention basin shall be three to one.
(4) 
An infiltration test shall be performed, such as a double ring infiltrometer test, to determine the appropriate hydraulic conductivity rate. The test shall be in compliance with the soil infiltration testing requirements included in Appendix C.[2]
[2]
Editor's Note: Said appendix is included as an attachment to this chapter.
C. 
Fee-in-lieu alternative for detention/storage facilities.
(1) 
In order to address flooding and erosion problems found in all watersheds in Whitpain Township except the Wissahickon Creek Watershed, applicants may pay a fee in lieu of stormwater detention/storage facilities as an alternative to the construction of stormwater detention/storage facilities. When fees are offered by an applicant, the Township may, but shall not be required to, accept the fees, provided that the proposed stormwater solution meets the requirements in § 125-30.
(2) 
These fees shall be used to construct Township funded or sponsored stormwater management facilities in all watersheds in Whitpain Township, except the Wissahickon Creek Watershed. Additionally, such fees may be used for the acquisition of land and rights-of-way, engineering, legal and planning costs and all other costs, including debt service, related to the construction of necessary stormwater control facilities.
(3) 
Applicants shall pay the following fees in lieu of stormwater facilities:
(a) 
Fees in lieu of stormwater detention/storage facilities on an improved residential lot shall be based on the square feet of new impervious surface area that will not be controlled. Such fee shall be established at $7.50 per square foot as of the date of the ordinance and updated annually based on the Consumer Price Index (CPI-U published for the Greater Philadelphia area by the U.S. Department of Labor).
(4) 
Fees collected by the Township shall be deposited in an interest-bearing account in a bank authorized to receive deposits of Township funds. Interest earned by the account shall be credited to that account and shall be used for the same purposes as money deposited in the account.
[1]
Editor's Note: This ordinance also repealed former § 125-30, Hardship waivers, as amended 9-21-2004 by Ord. No. 280-1.